Year 12 Topic 1

Revision Booklet

Lifestyle, health and

risk

Fill in how well you know each part of the specification using //

Specification link Before Revision After Revision

Explain the importance of water as a solvent in transport, including its dipole nature.

Distinguish between monosaccharides, disaccharides and polysaccharides (glycogen and starch — amylose and amy-lopectin) and relate their structures to their roles in provid-ing and storing energy (β-glucose and cellulose are not re-quired in this topic).

Describe how monosaccharides join to form disaccharides (sucrose, lactose and maltose) and polysaccharides (glyco-gen and amylose) through condensation reactions forming glycosidic bonds, and how these can be split through hy-drolysis reactions.

Describe the synthesis of a triglyceride by the formation of ester bonds during condensation reactions between glyc-erol and three fatty acids and recognise differences be-tween saturated and unsaturated lipids.

Explain why many animals have a heart and circulation (mass transport to overcome limitations of diffusion in meeting the requirements of organisms).

Describe the cardiac cycle (atrial systole, ventricular systole and diastole) and relate the structure and operation of the mammalian heart to its function, including the major blood vessels.

Explain how the structures of blood vessels (capillaries, ar-teries and veins) relate to their functions.

Describe how the effect of caffeine on heart rate in Daphnia can be investigated practically, and discuss whether there are ethical issues in the use of inver-tebrates.

Describe the blood clotting process (thromboplastin re-lease, conversion of prothrombin to thrombin and fibrino-gen to fibrin) and its role in cardiovascular disease (CVD).

Explain the course of events that leads to atherosclerosis (endothelial damage, inflammatory response, plaque for-mation, raised blood pressure).

Describe the factors that increase the risk of CVD (genetic, diet, age, gender, high blood pressure, smoking and inac-tivity).

Describe the benefits and risks of treatments for CVD (anti-hypertensives, plant statins, anticoagulants and platelet in-hibitory drugs).

Analyse and interpret data on the possible significance for health of blood cholesterol levels and levels of high-density lipoproteins (HDLs) and low-density lipoproteins (LDLs). Describe the evidence for a causal relationship between blood cholesterol levels (total cholesterol and LDL choles-terol) and CVD.

Discuss how people use scientific knowledge about the ef-fects of diet (including obesity indicators), exercise and smoking to reduce their risk of coronary heart disease.

Describe how to investigate the vitamin C content of food and drink.

Analyse data on energy budgets and diet so as to be able to discuss the consequences of energy imbalance, includ-ing weight loss, weight gain, and development of obesity.

Analyse and interpret quantitative data on illness and mor-tality rates to determine health risks (including distinguish-ing between correlation and causation and recognising conflicting evidence).

Evaluate design of studies used to determine health risk factors (including sample selection and sample size used to collect data that is both valid and reliable).

Explain why people’s perceptions of risks are often differ-ent from the actual risks (including underestimating and overestimating the risks due to diet and other lifestyle fac-tors in the development of heart disease).

What topics do you need to work on the most? Write yourself 3 INT’s INT 1: INT 2: INT 3: Circulatory systems

In small unicellular organisms, substances move around slowly by _diffusion____________. Surface area to volume ratio is: _surface area of the organism divided by the volume__________________________________________ _________________________________________________________________________________________________________________________________________. This determines if diffusion alone is sufficient. Diffusion is too slow to move substances round the larger bodies of multicellular organisms. They have a mass transport system_______________________ instead: substances are carried in blood, pumped by a heart. In a _closed____________ circulatory system (e.g. in vertebrates) blood is enclosed in narrow ___blood vessels______________________. This increases efficiency: blood travels faster as a higher pressure is generated. _ valves__________ ensure blood flows in one direction. Complete the diagram:

Fish have a __single circulation______________________________: heart pumps blood to gills for gas exchange, then to tissues and back to the heart. Birds and mammals have a ___double circulation________________________________: right ventricle pumps blood to lungs. Blood returns to the left atrium and then the left ventricle pumps it to the rest of the body. Blood travels round the body faster, delivering nutrients faster, so the animals have a higher metabolic rate. Exam questions:

1. Explain, using the term surface area to volume ratio, why large, active organisms need a specialised surface for gaseous exchange.

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scale:

0.075 mm

A

B C

larger, active organisms have higher demand for oxygen. they have a

small surface area to volume ratio so diffusion is ineffective and slow

in supplying oxygen and removing carbon dioxide.

surface area /

mm2 0.28 3.1 23

volume / mm3 0.02 0.59 11.3

surface area to volume ratio

14:1 5:1

2:1

2) None of the organisms A, B or C has a transport system.

Explain why organisms larger than organism C need to have transport systems.

...large surface area:volume ratio, diffusion is ineffective at delivering nutrients/sub-stances....................................................................................................................

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[3 marks] 3. The diagram below shows a mammal and a unicellular organism. The transport system in mammals is a

double circulatory system driven by a pump (the heart), whilst unicellular organisms have no need for special transport systems.

(i) Explain what is meant by a double circulatory system.

mammal (cat)

X 0.075

unicellular organism

X 300

so a mass transport system is needed

great distance!!!!!!!!

blood flows twice from the heart. once to the body (systemic) and once to the lungs (pulmonary)

.....heart pumps blood ..................................................................................................................

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(ii) Explain two reasons why mammals need a circulatory system whilst unicellular organisms, such as that shown in the diagram, do not.

first reason ......................................................................................................

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second reason................................................................................................

