Name: B4 Homeostasis and...

B4 Homeostasis and Response35 Questions

Name: ________________________

Class: ________________________

Date: ________________________

Time:

Marks:

Comments:

of 120Brookvale Groby Learning Trust

Amylase is an enzyme that digests starch.

A student investigated the effect of pH on the activity of amylase.

This is the method used.

1. Mix amylase solution and starch suspension in a boiling tube.

2. Put the boiling tube into a water bath at 25 °C.

3. Remove a drop of the mixture every 30 seconds and test it for the presence of starch.

4. Repeat the investigation at different pH values.

The table below shows the students’ results.

pHTime when no starch was

detected in minutes

5.0 7.0

5.5 4.5

6.0 3.0

6.5 2.0

7.0 1.5

7.5 1.5

8.0 2.0

(a) The student concluded pH 7.25 was the optimum pH for the amylase enzyme.

This is not a valid conclusion.

Suggest two reasons why.

1. _________________________________________________________________

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2. _________________________________________________________________

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(2)

1


(b) The student did another investigation.


1. Put amylase solution and starch suspension into a boiling tube.

2. Make the pH 7.25.

3. Put the boiling tube into a water bath at 25 °C.

4. Measure the amount of sugar produced every 30 seconds.

The results are shown in the figure below.

Calculate the mean rate of sugar produced per minute during the first 5 minutes.

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Mean rate = ________________ units per minute

(2)


(c) Iodine solution is added to a sample taken from the boiling tube after 10 minutes and 60minutes.

Suggest what you would see in these samples.

After 10 minutes _____________________________________________________

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After 60 minutes _____________________________________________________

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(2)

(d) The scientist repeated the investigation at 37 °C.

Draw a line on the figure above to show the results the scientist would get.

(2)

(e) The same investigation was done at 65 °C.

How would this affect the results?

Explain why.

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(3)

(Total 11 marks)


A person with Type 1 diabetes does not produce enough of the hormone insulin.

(a) Where is the hormone insulin produced?

Tick one box.

Brain

Pancreas

Pituitary

Thyroid

(1)

2

(b) How does insulin travel around the body?

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(1)


(c) The same concentration and volume of glucose solution was given to two people.

• Person with Type 1 diabetes.

• Person without Type 1 diabetes.

The figure below shows how the blood glucose concentration of these two people changedafter they each drank a glucose solution.

Look at the figure above.

Compare the blood glucose concentrations of the two people.

Include similarities and differences in your answer.

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(4)

(d) People with diabetes may be asked to control their diet.

Explain how this can help to reduce the risk of developing health problems.

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(3)

(Total 9 marks)

Neurones pass information around the body.

(a) Why are reflex reactions important?

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(1)

3

(b) Caffeine is a drug found in coffee.

After a person drinks coffee information passes through neurones in the nervous systemmore quickly.

Suggest a hypothesis for the effect of caffeine concentration on reaction time.

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(1)


(c) Two students investigated the effect of caffeine concentration on reaction time.


1. Student A drinks a cup of coffee.

2. Student B holds a ruler above Student A’s hand.

3. Student B drops the ruler.

4. Student A catches the ruler as quickly as she can.

5. The distance the ruler falls is recorded.

Suggest how this method could be improved to produce valid results.

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(6)

(Total 8 marks)


People with Type 1 diabetes cannot control the concentration of glucose in their blood.

This is because they do not produce the hormone insulin.

The same concentration and volume of glucose solution is given to two people.

• Person with Type 1 diabetes.

• Person without Type 1 diabetes.

Figure 1 shows how the blood glucose concentration of these people changes after they eachdrink a glucose solution.

Figure 1

4


(a) The blood glucose concentration increases at a faster rate in the person with diabetescompared to the person without diabetes.

Calculate how much faster the rate of increase in blood glucose concentration is in theperson with diabetes.

Give the rate of increase for the first 30 minutes after drinking the glucose solution.

Give your answer in units / h.

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___________________ Units / h

(2)

(b) The blood glucose concentration of the person without diabetes starts to change 30minutes after drinking the glucose solution.

Explain why the blood glucose concentration changes.

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(2)


(c) People with diabetes should try to keep their blood glucose concentration within the samerange as a person without diabetes.

Most people with Type 1 diabetes regularly check their blood glucose concentration using ameter, as shown in Figure 2.

The meter reading is used to estimate how much insulin they need to inject.

Figure 2

© Vincente Barcel/Hemera/Thinkstock

Figure 3 shows a new system.

It is connected to the person all the time.

Figure 3

The new system:

• gives better control of blood glucose concentration

• reduces the number of times the glucose concentration falls too low.


Evaluate the two systems as methods for controlling blood glucose concentrations forpeople with Type 1 diabetes.

Give a justified conclusion to your evaluation.

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(4)

(d) How does the body respond if slightly too much insulin is injected into the body.

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(5)

(Total 13 marks)


Hormones are released from glands.

(a) Which gland produces hormones to control other glands in the endocrine system?

Tick one box.

Adrenal

Ovary

Pituitary

Thyroid

(1)

5


(b) The figure below shows the level of adrenaline in a man’s bloodstream while he waswatching a 12-minute film.

Calculate the percentage increase in adrenaline after point B.

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Percentage increase in adrenaline = _________________

(2)

(c) Suggest why the percentage increase in adrenaline after point B is different from thepercentage increase after point A.

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(2)


(d) Adrenaline causes changes in the body to prepare for a ‘fight or flight’ response.

What changes in the man’s body are caused by adrenaline?

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(2)

(Total 7 marks)

The figure below shows how the concentrations of the reproductive hormones in the blood of awoman change over 28 days.

(a) Name hormones A and B.

A _________________________________________________________________

B _________________________________________________________________

(2)

6

(b) Use information from the figure above to explain what happens on Day 14.

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(2)


(c) In Vitro Fertilisation (IVF) treatment can be used to help women become pregnant.

IVF uses some of the hormones shown in the figure above.

Explain why IVF increases the chance of some women becoming pregnant.

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(6)

(Total 10 marks)


Our nervous system controls our reactions.

Figure 1 shows the part of the nervous system involved in the rapid response to a stimulus.

Figure 1

(a) What is this type of rapid response called?

Tick one box.

Circular action

Fast action

Forced action

Reflex action

(1)

7


(b) Features of the nervous system are labelled A, B, C, D and E on Figure 1.

Draw one line from each feature to the correct label from Figure 1.

Feature Label

A

Effector B

Relay neurone C

Sensory neurone D

E

(3)

(c) Two students compare their reactions using a ruler.


1. Student A sits with his elbow on a table top.

2. Student B holds the ruler so the bottom of the ruler is level with the top of student A’sthumb.


4. Student A catches the ruler.

5. Record the drop distance.

6. Repeat steps 1 to 5 four more times.

7. Repeat the whole experiment with student A dropping the ruler and student Bcatching it.


Both students are right-handed.

The students are testing the hypothesis:

the drop distance of the ruler is smaller when a right-handed person uses their righthand to catch the ruler.

Student A uses his right hand to catch the ruler.

Student B uses her left hand to catch the ruler.

Complete the sentence.

Use an answer from the box.

control dependent independent

The drop distance was the ________________________________ variable.

(1)


(d) The table below shows the students’ results.

StudentDrop distance in cm

Test 1 Test 2 Test 3 Test 4 Test 5

Student A 17.5 15.5 15.0 23.5 17.0

Student B 20.5 19.5 21.0 19.0

Figure 2 shows student B’s Test 2 result.

Figure 2

Use Figure 2 to complete the missing result for Test 2.

Write the answer in the table above.

(1)


(e) What was the resolution of the ruler the students used?

Tick one box.

0.1 cm

0.5 cm

1 cm

10 cm

(1)

(f) One of the results in the table above is anomalous.

Identify the anomalous result.

Give the reason why you chose your answer.

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(2)


(g) The students are testing the hypothesis:

the drop distance of the ruler is smaller when a right-handed person uses their righthand to catch the ruler.

The results in the table above are not a good test of the hypothesis.

What is one reason why?

Tick one box.

The drop distances are very variable

The drop distance for Student A is sometimes biggerthan the drop distance for Student B

The results are for the left and right hands of differentpeople

The drop distances are not measured accuratelyenough

(1)

(Total 10 marks)

Blood sugar levels in the body are controlled by insulin.

(a) How does insulin travel around the body?

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(1)

8


(b) The table below shows the blood sugar levels for two people after eating a meal.

Time after eatingin hours

Blood sugar levels in mg per 100 cm3 of blood

Person A Person B

0 70 130

1 150 230

2 90 185

3 80 165

4 75 140

Use data from the table above to complete the graph in the figure below.

Plot the points for person A.

The first two points have been plotted for you.

