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FEAST OR FAMINE: NutritionNotes

NAME:

Specific Aims:

By the end of this section you should be able to:

Know the types and amount of food that makes up a balanced diet Know that balanced diets need to vary with age, sex and activity

Critical Skills:

Interpret dietary information from food diary Calculate the nutritional value of a meal Interpret graphs, diagrams on nutritional information. Review scientific method by doing peanut practical procedure.

Please note: The content on pages 10, 20 and 21 are not to be learnt for

examination purposes (interest only)

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TERMS TO KNOW:

Term DefinitionCellular respiration

(revise)

The process in which organisms obtain energy in the form of ATP

from breaking down food with oxygen and producing carbon dioxideand water as waste.

Metabolism (revise) The sum total of all chemical reactions that take place in the body.

Energy The capacity to do work (biological terms).

Joules The SI unit for measuring energy.

Proteins A large organic molecule made up of single amino acids joined

together. Molecule contains carbon, hydrogen, oxygen and

nitrogen/phosphorous/sulphur atoms (CHON/P/S)

Fats/lipids A large organic molecule made up of glycerol and 3 fatty acids.

Molecule contains carbon, hydrogen and oxygen (CHO). Higher H:O

ratio than carbohydrates.Carbohydrates A large organic molecule made up many simple sugars (glucose,

fructose, galactose). Molecule contains carbon, hydrogen and

oxygen (CHO)

Glucose Simple sugar that makes up carbohydrates such as starch, cellulose

and glycogen.

Glycogen Stored form of glucose in the body.

Fibre It is indigestible cellulose which ends up assisting the digestive

processes.

Nutrient A food or other substance that provides energy or building material

for the survival and growth of a living organism.Macronutrient Nutrients that are required by the body in large amounts.

Micronutrient Nutrients that are required by the body in small amounts.

Vitamins Complex chemical compounds needed for growth and keeping

healthy.

Minerals Simple chemical substances that keep the body functioning properly.

RDA (recommended

daily allowance)

The correct daily proportions of carbohydrates, fats, proteins,

vitamins and minerals.

Balanced diet A diet that sustains your biological systems by supplying adequate

amounts of all of the nutrients your organs and tissues need.

Vegetarianism A type of diet in which meat and usually animal products are notconsumed.

Malnutrition Caused by bad eating usually when too little or too much is eaten.

Obesity A condition caused by the excessive intake of food which is stored as

fat.

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FOOD IS NEEDED TO LIVE

You need food for three main reasons:

For energy For growth To keep the body healthy and functioning correctly

ENERGY:

Food is needed to supply the energy for many body functions such as muscle movement and

keeping a constant body temperature.

GROWTH:

Food is needed to supply the raw materials for cell growth and the replacement of old cells.

KEEPING HEALTHY

Food is needed to keep the cells and organs in your body functioning correctly.

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PRACTICAL PROCEDURE: Determining the energy

content of a peanut

(*Revise the steps of the scientific method.Term 3 notes)INTRODUCTION:

How can we show that a peanut, for example, contains energy? One way is to burn it. When

food is burned the energy contained inside is released as heat. We can use this to find out how

much energy a particular piece of food contains. We burn a piece of food and then measure

the amount of heat it gives off by measuring the increase in temperature of a known quantity

of water. From the rise in temperature of the water we can work out the amount of energy

released by the food. The energy contained in food is measured in kilojoules (kJ). 4.2kJ of

energy is required to raise the temperature of 1kg of water by 1C. So we can work out the

energy content by using the following formula:

Energy in joules = mass of water X rise in temperature ( C) X 4.2

Useful information:

1000J = 1kJ

1Litre of water = 1000cm3= 1kg (therefore 20cm

3= 20g)

INSTRUCTIONS:

You will work in pairs and conduct the burning the peanut practical. Complete the task and answer any necessary questions that follow.

AIM: To determine the energy content (kJ) of 1g of peanut by burning the peanut and then

measuring how much it heats up 20cm3of water.

MATERIALS:

1 X Measuring cylinder

1 X Test tube (boiling tube)

1 X Thermometer

1 X Retort stand

1 X dissecting needle

1 X Bunsen burner

1 X peanut

1 X electronic scale

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METHOD:

1. Measure out 20cm3of water with a measuring cylinder then pour it into a large testtube.

2. Clamp the test tube to a retort stand and put a thermometer in it. Make sure the testtube is secure so that it doesnt slip out of the clamp.