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[4]

[Total 6 marks]

Blood vessels

mammals have a small surface area to volume ratio

so diffusion is ineffective and slow becauswhilst unicellular organisms

have large surface to volume ratio so diffusion is

effective

Arteries and veins contain ___________________: a tough, fibrous protein to make them tough and durable. The artery wall ___________ as blood is pumped in and then _____________ as the heart relaxes. Blood flow is continual and there is a pulse. Contracting ______________ and low ______________ in the chest when breathing in assist blood flow in veins. _______________ prevent backflow. There is no pulse and pressure is low. Complete the table with the properties of each blood vessel

Arteries Veins Capillaries

Label the pictures as an artery, vein or capillary

elastic fibres

stretches relaxes

basement membrane(collagen)

endothelium cell

red blood cell

8 µm

collagen & connective tissue

smooth muscle& elastic tissue

lumen (blood)

0.1-10mm Blood pressure is a measure of the _________________of the blood on the walls of a blood vessel. It is higher in arteries and capillaries than in veins. _______________ blood pressure is highest and occurs when the ventricles contract. Pressure is at its lowest in the arteries when the ventricles relax: ____________ blood pressure. Both are measured, using a __________________________, in mmHg eg 120/80.

collagen & connective tissue

smooth muscle& elastic tissue

lumen (blood)

semilunar valve

0.1-20mm

Any factor which causes arteries or arterioles to constrict will lead to high blood pressure or hypertension. These include:

loss of elasticity with age atherosclerosis adrenaline high salt diet. High blood pressure caused by atherosclerosis leads to a worsening of the condition Exam questions:

1. The table below shows features of arteries, veins and capillaries.

If the statement is correct, place a tick ( ) in the appropriate box and if the statement is incorrect place a cross (X) in the appropriate box.

Feature Arteries Veins Capillaries

Walls permeable

Collagen fibres present in walls

Endothelium present

Series of valves present

(Total 4 marks)

yes yes yes

no yes no

yes yes no

no no yes

Cardiac cycle Figure 1.9 on page 8 of the textbook: make sure you know the structure of the heart. The chambers of the heart (_________and ______________) fill with blood when they relax (_____________) and pump blood out when they contract (_____________). The cardiac muscle making up the atria and ventricles is supplied with blood by the ________________________________.

Complete the table by explaining each stage of the cardiac cycle:

Atrial systole

Ventricular systole

Diastole

Exam questions:

1. The diagram below shows a section of a human heart at a specific stage in the cardiac cycle.

(a) Name the stage of the cardiac cycle shown in the diagram and give two reasons for your choice.

Stage ....................................................................................................... Reason 1............................................................................................................... ...................................................................................................................... Reason 2................................................................................................................ .................................................................................................................(3)

(b) Give one function of each of the parts A and B.

(2)

(Total 5 marks)

2.(a) Cardiac muscle contracts myogenically. Explain what is meant by the term myogenic. ……………………………………………….………………………………………………………………….. ……………………………………………….………………………………………………………………….. ……………………………………………….………………………………………………………………….. ……………………………………………….…………………………………………………………………… (2)

Part

A

B

Function

contracts regularly without getting tired/fatigued

The graphs below show the changes in pressure in the aorta and in the left and right ventricles of the heart, during the cardiac cycle. Time 0 indicates the start of atrial contraction.

(b) Compare the changes in pressure in the left ventricle with those in the right ventricle, giving reasons for

the differences. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………(4)

(c) Compare the changes in the pressure in the aorta with those in the left ventricle, giving reasons for the differences. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………(3)

(d) On the graph of changes in pressure in the aorta and left ventricle, show by means of an arrow when the aortic semilunar valve closes. (1)

(Total 10) 3. Explain what is meant by each of the following terms. (a) The cardiac cycle

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(b) Coronary circulation

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Atheroma and blood clotting

1) Complete the table of key terms

Biological Term Definition

Disease process that leads to coronary heart disease and strokes

Blood clot

Heart attack

Deposit resulting from combination of white blood cells and choles-terol

Hard swelling on inner wall of artery resulting from build up of cal-cium salts and fibrous tissue

Type of blood cell without a nucleus involved with clotting

Soluble plasma protein at start of clotting process

An enzyme that catalyses conversion of a soluble plasma protein into an insoluble protein

Long insoluble strands of protein

A tangled mesh of protein strands with trapped blood cells

Soluble plasma protein converted into fibrin

Atherosclerosis: a disease process where fatty deposits block an artery or increase its chances of being blocked by a blood clot (thrombosis)

How atherosclerosis (‘hardening’ of the arteries) occurs:

Fill in the blank boxes.

In the arteries supplying the heart, this causes a heart attack (myocardial infarction). In the arteries supplying the brain, it causes a stroke. An infarction is when tissue dies due to a lack of oxygen. This is usually the result of a lack of blood – ischaemia. Clotting Blood clots when it flows very slowly, or when blood vessel walls are damaged. A blood clot consists of cells trapped in a mesh of insoluble __________ protein. When platelets come into contact with the vessel wall, they become __________ – they stick to each other and to the collagen in the wall: a ______________ is formed. Platelets stick to damaged tissue. When this happens they release __________________. Thromboplastin reacts with _______________ and vitamin K in the blood and becomes ________________. Activated thromboplastin causes ________________ protein (in the blood) to turn into thrombin. Thrombin causes soluble _________________ pro-tein (in the blood) to turn into insoluble ___________________. Fibrin acts like a giant net, which catches red blood cells and clumps them together in one place. This is what scabs and clots are made from. Thrombin is aided by a chemical called Factor VIII. _________________ is a genetic disease in which people can’t make factor VIII. As a result their thrombin doesn’t work properly and their blood does not clot. Haemophiliacs need to inject factor VIII regularly. It is made by genetically altered hamster cells.

Inflammation occurs – white blood cells move

into the artery wall. They accumulate

cholesterol. A deposit (atheroma) builds up.

Blood pressure increases in narrowed

artery. Positive feedback causes more

damage to endothelial cells.

Draw a diagram to show the chemical cascade that occurs during clotting. You should make sure you understand the roles of thromboplastin, prothrombin, thrombin, fibrinogen and fibrin in this process.

Exam questions:

Data and Risk

_____________ is the probability of occurrence of some unwanted event or outcome.

A time period is always quoted e.g. children in a class having a 1 in 5 (0.2 or 20%) risk of catching head lice in a year. Not all individuals are at risk to the same degree. Risk factors increase the chance of the harmful outcome.