Draw a line through all the points.

(3)

(c) How long after the meal is person B’s insulin production at its peak?

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(1)


(d) What is the greatest decrease in the blood sugar level of person B in an hour?

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Decrease = ___________________ mg per 100 cm3

(2)

(e) Estimate how long after eating the meal it will take for person B’s blood sugar level toreturn to the level before the meal.

Show your working on the figure above.

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(2)

(Total 9 marks)


The nervous system allows humans to respond to their surroundings.

The figure below shows two nerve pathways.

Nerve pathway A Nerve pathway B

(a) Nerve pathway A is 92 cm long.

A nerve impulse travels along pathway A at 76.2 m / s.

Calculate how long it takes for the nerve impulse to travel the length of the pathway.

Use the equation:

distance = speed × time

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Time = _________________ s

(3)

9

(b) Nerve pathways A and B are the same length.

The nerve impulse takes longer to travel along pathway A than along pathway B.

Use the figure above to explain why.

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(3)


(c) Two students compare their reactions using a ruler.


1. Student A sits with his elbow on a table top.

2. Student B holds the ruler so the bottom of the ruler is level with the top of student A’sthumb.


4. Student A catches the ruler.

5. Record the drop distance.

6. Repeat steps 1 to 5 four more times.

7. Repeat the whole experiment with student A dropping the ruler and student Bcatching it.

Both students are right-handed.

Student A uses his right hand to catch the ruler.

Student B uses her left hand to catch the ruler.

The table below shows the students’ results.

StudentDrop distance in mm


Student A – right hand 203 167 140 156 163

Student B – left hand 230 211 279 215 264

What is the range of student A’s results?

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(1)


(d) The students are testing the hypothesis:

The drop distance of the ruler is smaller when a right-handed person uses their righthand to catch the ruler.

The students’ results in the table above are not a good test of the hypothesis.

Suggest what the students should have done to test the hypothesis.

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(3)


(e) Student A’s mean reaction time was 0.19 s.

Mean reaction time can be calculated using the equation:

Calculate the mean reaction time for Student B.

Give your answer to two significant figures.

Student B’s results are repeated here to help you answer the question.

Drop distance in mm


Student B – left hand 230 211 279 215 264

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Mean reaction time = ____________ s

(4)

(Total 14 marks)


The rate of chemical reactions can be changed by changing the conditions.

(a) Methane burns in oxygen to produce carbon dioxide and water.

The activation energy for the reaction is 2648 kJ / mol.

The reaction gives out 818 kJ / mol of energy.

The figure below shows the reaction profile for this reaction.

Complete the reaction profile.

Draw arrows to represent:

• the activation energy

• the energy given out.

(4)

10

(b) What percentage of the activation energy is the energy given out?

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(1)

(c) Calcium carbonate decomposes when it is heated:

The decomposition of calcium carbonate is an endothermic reaction.

How would the reaction profile for decomposition of calcium carbonate be different from thereaction profile of methane burning in oxygen?

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(1)


(d) Catalysts are used in chemical reactions in industry.

Give two properties of catalysts.

For each property, explain why it makes the catalyst useful in industry.

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(4)

(e) Enzymes are biological catalysts.

What type of molecule is an enzyme?

Tick one box.

Carbohydrate

Hydrocarbon

Lipid

Protein

(1)

(f) If enzymes are denatured they stop working.

Give two ways an enzyme can be denatured.

1. _________________________________________________________________

2. _________________________________________________________________

(2)


(g) An enzyme called lactase catalyses the reaction that breaks down lactose to smallermolecules.

One model used to explain how enzymes affect reactions is called the lock and key model.

Use the lock and key model to explain why lactase cannot be used to speed up allchemical reactions.

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(3)

(Total 16 marks)

Amylase catalyses the breakdown of starch into sugars.

A student investigated the effect of amylase on the reaction at different temperatures.

Figure 1 shows the apparatus the student used.

Figure 1

11



1. Put starch suspension into a test tube.

2. Add amylase solution.

3. Put the test tube in a beaker of water at 15 °C.

4. Remove a small sample of the mixture every 30 seconds and put in a spotting tile.

5. Test the sample for starch.

6. Time how long it takes to break down all of the starch in the mixture.

7. Repeat steps 1–5 at 20 °C, 25 °C and 30 °C.

8. Repeat for each temperature twice more.

The table below shows the student’s results.

Time taken until there was no starch in the sample in

minutes

Temperature in°C

Test 1 Test 2 Test 3 Mean

15 6.1 9.4 10.0 8.5

20 4.8 5.0 4.6 4.8

25 3.0 2.5 3.0 3.2

30 1.5 2.0 2.0

(a) One of the results in the table above is anomalous.

Draw a ring around the anomalous result.

(1)

(b) Calculate the mean for 30 °C.

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(1)


(c) Figure 2 shows a graph of the student’s results.

Figure 2

Use the graph to predict how long it would take to break down all of the starch at 10 °C.

Time = _________________ minutes

(1)

(d) The student tested samples of the mixture for starch every 30 seconds.

In each test she added one drop of iodine to the sample in the spotting tile.

Predict the colour of the samples from the 20 °C test at 4.0 minutes and 7.0 minutes.

Colour at 4.0 minutes __________________________________________

Colour at 7.0 minutes __________________________________________

(2)


(e) The student did a fourth test at 30 °C.

In this test the starch did not break down, even after 45 minutes.

Why did the amylase not break down the starch in this test?

Tick one box.

The amylase solution and the starch suspension were mixed before thestart of the experiment.

The amylase solution had been prepared with water at 95 °C.

The amylase solution had been prepared with water at 20 °C.

The amylase solution had been stored in the fridge.

(1)

(f) The student made the following conclusion about the optimum temperature for amylase towork at.

‘Amylase works fastest at 40 °C’

Her teacher said that this is not a valid conclusion from her results.

Describe how the student could change her method to give results that would improve thevalidity of her conclusion.

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(6)

(Total 12 marks)


The human body is organised to carry out many different functions.

(a) Use words from the box to complete Figure 1 by putting the parts of the body in order ofsize from smallest to largest.

The smallest one has been done for you.

(2)

12

(b) The stomach is made of different types of tissue.

Draw one line from each type of stomach tissue to the correct description.

(3)


(c) Animals can react to their surroundings because they have nervous systems.

A student investigated the behaviour of small animals called woodlice.

The student set up the investigation as shown in Figure 2.

• The student covered one half of a Petri dish with black paper to make that side of thePetri dish dark.

• The other side had no cover.

• The student put five woodlice into each side of the dish and then put the clear Petridish lid back on the dish.

Figure 2

After 30 minutes, all the woodlice had moved to the dark side of the Petri dish.


(i) In this investigation, what is the stimulus that the woodlice responded to?

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(1)

(ii) In this investigation, what is the response that the woodlice made?

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(1)

(iii) The student concluded that woodlice prefer dark conditions.

Give two ways in which the student could improve the investigation to be sure thathis conclusion was correct.

1. ____________________________________________________________

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2. ____________________________________________________________

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(2)

(Total 9 marks)

This question is about hormones.

(a) (i) Hormones carry messages.

What type of messenger is a hormone?

Draw a ring around the correct answer.

chemical electrical environmental

(1)

13

(ii) Which part of the brain secretes hormones?


cerebellum medulla pituitary gland

(1)


(b) Figure 1 shows the level of a pregnancy hormone over a 40-week pregnancy.

This hormone can be detected in a pregnancy test.

Figure 1

A woman takes a pregnancy test.

In which week of pregnancy is the test most likely to give a positive result?

Use information from Figure 1.

Write the correct answer in the box.

(1)


(c) Figure 2 shows the levels of three other hormones during pregnancy.

The baby is usually born at about 40 weeks.

Figure 2

Adaptation by kind permission of Biozone International

(i) Describe the patterns in the levels of oestrogen and progesterone from 0 to 36weeks.

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(4)

(ii) Which hormone is likely to stimulate contractions of the uterus (womb) when thebaby is born?

Use information from Figure 2 to give a reason for your answer.

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(2)

(Total 9 marks)


(a) Control systems help to keep conditions in the human body relatively constant.

What is the general name for the processes that keep body conditions relatively constant?


eutrophication homeostasis hydrotropism

(1)

14

(b) The concentration of glucose in the blood is controlled by hormones.

Use the correct answer from the box to complete each sentence.

glucagon glycerol glycogen

kidney liver pancreas

When the blood glucose concentration increases, an organ called

the ______________________ releases the hormone insulin.

Insulin causes glucose to move from the blood into the cells of the muscles

and the ______________________ .

Inside these organs, the glucose is changed into a carbohydrate called

______________________ , which can be stored.

When the blood glucose concentration falls, another hormone is released,

which causes the storage carbohydrate to break down into glucose again.