Factors that contribute to health risks include:

heredity

physical environment

social environment

lifestyle and behaviour choices

Two factors are __________________if an increase in one is accompanied by an increase in the other e.g. the num-ber of people suffering sunburn and the amount of ice cream sold. A positive correlation does not necessarily mean that the two are _____________________________! People’s behaviour is affected by the ________________ of risk. They __________________ the risk of something happening if the risk is not under their control, unnatural, unfamil-iar, dreaded, unfair or very small. There is a tendency to __________________ the risk if it has an effect in the long-term future eg health risks associ-ated with smoking. When data is lacking to estimate the risk, the outcome is _________________.

Exam questions:

1) Data on the cholesterol levels and blood pressure for different adult populations in America were collected.

The mean cholesterol level and the percentage of each population with high blood pressure were

calculated. The results are shown in the table below.

Adult population

(ethnic groups)

Mean cholesterol level

/ mg dm–3

Percentage of

population with high

blood pressure (%)

Black and African American 204 40

White American 206 27

Mexican American 205 29

American Indian and Alaskan

Native Statistically unreliable data Statistically unreliable data

(a) There could be a causal link or correlation between high blood pressure and the other variables shown

in the table. Distinguish between the terms causation and correlation.

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(b)(i) Using the information in the table above, describe the relationship between ethnic group, cholesterol

levels and the percentage of the population with high blood pressure.

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(ii) Suggest one reason why the data on the American Indian and Alaskan Native population are described

as statistically unreliable.

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(c) A student concluded from the results for gender, shown in the table below, that higher cholesterol

levels cause lower blood pressure.

Adult population

(gender)

Mean cholesterol level

/ mg dm–3

Percentage of

population with high

blood pressure (%)

Female 207 26

Male 204 30

Using the information in both tables, explain why this is not a valid conclusion.

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(Total 8 marks)

Risks of CVD

Complete the table to show how the following risks may lead to CVD.

Risk factor How this may contribute to CVD

Genetics

Age

Gender

Diet

Blood pressure

Smoking

Lack of exercise

Stress

Alcohol

Exam questions:

1. Coronary heart disease (CHD) is a major cause of death in developed countries, and accounts for over

160 000 deaths each year in the United Kingdom. One of the main causes of CHD is atherosclerosis, a

condition in which lipids and connective tissue build up on the inside wall of blood vessels.

(a) State two consequences of atherosclerosis which may lead to the development of CHD in an individual.

1 .................................................................................................................................

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2 .................................................................................................................................

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(b) The table shows deaths from coronary heart disease as a percentage of all deaths in the United

Kingdom in 1983.

Percentage of all deaths

Age / years Males Females

0–14 4 3

15–24 7 10

25–34 15 14

35–44 37 18

45–54 53 26

55–64 53 37

65–74 53 50

75 and over 51 56

(i) Which two risk factors associated with the development of CHD are indicated in the table?

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(ii) With reference to the data in the table, compare the percentage of deaths from CHD in males and

females.

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(Total 6 marks)

2. The chart below shows the number of deaths from cardiovascular disease per 100 000 population for

men and women in four countries.

(a) Describe the differences in the death rates shown in the chart above.

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(b) One possible reason for the differences in the death rates due to cardiovascular disease between the

different countries is the quantity of fruit and vegetables eaten.

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of

fruit and vegetable consumption on deaths from cardiovascular disease.

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Number

of

deaths

per

100 000

population

1000 –

800 –

600 –

400 –

200 –

0 – – – ––

France Spain England

and Wales

Russia

Women

Men

–

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due

to cardiovascular disease.

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2 ..................................................................................................................................

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(Total 8 marks)

3. Several risk factors influence the onset of coronary heart disease (CHD), including high blood cholesterol

level, high blood pressure and smoking.

The chart shows the effect of combining these three factors on the incidence of CHD.

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors.

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700

600

500

400

300

200

100

0

Incidence

of CHD

per

100 000

people

0 1 2 3

Number of risk factors

b) Explain how each of these risk factors can influence the onset of CHD.

High blood cholesterol ...............................................................................................

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High blood pressure ....................................................................................................

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Smoking ......................................................................................................................

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(Total 9 marks)

4. The graph below shows the mortality rate (number of deaths per 100 000) from coronary heart disease

in people aged between 65 and 74 in Scotland between 1995 and 2001.

(a) Compare the mortality rate from coronary heart disease in males with that of females, between 1995

and 2001.

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(b) The graph shows a change in the number of deaths from coronary heart disease between 1995 and

2001. Suggest three reasons for this change.

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(c) One cause of coronary heart disease is atherosclerosis. Describe how atherosclerosis develops.

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(Total 10 marks)

Treatment/prevention of CVD

Complete the table by explaining how the procedure/drug helps treat CVD

Treatment How it reduces the risk or treats CVD Side effects

Lifestyle changes

Drugs to control blood pressure

Anticoagulants

Platelet inhibitory drugs

Statins

Water

Water is a d__________ molecule which means that one end is slightly negative, (the o__________ atom), and one end is very slightly positive - the h__________ atoms. This has great significance for the properties of water. The separation of electrical charge is called a dipole represented as + and -. This means that water molecules can interact between dipoles and form a network of __________ bonds. Draw a water molecule showing the dipoles and hydrogen bonding: The properties of water include:

It being an excellent s__________ - many materials will dissolve in water because of its d________ nature. It will dissolve i_____ and non-polar compounds.

The change of d____________ with temperature - as water cools below 4oC the molecules arrange themselves in a matrix that occupies m_______ space than that at higher t___________. Ice is frozen at 0oC in this less dense matrix, and therefore f__________ on top of liquid water. In winter this means that rivers etc. freeze from the top down, and the ice acts as an i____________ layer that protects organisms from f____________.

Water is slow to absorb and release heat - its s__________ h______ c_________ is high meaning that fluctua-tions in aquatic environments such as o_________ are small, and this property provides a thermally stable e______________.