This hormone is called ______________________ .

(4)


(c) A person with Type 1 diabetes does not make enough insulin.

The person needs to test their blood at intervals throughout the day.

If the concentration of glucose in their blood is too high, the diabetic person needs to injectinsulin.

(i) Insulin is a protein.

It must be injected and cannot be taken by mouth.

Explain why.

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(2)

(ii) Apart from injecting insulin, give one other way that a diabetic person couldhelp to control the concentration of glucose in their blood.

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(1)


(d) Pet dogs have been trained to detect if the concentration of glucose in the blood of theirdiabetic owners is outside the normal healthy range. These dogs are called ‘medicalresponse dogs’.The dogs respond in different ways. They may bark, jump up, or stare at their owners.Theymay even fetch a blood-testing kit.

(i) Suggest what stimulus the dogs might be responding to when they behave likethis.

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(1)

(ii) Table 1 shows how the concentration of glucose varied in blood samples fromfive diabetic people. Measurements were made both before and after getting amedical response dog.

Table 1

Mean percentage of blood samples withdifferent concentrations of glucose from the

five diabetic people

Number ofblood

samplesmeasured

Low glucoseWithin normal

range ofglucose

High glucose

Before getting a dog 1704 32.6 54.8 12.6

After getting a dog 1724 18.6 61.6 19.8

A survey was made of the effect of a medical response dog on the lives of 16 diabeticpeople.

Table 2 shows how well these diabetic people agreed with each statement in thesurvey.

Table 2

Statement in surveyTotallyagree

Somewhatagree

Neitheragreenor

disagree

Somewhatdisagree

Totallydisagree

I am more independentsince getting my dog.

12 2 2 0 0

There are disadvantagesto having a medical

0 0 4 4 8


response dog.

I trust my dog to alert mewhen my sugar levels arelow.

11 3 1 0 1

I trust my dog to alert mewhen my sugar levels arehigh.

6 7 0 1 2

Evaluate how useful medical response dogs are for warning diabetic people that theconcentration of glucose in their blood is outside the normal range.

Use information from Tables 1 and 2.

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(5)


(e) Table 3 shows the concentrations of some substances in the urine of a non-diabetic personand in the urine of a diabetic person.

Table 3

Concentration of substance in urine in g per dm3

Substance Non-diabetic person Diabetic person

Protein 0 0

Glucose 0 2.0

Urea 20.0 19.5

Sodium ions 6.0 5.8

Compare the results for the non-diabetic person and the diabetic person.Give reasons for any differences.

Use your knowledge of how the kidney works.

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(5)

(Total 19 marks)

Humans use the nervous system to react to changes in the environment.

(a) (i) Which word means a change in the environment?


neurone reflex stimulus

(1)

15


(ii) Figure 1 shows a light receptor cell.

Use the correct answer from the box to label part A on Figure 1.

chloroplast cytoplasm vacuole

(1)


(b) Figure 2 shows a boy riding a bicycle on a sunny day.

© Stockbyte/Thinkstock

(i) Receptors in the boy’s body detect changes in the environment.

Complete the table to show which organ of the body contains the receptors for eachchange in the environment.

Change in the environmentOrgan that contains the

receptors

Sound of traffic from behind him

Flashing blue lights of a police car

Cooler air temperature in the shadows

(3)


(ii) The boy’s response to danger is to pull on the bicycle brakes.

Which type of effector causes this response?

Tick ( ) one box.

A gland

A muscle

A synapse

(1)

(Total 6 marks)

This question is about the nervous system.

(a) Describe the function of receptors in the skin.

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(2)

16


(b) A response is caused when information in the nervous system reaches an effector.

(i) There are two different types of effector.

Complete the table to show:

• the two different types of effector

• the response each type of effector makes.

(4)

(ii) Some effectors help to control body temperature.

Give one reason why it is important to control body temperature.

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(1)

(Total 7 marks)


Blood glucose concentration in humans must be kept between 4.4 and 6.1 mmol per dm3.

Four students, A, B, C and D, tested their blood glucose concentration with glucose testingstrips.

The diagram shows the results of their tests and the key from the test strip bottle.

(a) (i) Which student, A, B, C or D, has diabetes and has eaten a large piece of cake?

(1)

(ii) Which student, A, B, C or D, is in most need of eating carbohydrates?

(1)

(iii) Which student, A, B, C or D, has a healthy blood glucose concentration?

(1)

17


(b) (i) Name the hormone that people with diabetes inject to prevent their blood glucoseconcentration from becoming too high.

______________________________________________________________

(1)

(ii) Blood glucose concentration is monitored in the body.

Which organ monitors blood glucose concentration?


brain liver pancreas

(1)

(Total 5 marks)

In this question you will be assessed on using good English, organising information clearly andusing specialist terms where appropriate.

Homeostasis keeps conditions in the body relatively constant.

The amount of water in the body is controlled by homeostasis.

Kidney function is controlled by a gland in the brain.

18


Describe how the water content of the blood is controlled.

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(Total 6 marks)

(a) Diagram 1 shows the neurones and parts of the body involved in a response to touching ahot object.19


Diagram 1

A neurone is a nerve cell. Neurones carry impulses around the body.

(i) Draw a ring around the correct answer to complete each sentence.

Neurone A is a

motor neurone.

relay neurone.

sensory neurone.

At point Y there is a tiny gap between two neurones called

an effector.

a receptor.

a synapse.

(2)


(ii) The hand touches a hot object. An impulse travels through the nervous system to themuscle (point X). The muscle moves the hand away from the hot object.

What does the muscle do to move the hand away from the hot object?

Tick ( ) one box.

contract

relax

stretch

(1)

(iii) The action described in part (a) (ii) is a reflex action.

How can you tell that this action is not a conscious action?

Use information from the diagram.

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(1)

(iv) Reflex actions like this are useful.

Explain why.

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(2)

(b) Some students investigated the effect of caffeine on a person’s reaction time.

The students used the following steps.

1. One student held a ruler just above a second student’s hand, as shown in Diagram 2.


Diagram 2

2. The student let go of the ruler. The second student caught it as soon as possible, asshown in Diagram 3.

Diagram 3

3. The students repeated this experiment seven more times.

4. The student catching the ruler then drank a cup of strong coffee.

Coffee contains caffeine.

5. Fifteen minutes after drinking the coffee the students repeated steps 1 to 3.

Table 1 and Table 2 show the students’ results.


Table 1 Table 2

Distance ruler fellbefore it was caught

in cm

Distance ruler fellbefore it was caught

in cm

Before drinking coffee After drinking coffee

18 8

21 13

25 11

15 17

19 10

16 14

12 13

21 13

Mean = 18.4 Mean = 12.4

(i) The students used the reading on the ruler as a measure of the reaction time.

What do the results show about the effect of caffeine on reaction time?

______________________________________________________________

______________________________________________________________

(1)

(ii) Look carefully at all the data in Table 1 and Table 2.

Using the data in Table 1 and Table 2, give one reason why a scientist may notaccept your conclusion in part (b) (i).

______________________________________________________________

______________________________________________________________

(1)


(iii) How could the students improve their investigation?

Suggest two ways.

1. ____________________________________________________________

______________________________________________________________

2. ____________________________________________________________

______________________________________________________________

(2)

(Total 10 marks)

The diagram below shows the pathway for a simple reflex action.

20

(a) What type of neurone is neurone X?


motor neurone relay neurone sensory neurone

(1)

(b) There is a gap between neurone X and neurone Y.

(i) What word is used to describe a gap between two neurones?


effector receptor synapse

(1)

(ii) Draw a ring around the correct answer to complete the sentence.

Information passes across the gap as

a chemical.

an electrical impulse.

pressure.

(1)


(c) Describe what happens to the muscle when it receives an impulse from neurone Z. Howdoes this reflex action help the body?

What happens to the muscle ___________________________________________

___________________________________________________________________

How this helps the body _______________________________________________

___________________________________________________________________

(2)

(Total 5 marks)

The diagram below shows how a nerve impulse passing along a relay neurone causes animpulse to be sent along another type of neurone, neurone X.

21

(a) What type of neurone is neurone X?

___________________________________________________________________

(1)

(b) Describe how information passes from the relay neurone to neurone X.Use the diagram to help you.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)


(c) Scientists investigated the effect of two toxins on the way in which information passesacross synapses. The table below shows the results.

Toxin Effect at the synapse

CurareDecreases the effect of the chemicalon neurone X

StrychnineIncreases the amount of the chemicalmade in the relay neurone

Describe the effect of each of the toxins on the response by muscles.

Curare _____________________________________________________________

___________________________________________________________________

___________________________________________________________________

Strychnine __________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(Total 6 marks)

Phenylketonuria (PKU) is an inherited condition. PKU makes people ill.

(a) PKU is caused by a recessive allele.

(i) What is an allele?

______________________________________________________________

______________________________________________________________

(1)

22

(ii) What is meant by recessive?

______________________________________________________________

______________________________________________________________

(1)


(b) The diagram below shows the inheritance of PKU in one family.

(i) Give one piece of evidence from the diagram that PKU is caused by a recessiveallele.

______________________________________________________________

______________________________________________________________

(1)

(ii) Persons 6 and 7 are planning to have another child.Use a genetic diagram to find the probability that the new child will have PKU.

Use the following symbols in your answer:

N = the dominant allele for not having PKU

n = the recessive allele for PKU.

Probability = _________________________

(4)

(c) Persons 6 and 7 wish to avoid having another child with PKU.

A genetic counsellor advises that they could produce several embryos by IVF treatment.

(i) During IVF treatment, each fertilised egg cell forms an embryo by cell division.

Name this type of cell division.

______________________________________________________________

(1)


(ii) An embryo screening technique could be used to find the genotype of each embryo.

An unaffected embryo could then be placed in person 7’s uterus.

The screening technique is carried out on a cell from an embryo after just three celldivisions of the fertilised egg.

How many cells will there be in an embryo after the fertilised egg has

divided three times?

(1)

(iii) During embryo screening, a technician tests the genetic material of the embryo tofind out which alleles are present.

The genetic material is made up of large molecules of a chemical substance.

Name this chemical substance.

______________________________________________________________

(1)

(d) Some people have ethical objections to embryo screening.

(i) Give one ethical objection to embryo screening.

______________________________________________________________

(1)

(ii) Give one reason in favour of embryo screening.

______________________________________________________________

(1)

(Total 12 marks)


The diagram shows the position of two glands, A and B, in a woman.

(a) (i) Name glands A and B.

A ___________________________________

B ___________________________________

(2)

23

(ii) Gland A produces the hormone Follicle Stimulating Hormone (FSH).

FSH controls changes in gland B.

How does FSH move from gland A to gland B?

______________________________________________________________

(1)


(b) (i) A woman is not able to become pregnant. The woman does not produce matureeggs. The woman decides to have In Vitro Fertilisation (IVF) treatment.

Which two hormones will help the woman produce and release mature eggs?

Tick ( ) one box.

FSH and Luteinising Hormone (LH)

FSH and oestrogen

Luteinising Hormone (LH) and oestrogen

(1)

(ii) Giving these hormones to the woman helps her to produce several mature eggs.Doctors collect the mature eggs from the woman in an operation.

Describe how the mature eggs are used in IVF treatment so that the woman maybecome pregnant.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(3)

(iii) IVF clinics have been set a target to reduce multiple births.

At least 76% of IVF treatments should result in single babies anda maximum of 24% of treatments should result in multiple births.

Suggest one reason why the clinics have been set this target to reduce multiplebirths.

______________________________________________________________

______________________________________________________________

(1)


(c) Two clinics, R and S, used IVF treatment on women in 2007. Doctors at each clinic usedthe results of the treatments to predict the success rate of treatments in 2008.

The table shows the information.

Total number of IVFtreatments in 2007

Number of IVFtreatments resulting in

pregnancy in 2007

Predicted percentagesuccess rate in 2008

Clinic R 1004 200 18–23

Clinic S 98 20 3–56

(i) Compare the success rates of the two clinics in 2007.

______________________________________________________________

______________________________________________________________

(1)

(ii) The range of the predicted success rate in 2008 for clinic R is much smaller than therange of the predicted success rate for clinic S.

Suggest why.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(Total 11 marks)


The diagram shows some of the stages in IVF (in vitro fertilisation).

(a) Use words from the box to name structures A, B, C and D.

egg embryo fertilised egg ovary sperm

Structure A ____________________________

Structure B ____________________________

Structure C ____________________________

Structure D ____________________________

(4)

24

(b) What do doctors do next with structure D?

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)


(c) The table gives statistics for an IVF clinic.

Age of women treated

Below 35years

35 – 37years

38 – 39years

40 – 42years

Number of women treated 414 207 106 53

Number of women whoproduced one baby 90 43 17 1

Number of women whoproduced twins 24 8 4 1

Number of women whoproduced triplets 1 0 0 0

(i) About what proportion of the treated women aged 35 – 37 years produced one ormore babies?

Draw a ring around your answer.

one quarter one third half

(1)

(ii) This clinic does not give IVF treatment to women over 42 years of age.

Use data from the table to explain why.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(iii) The committee which regulates IVF treatment now advises that only one embryo isused in each treatment.

Suggest one reason for this.

______________________________________________________________

______________________________________________________________

(1)

(Total 10 marks)


The diagram shows the structures involved in the knee-jerk reflex. When the person is hit at pointP, the lower leg is suddenly raised.

(a) Name the structures labelled A, B and C.

A __________________________________________________________

B __________________________________________________________

C __________________________________________________________

(3)

25

(b) How is information passed across a synapse?

___________________________________________________________________

___________________________________________________________________

(1)

(c) What is the effector in this response?

___________________________________________________________________

(1)

(Total 5 marks)


Diabetes is a disease in which the concentration of glucose in a person’s blood may rise to fatallyhigh levels.Insulin controls the concentration of glucose in the blood.

(a) Where is insulin produced?

Draw a ring around one answer.

gall bladder liver pancreas

(1)

26

(b) People with diabetes may control their blood glucose by injecting insulin.

(i) If insulin is taken by mouth, it is digested in the stomach.

What type of substance is insulin?

Draw a ring around one answer.

carbohydrate fat protein

(1)

(ii) Apart from using insulin, give one other way people with diabetes may reduce theirblood glucose.

______________________________________________________________

(1)


(c) The bar chart shows the number of people with diabetes in different age groups in the UK.

Age in years

(i) Describe how the number of males with diabetes changes between the ages of0 – 44 years and 75 years and over.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(3)


(ii) Compare the number of males and females with diabetes:

between the ages of 0 and 64 years

______________________________________________________________

______________________________________________________________

______________________________________________________________

over the age of 65 years.

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(Total 8 marks)

Penguins live mainly in the Antarctic. Penguins eat mainly fish.Photograph 1 shows a penguin swimming underwater.

Photograph 1

© raywoo/iStock

27


(a) Use information from Photograph 1 to suggest three ways the penguin is adapted forcatching fish.

1. _________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________

3. _________________________________________________________________

___________________________________________________________________

(3)

(b) The Antarctic winter is very cold. In the winter some species of penguin huddle together asshown in Photograph 2.

Photograph 2

© Fuse

Suggest how the behaviour shown in Photograph 2 helps the penguins to survive theAntarctic winter.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)


(c) A student did an investigation to model the behaviour of the penguins shown inPhotograph 2.

The diagram shows the apparatus the student used.

The student:

• held seven similar test tubes together with elastic bands as shown in the diagram

• stood a similar eighth tube in a test tube rack

• filled each of the eight tubes with hot water to the same level

• measured the temperature of the water in tubes A, B and C every 2 minutes for 20minutes.


The table shows the student’s results.

Time inMinutes

Temperature in °C

Tube A Tube B Tube C

0 65 65 65

2 65 65 64

4 65 64 63

6 64 64 62

8 64 63 61

10 64 63 60

12 63 62 59

14 63 62 58

16 63 61 57

18 62 61 56

20 62 60 55

(i) Give two variables that were controlled in the investigation.

1. ____________________________________________________________

2. ____________________________________________________________

(2)

(ii) Describe the patterns the data shows.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)


(iii) How far does the data from the model support the suggestion you made in part (b)?

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(d) Describe how blood vessels help control human body temperature.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(4)


(e) Penguins control their body temperature in similar ways to humans.Scientists investigated changes in body temperature of penguins when the penguins werediving to catch fish.

(i) Graph 1 shows the relationship between the temperature of the muscles moving apenguin’s wings and diving.

The shaded areas show when the penguin was diving.

Graph 1

Time

© Reprinted from Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 135,

P.J. Ponganis,R.P. Van Dam,D.H. Levenson,T. Knower,K.V. Ponganis,G. Marshall, Regional heterothermy and

conservation of core temperature in emperor penguins diving under sea ice, pp 477-487, copyright 2003, with

permission from Elsevier

Suggest an explanation for the changes in temperature inside the muscles movingthe penguin’s wings.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(3)


(ii) Graph 2 shows the relationship between the temperature inside a penguin’s foot anddiving.

The shaded areas show when the penguin was diving.