Water's latent h______ of v_____________ is high because of weak interactions between molecules called hy-drogen b__________. It requires a lot of heat e_______ to change liquid water into a g___, and of course the reverse in also true.

The biological uses of water:

Liquid water is still available for life on the planet after billions of years.

It acts as a cooling mechanism, particularly useful in m__________ and in the sweating mechanism.

Water is an a____________ molecule and acts as both an acid and a b______. 2H2O = H3O+ + OH-. This means that it is an important medium for biochemical reactions when it acts as a b___________. Water also acts as a reagent in biochemical processes.

Water is a common part of many living processes, e.g. in respiration and photosynthesis.

Water has many other specific uses. In animal’s water is the main constituent of _________ that transports oxygen, food molecules, waste products and other nutrients around the body. The aqueous and vitreous h__________ in the eye are mainly water and the watery a_________ fluid surrounds mammalian embryos. Cerebro-s________ fluid is mainly water and it is a watery liquid between organs inside the body that provides l___________. Lubrication is also provided by the watery s_________ added to food in the mouth and in the s__________ fluid in joints such as the elbow and k_______. The h______________ skeleton of the earth-worm consisting of body cavities filled with water provides it with structural support.

Exam questions:

1. Read through the following account of the properties of water, then write on the dotted lines the most appropriate word or words to complete the account.

Water has the chemical formula ………………………………… . Water molecules are

described as ………………………………….. because they have a slight positive charge

at one end of the molecule and a slight negative charge at the other end. As a result,

individual molecules form ………………………………….. bonds with each other.

Water is an important ………………………………….. in living organisms because

most biochemical reactions take place in aqueous solution. Water also has a high

………………………………….., which means that its temperature remains relatively

stable despite large changes in the temperature of the surrounding environment. (Total 5 marks)

2. Read through the following account of compounds used for energy storage in cells, then write on the dotted

lines the most appropriate word or words to complete the account.

Water is the universal …………………………….. in living organisms. Molecules which dissolve easily in

water can produce osmotic effects. A high concentration of small, soluble molecules within a cell can

cause water .......................………….. the cell. This effect is reduced if the molecules used for storage

in a cell are …………………………….. . Therefore energy storage compounds are usually either

polysaccharides or …………………………….. . Examples of storage polysaccharides include starch and

…………………………….. Starch is found mainly in …………………………….. cells. (Total 6 marks)

3. The table below refers to the formula and structure of some biological molecules.

Complete the table by writing in the name, the formula or the structure of the molecule where appro-priate in the empty boxes.

Name Formula Structure

Water

H2O

Fatty acid

(Total 4 marks)

H C C C C C C

HH

HH

H H H

H H H

O

OH

C

C

CH OH

C C

C

O

OH

H

H

HH

H

OH

OHHO

2

Carbohydrates

Carbohydrates are a large family of compounds with the general formula: __________ Complete the table:

Name of carbo-hydrate

Structure Examples Uses

monosaccharides (monomers)

fructose

galactose

(all the above are hexose sugars: C6H12O6)

disaccharides

maltose

molecules)

sucrose (glucose and fructose)

lactose (glucose and galactose)

polysaccharides (polymers)

starch

glycogen

Cellulose

Make sure you can recognise the structural formulae for glucose, maltose, fructose and galactose molecules – see pages 32 and 33. When monosaccharides join together, they are linked by a __________________. This is formed by a _________________ reaction during which water is given off. Glycosidic bonds are broken in ________________. Water is required for the reaction to take place.

Exam questions:

1. The statements in the table below refer to three polysaccharide molecules. If the statement is correct,

place a tick ( ) in the appropriate box and if the statement is incorrect, place a cross (x) in the

appropriate box.

(Total 4 marks)

Polymer of – glucose

Glycosidic bonds present

Unbranched chains only

Energy store in animal cells

Starch Glycogen CelluloseStatement

2. The table below refers to two organic molecules.

If the statement is correct for the molecule, place a tick ( ) in the appropriate box. If it is incorrect, place

a cross (X) in the appropriate box.

(Total 5 marks)

3. The diagram below shows a carbohydrate molecule formed from two glucose molecules.

(a) Name the molecule shown in the diagram.

……………………………………………………………………………………….(1)

(b) What type of carbohydrate is this?

……………………………………………………………………………………….(1)

(c) Name the type of bond labelled X on the diagram, that links the two glucose molecules.

……………………………………………………………………………………….(1)

(d) Many glucose molecules can be linked together to form cellulose.

(i) State one function of cellulose in living organisms.

…………………………………………………………………..…………….

…………………………………………………………………..…………….(1)

Statement Triglyceride Glycogen

Contains only carbonhydrogen and oxygen

Glycosidic bonds present

Soluble in water

Provides storage of energy

Occurs in flowering plantsand animals

O

O

O

CH OH CH OH2 2

H

OH

Bond X

(ii) Explain how the structure of cellulose is related to its functions.

…………………………………………………………………..…………….

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(Total 6 marks)

4. The table below refers to some disaccharides, their constituent monomers and their roles in living

organisms. Complete the table by writing in the appropriate word or words in the empty boxes.

Disaccharide Constituent monomers One role in living

organisms

Lactose Carbohydrate source in

mammalian milk

Glucose + glucose

Form in which sugars

are transported in plants

(Total 5 marks)

5. The table below refers to two disaccharides, sucrose and maltose. If the statement is correct, place a

tick ( ) in the appropriate box and if the statement is incorrect, place a cross ( ) in the appropriate

box.

Statement Sucrose Maltose

Contains glucose

Is a reducing sugar

Contains glycosidic bonds

Is transported in the phloem

of flowering plants

(Total 4 marks)

6.(a) A student was given two carbohydrate solutions, labelled A and B,

and was told to perform two tests on each solution.

Test 1: Add Benedict’s solution and heat.

Test 2: Add hydrochloric acid and boil.

Neutralise with alkali.

Add Benedict’s solution and heat.

The table below shows the colour of each solution after testing.