Graph 2

Time

© Reprinted from Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 135,

P.J. Ponganis,R.P. Van Dam,D.H. Levenson,T. Knower,K.V. Ponganis,G. Marshall, Regional heterothermy and

conservation of core temperature in emperor penguins diving under sea ice, pp 477-487, copyright 2003, with

permission from Elsevier

Suggest an explanation for the changes in temperature inside the penguin’s foot as itdives.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(3)

(Total 22 marks)


The number of cases of Type 2 diabetes in the UK is increasing rapidly.

(a) Describe how insulin and glucagon help control the blood sugar concentration in a healthyperson.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(6)

28

(b) What is Type 2 diabetes?

___________________________________________________________________

___________________________________________________________________

(1)


(c) Body mass index (BMI) is a person’s body weight divided by the square of his or her height.

(i) Graph 1 shows the relationship between BMI and the percentage probability ofdeveloping Type 2 diabetes.

Graph 1

Percentage probability of developing Type 2 diabetes

Suggest an explanation for the relationship between BMI and the risk of developingType 2 diabetes.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)


(ii) Graph 2 shows changes in the number of new cases of Type 2 diabetes in the UK.

Graph 2

Year

Suggest explanations for the trend shown by the data in Graph 2.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(3)

(Total 12 marks)

One factor that may affect body mass is metabolic rate.

(a) (i) What is meant by metabolic rate ?

______________________________________________________________

______________________________________________________________

(1)

29


(ii) Metabolic rate is affected by the amount of activity a person does.

Give two other factors that may affect a person’s metabolic rate.

1. ____________________________________________________________

______________________________________________________________

2. ____________________________________________________________

______________________________________________________________

(2)


(b) Predicted early death is the number of years that a person will die before the mean age ofdeath for the whole population. The predicted early death of a person is affected by theirbody mass.

Scientists have calculated the effect of body mass on predicted early death.

The graph shows the results of the scientists’ calculations.

Ideal body mass

The number of times above or below ideal body mass is given by the equation:

In the UK the mean age of death for women is 82.

A woman has a body mass of 70 kg. The woman’s ideal body mass is 56 kg.

(i) Use the information from the graph to predict the age of this woman when she dies.

______________________________________________________________

______________________________________________________________

______________________________________________________________

Age at death = ___________ years

(2)


(ii) The woman could live longer by changing her lifestyle.

Give two changes she should make.

1. ____________________________________________________________

______________________________________________________________

2. ____________________________________________________________

______________________________________________________________

(2)

(Total 7 marks)

Type 1 diabetes develops when the body does not produce enough insulin.

(a) Which organ produces insulin?

___________________________________________________________________

(1)

30

(b) One treatment for diabetes is to inject insulin.

The table gives the properties of four different types of insulin, A, B, C and D.

Type ofinsulin

Time taken for theinsulin to begin towork in minutes

Time taken for insulinto reach maximum

concentration in theblood in minutes

Time when insulinis no longer

effective in hours

A 15-20 30-90 3-4

B 30-60 80-120 4-6

C 120-240 360-600 14-16

D 240-360 600-960 18-20

(i) Some people with diabetes need to inject insulin just before a meal to stop a bigincrease in blood sugar concentration.

Which type of insulin, A, B, C or D, should these people with diabetes inject justbefore a meal?

_________________________

Give the reason for your answer.

______________________________________________________________

______________________________________________________________

(2)


(ii) A person with diabetes is told to inject type B insulin immediately after breakfast at09.00.The person with diabetes is told to then inject a second type of insulin at lunchtime at12.00.The second type of insulin should keep the blood sugar level under control for therest of the 24 hours.

Which type of insulin, A, C or D, should this person with diabetes inject at lunchtime?

______________________________________________________________

Give the reason for your answer.

______________________________________________________________

______________________________________________________________

(2)

(iii) Apart from injecting insulin, give one other way in which Type 1 diabetes can becontrolled.

______________________________________________________________

(1)

(Total 6 marks)


The pancreas and the liver are both involved in the control of the concentration ofglucose in the blood.

The liver has two veins:

• the hepatic portal vein taking blood from the small intestine to the liver

• the hepatic vein taking blood from the liver back towards the heart.

Scientists measured the concentration of glucose in samples of blood taken from thehepatic portal vein and the hepatic vein. The samples were taken 1 hour and 6 hoursafter a meal.

Graph 1 shows the concentration of glucose in the two blood vessels 1 hour after the meal.

Graph 1

Blood vessel

(a) The concentration of glucose in the blood of the two vessels is different.Explain why.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

31


(b) Graph 2 shows the concentration of glucose in the two blood vessels 6 hours after themeal.

Graph 2

Blood vessel

(i) The concentration of glucose in the blood in the hepatic portal vein 1 hour after themeal is different from the concentration after 6 hours.

Why?

______________________________________________________________

______________________________________________________________

(1)


(ii) The person does not eat any more food during the next 6 hours after the meal.

However, 6 hours after the meal, the concentration of glucose in the blood in thehepatic vein is higher than the concentration of glucose in the blood in the hepaticportal vein.

Explain why.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(3)

(Total 7 marks)

The human body produces many hormones.

(a) (i) What is a hormone?

______________________________________________________________

______________________________________________________________

(1)

32

(ii) Name an organ that produces a hormone.

______________________________________________________________

(1)

(iii) How are hormones transported to their target organs?

______________________________________________________________

(1)


(b) Describe how the hormones FSH, oestrogen and LH are involved in the control of themenstrual cycle.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

(Total 6 marks)

The diagram shows the nervous pathway used to coordinate the knee-jerk reflex.When the person is hit at point P, the lower leg is suddenly raised.

33


(a) Name neurones A, B and C.

A __________________________________________________________

B __________________________________________________________

C __________________________________________________________

(3)

(b) The receptor in the muscle in the leg is sensitive to a stimulus.

Suggest the stimulus.

___________________________________________________________________

(1)

(c) Describe what happens at the synapse during this reflex.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

(Total 7 marks)

The diagram shows the structures involved in a reflex action.

(a) On the diagram, name the structures labelled W, X and Y.

(3)

34


(b) The control of blood sugar level is an example of an action controlled by hormones.

Give two ways in which a reflex action is different from an action controlled by hormones.

1. _________________________________________________________________

___________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(Total 5 marks)


The diagram shows an intra-uterine contraceptive device (IUCD).

The IUCD is put inside the uterus (womb). The IUCD contains a hormone. The hormone diffusesdirectly into the uterus. The supply of hormone in the IUCD lasts for about five years.

The hormone works by:

• causing the cervix to produce a thick plug of mucus

• causing the lining of the uterus to become very thin.

For every 1000 women using the IUCD for one year about 2 women become pregnant. There areabout 10 pregnancies for every 1000 women using the contraceptive pill for one year.

Evaluate the use of the IUCD compared with the contraceptive pill.

Use the information in this question and your own knowledge and understanding.

Remember to give a conclusion to your evaluation.

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

35


_______________________________________________________________________

(4)

(Total 4 marks)


Mark schemes

(a) any two from:

• same result at pH 7 and 7.5orcould be any pH between 7 and 7.5ornot tested at pH 7.25orneed to test at smaller pH intervals (between 7 and 7.5)

• accuracy of result only to nearest 0.5 minutes• no repeats• difficult to determine end point (colour)

2

1

(b) 2.7 / 51

0.54 (units per minute)

allow 0.52 with no working shown for 2 marks1

allow 1 mark for 0.52 or 0.56

(c) (after 10 minutes) solution goes black1

(after 60 minutes) solution stays the sameordoes not go blackorgoes slightly orange

1

(d) steeper curve1

levels off at 11.8 units and before 45 minutes1

(e) no / little sugar produced

allow a correct description of what the graph would look like1

(because at 65 °C) the enzyme will be denatured

allow (because) the enzyme’s shape will be changed

or

(because) the active site is damaged1


(so) will no longer fit the starchor(so) will not be able to catalyse the reaction

1

[11]

(a) pancreas12

(b) (in the) blood(stream)

allow in the (blood) plasma1

ignore dissolved or in solution

(c) any two from:

• concentration rises and falls in both people• concentration is higher at start / always in person with diabetes• concentration rises higher in person with diabetes

allow correct use of figures2

plus any two from:

• concentration rises more rapidly in person with diabetes• concentration stays high for longer in person with diabetes• concentration does not return to starting level during test in person with diabetes,

yet concentration returns to starting concentration by 90 minutes in person withoutdiabetes

• concentration goes below starting concentration only in person without diabetes2

(d) reduce carbohydrate / glucose / sugar in diet1

(so) blood glucose concentration does not increase as much1

(so) there is reduced named effect (of prolonged high blood glucose)

allow reduced short or long term consequences such as tiredness

or

increase urination

or

thirst

or eye / kidney / nerve / heart disease1

[9]

(a) fast reaction to reduce / protect from harm

allow named examples1

3


(b) higher caffeine concentration causes shorter reaction time.

allow converse

ignore ‘faster / slower reaction time’1

(c) Level 3 (5–6 marks):A coherent method is described with relevant detail, which demonstrates a broadunderstanding of the relevant scientific techniques and procedures. The steps in themethod are logically ordered. The method would lead to the collection of valid results.

Level 2 (3–4 marks):The bulk of a method is described with mostly relevant detail, which demonstrates areasonable understanding of the relevant techniques and procedures. The method maynot be in a completely logical sequence and may be missing some detail.

Level 1 (1–2 marks):Discrete relevant points are made which demonstrate some understanding of the relevantscientific techniques and procedures. They may lack a logical structure and would notlead to the production of valid results.

0 marks:No relevant content.

Indicative content• use decaffeinated coffee as control• control volume of coffee• blind trial or do not tell students which coffee they are drinking• left for standard time between drink and test• at least 10 minutes• control start position of ruler• control other factors such as light in the room• same person for different concentrations• repeat for each caffeine concentration• use a range of caffeine concentrations• start with lowest concentration of caffeine• use caffeine solution instead of coffee to control for other ingredients• repeat investigation with more people and calculate means

6

[8]

(a) (76 − 28) × 214

96 (units / h)

allow 96 (units / h) with no working shown for 2 marks1

allow 1.6 units / min for 1 mark

allow answer in range of 94–104

(units / h) for 1 mark

(b) increased blood glucose concentration causes insulin release from pancreas1


which stimulates cells to absorb glucose / sugar from the blood, so blood glucoseconcentration decreases

1

(c) any three from:

at least one advantage and one disadvantage of the system(s)must be given for full marks

allow responses phrased in terms of the meter and injectionsystems

advantages of the new system:

• better control so reduces risk of future health problems

allow fewer low / high blood glucose periods so safer• no need to estimate dose of insulin• less chance of giving too much / little insulin• system works automatically / continuously so no need to test / inject

disadvantages of the new system:

• system is always attached so may restrict activities

allow pump is difficult to hide• pump has to be carried somewhere

allow risk of discomfort• pump will need re-filling• risk of infection

orrisk of tissue damage (at injection site)

• line might come out

accept new system more expensive3

qualified conclusion: a statement as to which system is better with reference to at leastone advantage and one disadvantage

for example, the new system is better because although it is moreexpensive, it works automatically

1

(d) blood glucose concentration goes too low1

blood glucose concentration detected by pancreas1

pancreas releases glucagon1

(glucagon causes) cells to convert to glycogen into glucose1

glucose released into blood1

[13]


(a) Pituitary15

(b)

1

= 150 (%)1

(c) the level in the blood is already higher than it was before point A1

levels hadn’t returned to normal yet (before the next scare)

allow he had already been scared so he was expecting the secondscare

1

(d) increased oxygen to brain / muscles1

increased glucose to brain / muscles1

[7]

(a) A FSH

allow follicle stimulating hormone1

6

B Progesterone1

(b) LH peaks

allow luteinising hormone1

which causes an egg to be released.1


(c) Level 3 (5–6 marks):A detailed and coherent explanation is given, which logically links the role of differenthormones to their use in IVF and a clear explanation of how IVF increases the chance ofa successful pregnancy.

Level 2 (3–4 marks):An attempt is made to link the role of hormones to their use in IVF. The logic used inexplaining how IVF increases the chance of a successful pregnancy may not be clear orlinked to the hormones.

Level 1 (1–2 marks):Discrete relevant points made. The logic may be unclear and links may not be made.

0 marks:No relevant content

Indicative content

Identification of hormones used in IVF:• FSH• LH.

Role of hormones in IVF:• FSH causes eggs to mature• LH causes the eggs to be released.

Effect on chance of successful pregnancy:• high levels of hormones cause many eggs to be matured and released• sperm and eggs are collected and eggs are fertilised (so increased probability

of fertilisation)• fertilised eggs are given time to develop into a small ball of cells• some are transferred into the mother (uterus), to increase the probability of

one successfully implanting.6

[10]

(a) Reflex action17

(b) Feature Label

extra lines from the left negate the mark3


(c) dependent1

(d) 17.0

allow answers in range 17.0–17.3 cm1

(e) 0.5 cm1

(f) 23.51

does not fit the pattern or at least 5 cm higher than the other values1

(g) The results are for the left and right hands of different people1

[10]

(a) in the blood(stream)

allow plasma

ignore dissolved or in solution1

(b) all three plots correct

accept two correct plots for 1 mark2

suitable line drawn1

(c) 1 hour1

8

(d) 230−185identification of steepest part of graph and correct readings taken

1

= 451

(e) line on graph showing extrapolation for person B

correct value read from graph (at 130 mg per 100 cm3)

allow 1 mark for a value of 4.5–5 hours if no extrapolation shown2

[9]

(a) 0.92 = 76.2 × time19


time = 0.92 ÷ 76.21

= 0.012

allow 0.012 with no working shown for 3 marks1

(b) pathway B has two synapses

allow converse for pathway A1

chemicals diffuse across each synapse1

which slows down the impulse1

(c) 140−2031

(d) use the same person for each test1

use left hand and right hand1

use a bigger sample size or more people

allow take more readings with each person1

(e) mean drop distance = (230 + 211 + 279 + 215 + 264) ÷ 5 = 239.81

239.8 mm = 0.2398 m1

mean reaction time =

1

= 0.221

incorrect sig. figs max. 3 marks1

allow 0.221 with no working shown for 4 marks

[14]

(a) products below reactants110

correct energy profile1

activation energy correctly labelled1

energy given out correctly labelled1


(b) 31 (%)1

(c) the products would be above the reactants1

(d) catalysts increase rate of reaction

1 mark for each property

1 mark for each explanation

so products formed in less time

or

catalysts lower activation energy

explanation must be linked correctly to the property to gain the mark

so lowers energy requirements

or

catalysts not used up in the reaction

so only an initial outlay needed

or

only a small amount of catalyst needed

so small initial costmax. 4

(e) Protein1

(f) high temperatures1

extremes of pH1

(g) lactase acts as the lock, lactose is the key (substrate)1

lactase has an active site which will only fit lactose molecules1

so lactase will not work with other molecules1

[16]

(a) 6.1 circled on table (15 °C, test 1)111


(b) 1.8

do not allow 1.831

(c) 16 (minutes)

correct number extrapolated from curve1

(d) 4.0 min – blue / black / purple1

7.0 min – yellow / orange / brown1

(e) The amylase solution had been prepared with water at 95 °C1

(f) Level 3 (5–6 marks):A clear and coherent method is described using logical steps and demonstrating a goodunderstanding of how to improve the validity of the method. The method would lead tothe production of valid results that would give rise to a more valid conclusion.

Level 2 (3–4 marks):The substantive content of a method is present and demonstrates reasonableunderstanding of how to improve the validity but may be missing some detail. The planmay not be in a completely logical sequence but leads towards the measurement ofrate of the reaction.

Level 1 (1–2 marks):Simple relevant statements made, which demonstrate limited understanding of how toimprove the experimental method. The response lacks logical structure and would notlead to the production of valid results or a more precise optimum temperature.

0 marks:No relevant content

Indicative content• conduct at a greater range of temperatures• use temperatures both above and below 40 °C• use smaller temperature intervals to get a more accurate optimum (eg go

up in 2 °C increments)• take samples at smaller time intervals to get a more accurate result for

‘time taken’• control the volume of starch used (eg 5 cm 3)• control the volume of the amylase solution (eg 1 cm 3)• control the temperature (eg using a water bath)• heat the two solutions separately before mixing• control the concentration of the starch solution• control the concentration of the amylase solution

6

[13]


(a) tissue → organ → organ systemone right for 1 mark

three right for 2 marks2

12

(b) Epithelial tissue → covers the outside and the inside of the stomachmore than one line from a tissue = no mark

1

Glandular tissue → produces digestive juices1

Muscular tissue → allows food to be churned around the stomach1

(c) (i) light

ignore dark1

(ii) moving (to the dark)1

(iii) any two from:

• use more woodlice• repeat the experiment• run for a longer time

2

[9]

(a) (i) chemical1

(ii) pituitary gland1

13

(b) 8

allow 9 or 101


(c) (i) any four from:• progesterone starts being produced at 4 weeks / no progesterone before

4 weeks• and then / from 4 weeks increases• oestrogen at constant / low level (from 0) to 20 weeks• and then / from 20 weeks increases• from 20 − 36 weeks level of O rises more steeply than that of Por• P is always higher than 0 from 6 to 36 weeks

if no other marks awarded, allow progesterone and oestrogen bothincrease / rise for 1 mark.