Solution Colour after Test 1 Colour after Test 2

A Red

B Blue Red

(i) Complete the table to show what colour solution A would be following Test 2.(1)

(ii) Explain why these results indicate that solution B contained a non-reducing sugar.

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(b) Describe how you would use biuret reagent to compare the concentration of proteins in two solutions.

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(Total 6 marks)

Lipids

Lipids contain the elements carbon, hydrogen and oxygen. They are insoluble in water. They provide twice as much energy as carbohydrates and supply the body with essential fatty acids. Vitamins are often found dissolved in lipids. The most common type are ________________: made up of 3 fatty acids joined to 1 glycerol: When the molecules join together, a _________________ reaction takes place. _____________ bonds are formed. ______________________fatty acids contain the maximum number of hydrogen atoms and no carbon-carbon dou-ble bonds. Found in animal fats and dairy products. ______________________ fats contain 1 double bond e.g. in olive oil. _____________________ fats contain a larger number of double bonds e.g. vegetable and fish oils. If one of the fatty acids in a triglyceride is replaced with a phosphate group, a __________________ is formed. These molecules make up part of the cell membrane. Cholesterol is a short lipid molecule with a structure very different to a triglyceride. Important for cell membranes, sex hormones and bile salts. Found in food, associated with saturated fats.

Exam questions:

1. Read through the following account of the structure and roles of triglycerides, then write on the dotted lines the most appropriate word or words to complete the account Triglycerides are lipids whose molecules are composed of two types of sub-unit, fatty acids and ............................................. held together by .............................................bonds. These bonds are pro-duced when the sub-units are linked together during ............................................. reactions. Triglycer-ides have a number of roles in living organisms, for example ............................................. and ............................................. .

(Total 5 marks)

Glycerol

fatty acid

fatty acid

fatty acid

2. The diagram below shows the structure of a lipid molecule.

(a) (i) Name the parts labelled A and B. A ............................................................................................................ B ............................................................................................................(2) (ii) Name this type of lipid. ................................................................................................................ (1) (iii) Name the chemical reaction used to form the bonds between A and B. ................................................................................................................(1) (b) (i) State one function of this type of lipid in living organisms. ................................................................................................................(1) (ii) State one feature of the molecules of this type of lipid which makes them suitable for the function you have given. ................................................................................................................(1)

(Total 6 marks)

H

C

C

C

H

O

O

O

C

C

C

H

H

H

O

O

O

A B

3. The table below refers to two organic molecules. If the statement is correct for the molecule, place a tick ( ) in the appropriate box. If it is incorrect, place a cross (X) in the appropriate box.

(Total 5 marks)

4. The diagram below shows the general structure of a phospholipid.

(a) (i) Name the parts labelled A and B. A ................................................................................................................ B ................................................................................................................(2) (ii) Name the type of reaction by which the bonds between parts A and B may be broken. ...………………………………………………………………………………(1)

(Total 3)

Statement Triglyceride Glycogen

Contains only carbonhydrogen and oxygen

Glycosidic bonds present

Soluble in water

Provides storage of energy

Occurs in flowering plantsand animals

Organicgroup

P

P

CH

H C O C

H C O C

O

O

H

2

A B

= Phosphate group

Energy budgets and obesity Body mass index (BMI) is a method of classifying body weight relative to height. What is the formula for calculating BMI?

Normal range is around 20. Less than this is underweight and over 30, obese. 20% of the population are obese – excess dietary fat and inactivity are the likely causes. Obesity increases the risk of cardiovascular disease and Type II diabetes. Why might BMI not be the best indicator of obesity? ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Explain alternatives for indicating if someone is over weight: ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Exam questions:

Obesity is a significant problem in western countries and an increasing problem in other parts of the world. An obese

person has a greater risk of developing heart disease.

Body Mass Index (BMI) is one measure used to help decide if a person’s weight is reasonable for their

height. The BMI can be calculated by dividing mass in kilograms by height in metres squared. A table is

then used to judge if the BMI is reasonable or not. A copy of this table is shown below.

BMI range Less than 18.5 18.5 to 24.9 25.0 to 29.9 30.0 to 39.9 40.0 or above

Description Underweight Healthy

weight Overweight Obese

Morbidly

obese

(a) A man was concerned that he was overweight and could be at risk from coronary heart disease. He

was 1.8 m tall and had a mass of 83.0 kg.

(i) Calculate this man’s body mass index (BMI) using the formula below.

BMI =

Answer ...................................................(2)

(ii) Using the information in the table, interpret this man’s BMI.

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................(2)

(b) The graph below shows one analysis of relative mortality compared with BMI, for men and women.

Compare the effect of BMI on relative mortality for men and women.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

2meters)in(heights

skilogrammeinmass

(c)(i) A relative mortality of 1.2 or less indicates a low risk of dying. Using the information given, discuss

whether or not a woman with a BMI of 32.5 should be concerned about her risk of dying.

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................(2)

(ii) Cardiovascular disease (CVD) is responsible for many deaths.

Describe two changes that this woman may be able to make to her lifestyle, to reduce her risk of dying

from CVD. Explain how each change would reduce the risk.

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................(4)

(Total 13 marks)

Mark scheme for exam questions

Circulatory system

1. large / active, organisms have high(er), demand for oxygen / need to remove CO2;

small(er), surface area to volume ratio / SA:V / surface area:volume; surface area too small / distance too large / diffusion takes too long (to supply needs);

ACCEPT ORA throughout IGNORE ref to nutrients

ACCEPT diffusion too slow look for reason why diffusion not good enough

[2]

2.

diffusion not adequate / AW / ora; as not enough area (relative to volume); ora distance too great / cells deep in body / AW; ora, R large unqualified mass flow system needed; transport / blood (vascular), systems, link, the parts of the body / named parts; e.g. of substance needing to be transported; R ‘gases’ / ‘waste’ / ‘food’ ref to activity / high metabolic rate, of mammals; 3 max

3. (i) (blood flows) twice through the heart / AW;

for one circuit / cycle (of the whole body) / AW; A for one heart beat ref pulmonary and systemic systems / to lungs and to (rest of) body; R systematic 2 max

(ii) read whole answer and look for any two linked ideas from

• size

• activity

• SA:V ratio

ora if answered in terms of Paramecium

size (mammals) larger / AW; cells deep in the body; regions requiring materials separated by a distance / need to get materials to all parts / AW;

diffusion too slow / AW;

activity (mammals) more (metabolically) active / AW; need more materials / more rapid supply / more removal of wastes;

SA:V ratio (mammals) surface area:volume ratio reduced / AW; diffusion alone not effective / AW; must be linked to SA:V max 4

Blood vessels

1. The table below shows features of arteries, veins and capillaries.

If the statement is correct, place a tick ( ) in the appropriate box and if the statement is incorrect place a cross (X) in the appropriate box.