4

(ii) oxytocin1

level of oxytocin increases just before birth1

[9]

(a) homeostasis1

(b) in sequence:

pancreas1

liver1

glycogen

correct spelling only1

glucagon


14

(c) (i) broken down / digested1

further detail eg into amino acids / by enzymes / by proteases1

(ii) diet / eating less sugar / less fat

ignore balanced dietor

ignore ‘dieting’ / slimming diet

exercise

accept pancreas transplant1


(d) (i) sensible suggestioneg (owner’s) smell / sweating / change in owner’s behaviour / dizziness /tiredness

1

(ii) any five from:

allow 1 mark for justified conclusion

do not allow full marks unless at least 1 pro and 1 con.

Pro:• % below normal decreases• % in normal increases• reliable / repeatable / valid data as large number of samples

do not allow accurate / precise• patients express satisfaction.

Con:• may not be reliable as blood glucose measurements for only 5 patients /

survey of only 16 (dog owners)• % above normal increases / dogs are less good at detecting high glucose.

5

(e) glucose in urine of diabetic (and not in the non-diabetic)1

urea and Na+ ions are similar in each / slightly lower in diabetic1

+ any three from:• no protein in either urine sample because protein too large / does not pass

through filter• glucose passes through filter in kidney

ignore glucose is reabsorbed• non-diabetic: the / all glucose is reabsorbed / taken back into blood• diabetic: (too much glucose so) cannot all be reabsorbed• because diabetic has high concentration of glucose in blood• urea and Na+ lower in diabetic because less water is reabsorbed (due to extra

glucose in filtrate).3

[19]

(a) (i) stimulus1

(ii) cytoplasm1

15


(b) (i) ear(s)

in this order only1

eye(s)

accept retina1

skin

ignore extra detail1

(ii) A muscle1

[6]

(a) detect changes in surroundings or detect stimuli

allow any named stimulus for skin1

16

convert information to impulse

allow send impulse to sensory neurones / brain1

(b) (i)

muscle contract(ion)

gland release / secrete /produce chemical /hormone / enzyme

1 mark for each effector

1 mark for each response

response must match type of effector (if given)

ignore examples

ignore relax(ation) / movement for contraction

do not allow expansion for muscles4

(ii) any one from:

• (maintain temperature at which) enzymes work best• so chemical reactions are fast(est)• prevent damage to cells / enzymes

allow prevent enzymes being denatured (by temperature being toohigh)

1

[7]


(a) (i) B1

(ii) D1

(iii) C1

17

(b) (i) insulin1

(ii) pancreas1

[5]

Marks awarded for this answer will be determined by the Quality of Communication (QC) as wellas the standard of the scientific response. Examiners should also refer to the information onpage 5, and apply a ‘best-fit’ approach to the marking.

0 marksNo relevant content.

Level 1 (1 – 2 marks)There is a brief description of kidney function including a mention of pituitary gland orhormones but roles may be confused.

Level 2 (3 – 4 marks)There is a clear description of kidney function in relation to fluctuations in blood waterlevels and the roles of the pituitary gland or hormone is mentioned with correct role.

Level 3 (5 – 6 marks)There is a clear and detailed scientific description of kidney function in relation tofluctuations in blood water levels and of the roles of the pituitary gland and ADH.

examples of biology points made in the response:

• if water content too low, ADH released• from pituitary gland• into the blood• (causing) kidney reabsorbs more water• more concentrated / small volume urine produced• if water content too high, ADH lowered / not produced• less water reabsorbed by kidney• more dilute / larger volume urine produced

full marks may be awarded for detailed description of either waterloss or gain

[6]

18

(a) (i) sensory neurone1

a synapse1

19


(ii) contract1

(iii) not connected to brain / coordinated only by spinal cord1

(iv) automatic / rapid (response)

allow no thinking / faster / less time1

protects body from danger / from damage / from burning1

(b) (i) caffeine decreases reaction time

accept caffeine speeds up / quicker reactions1

(ii) the two sets of results overlap (considerably)

allow use of appropriate numbers – eg 5 of the ‘after’ resultsoverlap with the ‘before’ results

allow ‘wide spread of results’

allow ‘it was just one person’ or ‘it was a small sample’

accept use of one pair of results only – if meaning is clear

accept use of one pair of overlapping results1

(iii) any two sensible suggestions: eg

• more repetitions• perform investigation on several other people• use other (measured) amounts of coffee• use different / more time intervals• other suggested measure of reaction time – eg computer-generated light

flash + time measurement• use pure caffeine or caffeine tablets

2

[10]

(a) sensory neurone120

(b) (i) synapse1

(ii) a chemical1


(c) (What happens to the muscle)

mark both parts of the question together

any one from:

• contraction / contracts

ignore relaxation / relaxes / tenses1

• gets shorter

(How this helps the body)

idea of protection for body (from damage / pain)

eg moves finger / arm away (from pin / stimulus / source of pain)1

[5]

(a) motor

allow efferent / postsynaptic

allow another relay (neurone)1

21

(b) release of chemical (from relay neurone)

allow ecf for ‘motor’ neurone from (a)

allow release of neurotransmitter / named example1

chemical crosses gap / junction / synapse

allow diffuses across

allow chemical moves to X1

chemical attaches to X / motor / next neurone (causing impulse)1

(c) (curare) decrease / no contraction

accept (muscle) relaxes1

(strychnine) increase / more contraction

if no other mark awarded allow 1 mark for (curare) decrease / noresponse and (strychnine) increase / more response

1

[6]

(a) (i) one form of a / one gene

do not allow ‘a type of gene’

allow a mutation of a gene1

22


(ii) not expressed if dominant / other allele is present / if heterozygous

or

only expressed if dominant allele not present / or no other allele present

allow need two copies to be expressed / not expressed if only onecopy / only expressed if homozygous

1

(b) (i) two parents without PKU produce a child with PKU / 6 and 7 → 10

allow ‘it skips a generation’1

(ii) genetic diagram including:

accept alternative symbols if defined

Parental gametes:

6: N and nand 7: N and n

1

derivation of offspring genotypes:

NN Nn Nn nn

allow genotypes correctly derived from student’s parental gametes1

identification: NN and Nn as non-PKU

OR nn as PKU

allow correct identification of student’s offspring genotypes1

correct probability only: 0.25 / ¼ / 1 in 4 / 25% / 1 : 3

do not allow 3 : 1 / 1 : 4

do not allow if extra incorrect probabilities given1

(c) (i) mitosis


(ii) 81


(iii) DNA

allow deoxyribonucleic acid

do not allow RNA / ribonucleic acid1

(d) (i) may lead to damage to embryo / may destroy embryos / embryo cannot giveconsent

allow avoid abortion

allow emotive terms – eg murder religious argument must bequalified

allow ref to miscarriage

allow idea of avoiding prejudice against disabled people

allow idea of not producing designer babies1

(ii) any one from:

• prevent having child with the disorder / prevent future suffering / reduceincidence of the disease

ignore ref to having a healthy child

ignore ref to selection of gender• embryo cells could be used in stem cell treatment

allow ref to long term cost of treating a child (with a disorder)

allow ref to time for parents to become prepared1

[12]

(a) (i) A – pituitary

allow hypothalamus1

23

B – ovary / ovaries1

(ii) in blood (stream)

accept in plasma

ignore dissolved1

(b) (i) FSH and Luteinising Hormone (LH)1

(ii) fertilisedORreference to sperm

1

form embryos / ball of cells or cell division1


(embryo) inserted into mother’s womb / uterus

allow (fertilised egg) is inserted into mother’s womb / uterus1

(iii) any one from:

• multiple births lead to low birth weight

• multiple births cause possible harm to mother / fetus / embryo / baby /miscarriages

allow premature

ignore reference to cost / ethics / population1

(c) (i) any one from:

• almost identical

allow S (slightly) more successful

• both approximately 20%1

(ii) larger numbers (in clinic R) (in 2007)

allow only 98 (in S) (compared to 1004 (in R))1

results likely to be more repeatable (in 2008)

allow more reliable

do not accept more reproducible / accurate / precise1

[11]

(a) A sperm124

B egg1

C fertilised egg1

D embryo1

(b) insert into mother

ignore fertilise / check fertilisation / check viability1

womb / uterus1

(c) (i) one quarter1


(ii) no / little chance of success over 421

reference to table of only two women in the age bracket 40-42 years becamepregnant

the statement ‘only 2 out of 53 40-42 year old women becamepregnant / had babies’ gains 2 marks

1

(iii) so fewer twins / multiple birthsormultiple births more dangerous

1

[10]

(a) A sensory (neurone)

ignore nerve1

25

B motor (neurone)

ignore nerve1

C spinal cord / central nervous system / white matter

accept grey matter1

(b) by chemical / substance

allow transmitter1

(c) muscle

allow extensor

ignore muscle names1

[5]