Feature Arteries Veins Capillaries

Walls permeable X X

Collagen fibres present in walls

X

Endothelium present

Series of valves present X X

[Total 4 marks]

Heart and cardiac cycle

(a) Name of stage: diastole / atrial systole; Reason 1: aortic / pulmonary artery / semilunar valve(s) closed;

Reason 2: atrioventricular / mitral / tricuspid valve(s) open;

(3 marks)

(b) Give one function of each of the parts A and B.

(2 marks)

[Total 5 marks]

2. (a) Spontaneous / automatic (contraction) / self-stimulating ;

No {nerve impulse / eq} required / no nerve stimulation ; 2

(b) (i) A SAN / sino-atrial node / pacemaker ; B AVN / atrio-ventricular node ; C Bundle of His / Purkyne fibres / Purkinje tissue ; 3

(ii) 1. {SAN / A / pacemaker} initiates impulse / eq ; 2. {Impulse / eq} to {AVN / B} then delay ; 3. So atrial {systole / contraction} before ventricular systole / ventricles fill with blood before systole ; 4. {Bundle of His / C} conducts impulse to (base of) ventricles ; 5. Which contract from {apex / eq} upwards ; 3

[8]

3. The graphs below show the changes in pressure in the aorta and in the left and right ventricles of the heart, during the cardiac cycle. Time 0 indicates the start of atrial contraction.

Part

A

B

Function

prevents valve inverting;

adjusts tension in A/name/contractsto pull on A;

(a) Compare the changes in pressure in the left ventricle with those in the right ventricle, giving rea-

sons for the differences. both rise and fall back to 0 kPa in 0.5 seconds / eq.;

greater change in pressure in left ventricle / smaller changes in right ventricle;

credit correct ref. to figures / range / difference / eq.;

left ventricle contracts more strongly / eq. / right ventricle contracts less strongly eq.;

left ventricle has more cardiac muscle in wall / right ventricle has less;

to pump blood around the body / less distance to lungs / left ventricle pumps blood fur-ther;

so that pressure in the lungs is less;

(4 marks)

(b) Compare the changes in the pressure in the aorta with those in the left ventricle, giving reasons for the differences.

steep / rapid rise in both;

pressure in aorta rises later than in ventricle / starts higher in the aorta;

greater rise in left ventricle / converse / use of figures;

slight time delay in blood passing out of ventricle into aorta;

steeper fall in left ventricle / converse;

gradual fall between 0.4 and 0.8 / 0.9 sec / from 14 / 15 to 10 / 11 kPa is aorta;

caused by elastic recoil of aorta wall;

closure of semilunar / aortic value;

(3 marks)

(c) On the graph of changes in pressure in the aorta and left ventricle, show by means of an arrow when the aortic semilunar valve closes.

arrow placed top of left ventricle curve / cross over point of aorta curve and ventricle curve;

(1 mark)

(d) Cardiac muscle is described as myogenic. Explain how the cardiac cycle is coordinated within the heart.

initiated by sino-atrial node / eq.;

wave of electrical excitation / eq. spreads across atria;

stimulates contraction of (cardiac muscle of) atria;

passes to ventricles via atrio-ventricular node / AVN;

non-conductive tissue / eq. elsewhere between atria and ventricles;

some reference to time delay at AVN;

thus atrial systole occurs before ventricular systole;

excitation / eq. passes down purkinje tissue / bundle of His;

ventricles contract from base / apex;

(4 marks) [Total 12 marks]

4. (a) 1. Rhythmic / sequence (of events) in each heart beat ;

2. {Initiated / controlled} by {pacemaker / SAN (sinoatrial node)} ;

3. Reference to atrial {systole / contraction} ;

4. Reference to ventricular {systole / contraction} ;

5. (complete) diastole / relaxation (of heart) ;

[points 3 to 5 must be in sequence]

(b) Coronary artery ;

From aorta ;

Supplies {blood / oxygen / glucose / nutrients / named nutrient} to heart {muscle / tissue / myocardium} / correct reference to removal of {waste products / named waste product} by coronary circulation ;

Returns to right atrium / coronary sinus / cardiac veins ; 3 [6]

Atheroma and clotting

Data and risk

5. (a) Causation: when a change in one variable is responsible for a change in

another variable / eq;

Correlation:. (relationship between two variables such that) a change in one

of the variables is reflected by a change in the other variable / eq; 2

(b) (i) 1. {no relationship / little difference} between ethnic group and cholesterol level / eq;

2. {more / higher percentage of} black and African Americans have {highest / higher} blood pressure than both White and Mexican Americans / eq; 2

(iii) not enough people surveyed / eq; 1

(c) 1. idea that {other variables present / other variables need considering / no information available about other variables} (for a causal relationship);

2. named variable (e.g. genetics, ethnic group, mass of individuals, age of individuals, diet, smoking, exercise);

3. idea that cholesterol level of 204 mg dm–3 may not be significantly

lower than 207 mg dm–3;

4. idea that {30% may not be significantly different from 26% / two values are not very different};

5. no information on how many tested / survey not repeated elsewhere; 3 max [8]

CVD

1. (a) narrowing of the arteries; thrombosis / blood clot; 2

(b) (i) age and gender; 1

(ii) both increased with age; figures similar 0-34 / over 65; deaths in males greater between 25-74 / converse for females / valid comparison for any age group in this range; males levels off 45 onwards, females rises throughout; 3

[6]

2. (a) 1. Higher death (rate) among men than women in all countries;

2. Highest (rates) of death in Russia / lowest (rates) of death in France;

3. Any valid comparison between countries;

4. Supporting data quoted to back up any valid point;

5. Correct reference to different ratio of men / women death rates between countries; max 3

(b) There is no {difference / correlation} in the death rates between people who eat lots of fruit and vegetables and those who

(c) {don’t eat / eat less} fruit and vegetables / eq; 1

(d) (c) [Paired points - marks for reasons must be linked to a potential difference] 4

Potential difference Reason

1. Different levels of health care; Better treatment / diagnosis / drug availabil-ity / eq;

2. Smoking; Smoking can cause atherosclerosis / carbon monoxide reduces oxygen transport / nico-tine increase blood pressure / eq;

3. {Saturated fat / red meat / eq} intake / converse;

Raises blood cholesterol level / HDL : LDL ra-tio / eq;

4. Lack of exercise; Exercise strengthens heart / eq;

5. Obesity levels; Higher {fat / cholesterol} levels / eq;

6. Levels of stress; Adrenaline / high blood pressure / fast heart rate / eq;

7. Health awareness; Knowledge of risk factors aids preventative action / eq;

8. Poverty / poor living conditions; Affects {diet / health / eq};

9. Alcohol intake; High levels increase blood pressure / {low levels may reduce risk of CHD / red wine an-tioxidants};

10. Age profile of country; CHD increases with age;

11. Genetic differences; Genes may affect health of heart, e.g. hyper-cholesteraemia (gene / allele);

12. Salt intake; High blood pressure;

13. Any valid point; Any valid linked reason;

(e) [8]

(f)

(g)

(h) 3. (a) Increasing the number of risk factors increases risk of CHD;

(i) Increase by one risk factor double incidence / eq;

(j) Adding third risk factor has larger effect on incidence;

(k) Relevant use of manipulated figures; 3

(l)

(b) High blood cholesterol:

1. Fatty deposition in artery walls / plaque formation;

2. Atheroma formed;

3. Increased blood pressure;

4. Lumen of (coronary) arteries narrowed / reduced elasticity of artery wall / eq;

5. Correct reference to LDLs;

High blood pressure:

6. Damage to (lining of) arteries;

7. Risk of aneurysm / damaged lining (of arteries) rupturing;

8. Increased risk of blood clot blocking coronary arteries;

9. Correct reference to inflammatory response;

Smoking:

10. Increases blood pressure;

11. Increases risk of aneurysm;

12. Less antioxidants / more free radicals;

13. Increases {number / activation} of platelets;

14. (Leading to) increased risk of blood clot blocking coronary arteries;

General points [allow in any section]:

15. Reduced blood supply to heart muscle;

16. Angina / increased risk of heart attack;

17. Reference to interactions between factors to increase risk;

18. Correct reference to atherosclerosis; 6 [Maximum 3 marks for each risk factor]

[9]

4. (a) 1. both decrease;

2. mortality rate in men is higher than that in women (throughout time period) / eq;

3. this difference is greater at the start of the time period than at the end / eq;

4. a valid comparison made about the difference in the changes e.g. between 1997 and 1998 the rate stays constant for males but falls for women / fall in mortality rate in men is steeper than the fall in women / decrease in mortality rate is greater in men than women / the decrease in men is less uniform than in women;

5. correct manipulation of figures to quantify any of the above; 3 max

(b) 1. {people more aware of the dangers / better health education} / appropriate named example /eq;

2. less stress /eq;

3. {better / more} screening / eq;

4. better treatments / eq;

5. `more exercise being taken / eq;

6. changed diet / less obesity / eq;

7. less alcohol intake / eq;

8. decrease in smoking;

9. change in population genetics / eq; 3 max

(c) 1. damage to {endothelial cells / epithelial cells /cells lining artery (wall)};

2. reference to inflammatory response;

3. reference to (accumulation of) white blood cells in (damaged area);

4. {build up / eq} of cholesterol (in damaged area);

5. reference to build up of {calcium salts / fibrous tissue / fibrin / platelets};

6. reference to formation of {atheroma / plaque};

7. reference to {loss of elasticity (of artery) / narrowing of lumen} / eq;

8. idea that this process is self–perpetuating; 4 max [10]

(ii) QWC

(QWC – Spelling of technical terms (shown in italics) must be correct and the answer must be organised in a logical sequence)

1. idea that the woman could reduce her {energy / eq} intake;

2. {weight/ BMI} decreases if her energy expenditure greater than intake / eq;

3. diet should have reduced cholesterol levels / eq;

4. cholesterol has been associated with {high blood pressure / atherosclerosis / eq};

5. diet should have reduced saturated fat / eq;

6. reduces blood {cholesterol /LDL} / eq;

7. idea that the woman could increase the amount of exercise she took;

8. weight decreases if energy expenditure is greater than her intake / exercise helps maintain a healthy heart /reduces blood pressure / eq;

9. idea that if the woman smoked she should reduce it;

10. smoking {reduces oxygen uptake / increases stickiness

of platelets / increases blood pressure / increases risk of atheroma / eq};

11. idea that diet should have reduced salt;

12. high salt associated with high blood pressure;

13. idea of moderate alcohol intake;

14. high alcohol associated with high blood pressure; 4 max [13]

Water

1. H2O ;

(di)polar ; Hydrogen / H ; Solvent ; (specific) heat capacity ;

[not latent heat capacity]

[5]

2.

Name of molecule Formula Structure

CH3 (CH2)4 COOH

OR C5 H11 COOH ;

( ) Glucose / hexose ;

C6 H12 O6 ;

3. solvent ;

enter / diffuse into /eq ;

insoluble /osmotically inert / non-polar /eq ; lipids / triglycerides / fats / oils ; glycogen ; plant ; [6] Carbohydrates 1. The statements in the table below refer to three polysaccharide molecules. If the statement is correct, place a tick ( ) in the appropriate box and if the statement is incorrect, place a cross (x) in the appropriate box.