(a) pancreas

apply list principle1

26

(b) (i) protein

apply list principle1


(ii) any one from:

• (controlling / changing) diet

accept sugar(y foods) / named eg

ignore references to starch / fat / protein / fibre

• exercise

accept example, eg go for a run

• pancreas transplant

accept named drug eg metformin1

(c) (i) increase

ignore reference to women1

then fall1

relevant data quote (for male)

eg max at ages 65–74 or starts at 10 (per thousand) or max at 130(per thousand) or ends at 120 (per thousand)

accept a difference between any pairs of numbers in data set

accept quotes from scale eg ‘130’ or ’130 per thousand’ but not’130 thousand’; to within accuracy of +/- 2 (per thousand)

1

(ii) (between 0 and 64) more females (than males) or less males (than females)

ignore numbers

allow eg females more diabetic than males1

(over 65) more males (than females) or less females (than males)

allow eg males more diabetic than females1

[8]

(a) any three from:

• streamlined shape enables it to swim quickly (to catch fish)• wings (provide power) to move quickly (to catch fish)

allow ‘flippers’• wings used for steering• white underside / dark top acts as camouflage (so prey less likely to see it)• long / sharp beak to catch fish

3

27


(b) any three from:

• reduces (total) surface area of penguins exposed to wind / cold atmosphere• reduced number of penguins exposed (to wind / cold)

accept reference to movement in or out of the huddle

accept outer ones insulate / act as barrier• reducing heat loss

allow reduced cooling• ‘share’ body warmth / heat

3

(c) (i) any two from:

• size of tubes• volume of (hot) water

accept amount of (hot) water• left for same length of time

allow measured at same time intervals• starting temperature

2

(ii) any two from:

• tube alone ( C) lost heat most (rapidly)• tube B intermediate• tube A least (rapidly)

allow correct use of figures for all 3 tubes

ignore just quoting final temperature2

(iii) confirms suggestion

no mark awardedaccept correct answers referring to other suggestions in (b)

since (both outer and inner) tubes in bundle lost heat less rapidly (than ‘stand −alone’ tube)

comparison needed1

penguins in a huddle lose less heat (than single ones)

accept ‘it is the same for penguins’1


(d) if the core body temperature is too high

blood vessels supplying the skin (capillaries) dilate / widen

accept reference to arteries / arterioles but not veins / capillaries

do not accept references to movement of blood vessels

ignore enlarge / expand

reference to skin / surface required only once1

so that more blood flows through the (capillaries) in skin / near surface

reference to ‘more’ needed at least once to gain 2 marks1

and more heat is lost

reference to ‘more’ needed at least once to gain 2 marks1

if the core body temperature is too low

blood vessels supplying the skin (capillaries) constrict / narrow

allow full marks if ‘too low’ given first

if no other marks awarded, allow vasodilation when too warm andvasoconstriction when too cold for 1 mark

1

(e) (i) wings move to provide movement for diving

allow muscles contract / work1

energy (for movement) comes from respiration

do not allow produces / makes / creates energyallow energy comes from / is supplied by / is released by respiration

1

respiration / muscle contraction also releases heat

allow produces heat1

(ii) any three from:

• feet not / less used or no muscle contraction in feet

allow little energy / heat released through respiration in feet

do not allow veins / capillaries• vessels supplying feet constrict / less blood to feet• so temperature in feet cools / decreases• more heat loss from large surface area or rapid flow of cold water over foot

3

[22]


(a) any six from:

• hormone(s) / named produced by pancreas• if blood glucose levels are too high, insulin is produced / released• allowing glucose to move from the blood into the cells / named eg liver• glucose is converted to glycogen• if blood glucose levels fall, glucagon is produced / released• glycogen is converted to glucose• causing glucose to be released into the blood

6

28

(b) diabetes that occurs when the body (cells) do not respond / are less responsive toinsulin

1

(c) (i) higher BMIs due to increase in mass / weight (relative to height) / obesity1

obesity / being overweight / being fat is a (significant) risk factor for Type 2diabetes

allow causes Type 2 diabetes1

(ii) any three from:

• related to described change in diet eg fast foods• and less exercise• which increases the chance of obesity / increases BMI• increased awareness has helped to slow the increase

3

[12]

(a) (i) rate of chemical reactions (in the body)129

(ii) any two from:

• heredity / inheritance / genetics

• proportion of muscle to fat or (body) mass

allow (body) weight / BMI

• age / growth rate

• gender

accept hormone balance or environmental temperature

ignore exercise / activity2

(b) (i) 77

correct answer with or without working gains 2 marks

allow 1 mark for 70 / 56 or 1.25 or 52


(ii) increase exercise

accept a way of increasing exercise1

reduce food intake

accept examples such as eat less fat / sugar

allow go on a diet or take in fewer calories

ignore lose weight

ignore medical treatments such as gastric band / liposuction1

[7]

(a) pancreas

allow phonetic spelling1

30

(b) (i) A1

shortest / quicker time (to work)1

(ii) D1

acts for longest time

mark dependent on D

allow D will last until 09.00 / breakfast / 24 hours1

(iii) diet / exercise

if ‘diet’ is qualified, then will need correct qualification, e.g. ‘lesscarbohydrate / sugar’

accept pancreas transplant / stem cell treatment1

[6]

(a) (concentration high) in the hepatic portal vein is blood with glucose absorbed from theintestine

1

31

concentration is lower in the hepatic vein because insulin1

(has caused) glucose to be converted into glycogen1

or

allows glucose into liver cells

(b) (i) (after 6 hours) most of the glucose has been absorbed from the intestine orfrom food into the blood

1


(ii) because glucagon (made in the pancreas) causes

if biological terms incorrectly spelt they must be phoneticallyaccurate

do not accept glucagon made / produced by the liver1

glycogen to be converted into glucose1

glucose released into blood

allow the liver maintains the correct / constant level of glucose inthe blood

1

[7]

(a) (i) any one from:

• chemical messenger / message

allow substance / material which is a messenger

• chemical / substance produced by a gland

allow material produced by a gland

• chemical / substance transported to / acting on a target organ

• chemical / substance that controls body functions1

32

(ii) gland / named endocrine gland

brain alone is insufficient

allow phonetic spelling1

(iii) in blood / plasma or circulatory system or bloodstream

accept blood vessels / named

do not accept blood cells / named1

(b) each hormone must be linked to correct actionapply list principleignore the gland producing hormone

FSH stimulates oestrogen (production) / egg maturation / egg ripening

ignore production / development of egg1

oestrogen inhibits FSH

allow oestrogen stimulates LH / build up of uterine lining1


LH stimulates egg / ovum release / ovulation

accept LH inhibits oestrogenaccept LH controls / stimulatesgrowth of corpus luteumignore production of egg

1

[6]

(a) ignore nerve / neuron(e) throughout

A sensory

accept afferent1

33

B motor

accept efferent1

C relay

accept intermediate1

(b) stretch

allow pressure / pull / tension (in muscle)

allow a hit at (point) P

ignore pain1

(c) any three from:

• chemical (release)

accept neurotransmitter / acetylcholine

• diffuses (across the gap / synapse)

• transmits impulse / information (across synapse)

allow transmits signal / message

• between neurones / nerve cells / named

if named, must be either sensory / A to relay / C or relay / C tomotor / B

allow ‘to the next neurone‘3

[7]

(a) Y - spinal cord / central nervous system / CNS

do not accept spine

ignore nerve / nervous system / coordinator

ignore grey / white matter1

34


W - receptor / nerve ending

ignore sensory / neurone / stimulus1

X - effector / muscle

allow gland1

(b) any two from: eg

accept reverse argument for each marking point

• reflex action quicker

• effect of reflex action over shorter period

• hormone involves blood system and reflex involves neurones / nerve cells

ignore nervous system / nerves

• reflex involves impulses and hormone involves chemicals

• reflex action affects only one part of the body

ignore involves brain

ignore outside / inside stimuli2

[5]


any three from:

max 2 if only advantages or only disadvantages discussed

ignore ‘side effects’ unqualified

ignore side effects produced by hormones

advantages of IUCD over pill eg

• can’t forget to take it / have to take pill every day

do not allow last 5 years unless qualified

• effect much longer than pill

• more effective in preventing pregnancy

do not allow reference to figures unless qualified

• stops sperm entering uterus

disadvantages of IUCD over pill eg

• pain / uncomfortable / risk of infection / may damage uterus

• prevents fertilised egg developing / ‘embryo rights’

allow kills embryo

• needs replacement by doctor / nurse / professionalor access to IUCD is more difficult than pillor IUCD is harder to come off than pill

3

35

argued conclusion

must include a preference and a reference to both advantages anddisadvantagesor one is better in a given situation but the other is better in adifferent situation

1

[4]


Name: B4 Homeostasis and...

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