OH H ;

[Total 4 marks] 2. The table below refers to two organic molecules. If the statement is correct for the molecule, place a tick ( ) in the appropriate box. If it is incorrect, place a cross (X) in the appropriate box.

[Total 5 marks] 3. (a) Maltose ; 1 (b) Disaccharide / reducing sugar ; 1 (c) Glycosidic (ignore qualifications, e.g. 1- 4) ; 1 (d) (i) Form plant cell walls / structural support in plants ; 1 (ii) Second mark depends on first, cannot get second mar unless linked to a structural point.

correct structural point ; link to relevant function ;

1. large molecules / many glucoses linked / polymer ;

insoluble ;

2. (forms) straight / unbranched chains ; high (tensile) strength / “strong” forms microfibrils / forms fibres ;

3. cross links / (hydrogen) bonds, between molecules ;

high (tensile) strength / forms mi-crofibrils / forms fibres ;

4. forms microfibrils ; high strength / forms fibres ;

5. (1-4) glucose links ; difficult to digest ;

6. many glucoses linked ; cellulose can be hydrolysed and (glucose) used in respiration ;

max 2 [6]

Polymer of – glucose

Glycosidic bonds present

Unbranched chains only

Energy store in animal cells

Starch Glycogen CelluloseStatement

;

;

;

;

Statement Triglyceride Glycogen

Contains only carbon

hydrogen and oxygen

Glycosidic bonds present

Soluble in water

Provides storage of energy

;

;

;

;

;

;Occurs in flowering plants

and animals

4.

Disaccharide Constituent Monomers One role in living organisms

Glucose and galactose

Maltose Energy / food source in (germinating) seeds

Sucrose Glucose and fructose

[5] 5.

Statement Sucrose Maltose

Contains glucose Is a reducing sugar Contains glycosidic bonds Is transported in the phloem of flowering plants

Encircle CORRECT answers Any TWO correct responses = 1 mark Blanks and ambiguous ticks are incorrect Put correct numbers of ticks to correspond with total mark [4] 6.

Statement Starch Glycogen Cellulose

Polymer of aglucose Glycosidic bonds present Unbranched chains only Energy store in animal cells

[4] 7. (a) (i) Red ; 1 (ii) Test 1 shows no reducing sugar (in solution B) ; In test 2 sugar is hydrolysed / eq ; In test 2 solution (B) was positive ; 2 (b) 1. Add equal volumes of each solution ; 2. To equal volumes of biuret reagent ; 3. {Purple / lilac} colour produced ; 4. Compare intensity of colour / use a colorimeter ; 5. After same period of time ; 3 [6] Lipids

1. The diagram below shows the structure of a lipid molecule.

(a) (i) Name the parts labelled A and B. A glycerol / propan–1, 2,.3–triol;

B fatty acid(s) / fatty acid chain;

(2 marks)

(ii) Name this type of lipid. triglyceride;

(1 mark)

(iii) Name the chemical reaction used to form the bonds between A and B. condensation / esterification;

(1 mark)

(b) (i) State one function of this type of lipid in living organisms. energy store / energy source / insulation / waterproofing / production of metabolic wa-ter / buoyancy / protection;

(1 mark)

(ii) State one feature of the molecules of this type of lipid which makes them suitable for the function you have given.

insoluble / non-polar / high energy value / poor heat conductor / low density / less dense than water;

[points in (b)(ii) need to be correctly linked to the answer given in (b)(i)]

(1 mark) [Total 6 marks]

2. The table below refers to two organic molecules.

If the statement is correct for the molecule, place a tick ( ) in the appropriate box. If it is incorrect, place a cross (X) in the appropriate box.

H

C

C

C

H

O

O

O

C

C

C

H

H

H

O

O

O

A B

[Total 5 marks]

3. (a) (i) A = glycerol 1

B = fatty acid (residue) 1

(ii) hydrolysis 1

(b) polar (molecules) / hydrophilic heads/eq & hydrophobic tails/eq 1 form a bilayer / bimolecular double layer [accept from clear diagram] 1 (polar/hydrophilic) heads outside / (non–polar/hydrophobic) tails inside 1

[6]

3. a- Glycerol

b- Fatty acid

Condensation reaction

5. (a) A Glycerol / propan - 1, 2, 3 - triol B Fatty acid (s) / fatty acid chain 2

(b) Triglyceride 1

(c) Condensation / esterification 1 (d) Energy store or source / insulation /waterproofing /

production of metabolic water / buoyancy / protection; 1

(e) insoluble / non-polar / high energy value / poor heat conductor / low density / less dense than water (points in (e) need to be correctly linked to the answer given in (d)) 1

[6] BMI 6. (a) (i) correct substitution ( e.g. 83 / 1.8 × 1.8);

answer = 25.6;

correct answer = 2 marks 2

Statement Triglyceride Glycogen

Contains only carbon

hydrogen and oxygen

Glycosidic bonds present

Soluble in water

Provides storage of energy

;

;

;

;

;

;Occurs in flowering plants

and animals

(ii) 1. calculated value is 25.6 which is {greater than 25.0 / in range 25.0 to 29.9};

2. (therefore) man is overweight;

3. but only just (overweight); 2 max

(b) 1. relative mortality decreases as BMI increases from 19 to {20 to 23} in (both men and women) / eq;

2. little change in relative mortality within the range {20 / 21 to 24 / 25} / eq;

3. as BMI increases from above {22 to 25} risk increases (in both men and women) / eq;

4. idea that from above {20 to 25} the risk for men is greater than that for women / risk the same between 19 and {20 to 25}; 3 max

(c) (i) 1. (relative mortality is) {1.24 to 1.26};

2. idea that risk is low / no need to be concerned;

3. ref to need to {reduce / be concerned} about {BMI / weight / obesity}; 2 max