3. Record the initial temperature in table below.4. Weigh a peanut on the electronic scale and record the mass in the table below.5. Stick the peanut onto the pointed end of the dissecting needle.

Be careful when doing this step as the needle has a very sharp point.

6. Set the peanut alight using a Bunsen burner and then place it under the test tube.Do not forget to switch off the Bunsen burner as it is dangerous to leave the flame

unattended.

7. When the peanut stops burning; record the final temperature of the water in the table o8. Call your teacher after you have cleaned up your workspace.

RESULTS:

Table recording the raw data of the burning the peanut practical procedure.

Table showing the change in temperature of 20cm3of water in burning peanut

practical procedure.

Initial Temperature (0

C)Final Temperature (

0C)

Change in Temperature (OC)

(Final temp.Initial Temp)

Mass of peanut (g)

Dissectingneedle

Retort stand

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DISCUSSIONS, ERRORS AND MODIFICATIONS:

DISCUSSION

NOTE: Round your units off to 1 decimal place.

1.

State TWO precautions that need to be taken to ensure the success of thisexperimental procedure and to ensure the safety of the investigator.

2. Calculate the energy (in joules) released from the nut. Use the given formula onpage 4.

3. Convert your answer to kilojoules (divide by 1000).

4. Calculate the amount of energy in 1g of your peanut. Show all your working out.

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ERRORS

Comment on any two possible errors that may have occurred while doing this practical

procedure and how you would correct them for future procedures.

MODIFICATIONS

Suggest a possible hypothesis for any future scientific investigation that youve based on this

scientific procedure of a burning nut.

CONCLUSION (write out a suitable conclusion for this burning peanut procedure):

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FOOD THAT KEEPS US HEALTHY

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the storage form of glucose is called glycogen.

Good fats and bad fats

There are different types of fats. The badfats are saturated and trans-fats and are found in

animal fats. They are called bad fats because they increase the levels of bad cholesterol inthe body and decrease the levels of good cholesterol.

Unsaturated fats are known as good fats as they are essential for growth and the renewing of

cells. They keep the heart and arteries healthy as they promote goodcholesterol and are

needed for normal brain and mental development. Unsaturated fats are found in plant oils

(sunflower, olive, linseed, peanut and avocado).

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Table 1a and 1b: The main vitamins and minerals, what foods they are found in and their

functions in the body.

NOTE: The content of these tables will not be examined.

Table 1a: Some major vitamins

Table 1b: Some minerals

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BALANCED DIET

Table 2: The recommended daily servings for 12 16 year old

Source:(C Dawson, 2008)

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SOME INTERESTING FACTS ABOUT WATER

According to Dr. Jeffrey Utz, Neuroscience, pediatrics, Allegheny University,different people have different percentages of their bodies made up of water.

Babies have the most, being born at about 78%. By one year of age, thatamount drops to about 65%. In adult men, about 60% of their bodies are

water. However, fat tissue does not have as much water as lean tissue. Inadult women, fat makes up more of the body than men, so they have about

55% of their bodies made of water. Thus:

Babies and kids have more water (as a percentage) than adults. Women have less water than men (as a percentage). People with more fatty tissue have less water than people with less

fatty tissue (as a percentage).

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Examine the graph below which shows the different amount s of energy that different people

need every day. Answer the questions that follow:

Source: (The Wellcome Trust , 2011)

QUESTIONS:

1. Who needs the most energy?

2. Why does a teenage boy need more energy than a baby boy?

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3. Why does a breast-feeding woman need more energy than a normal woman?

4. How much more energy per day does an Olympic swimmer need compared to anormal man?

5. How many Big Macs must an Olympic swimmer consume to fulfil his/her dailyenergy requirement (one Big Mac = 1.96MJ)?

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FOOD PYRAMIDS

Fig 1: The old food pyramid

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2. What are the main differences you notice between the old and the new foodpyramids?

3. Is it okay to eat just one type of food? Why or why not?

4. Discuss your diet as it is now (based on your food diary that youve been keeping.Describe three ways in which you can modify your diet so that you eat more

healthily?

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DIETS VARY THROUGHOUT THE WORLD

Fig. 3 Jewish family having dinner

grouped

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MALNUTRITION AND DIETARY SUPPLEMENTS

Source: (C Dawson, 2008)

Fig. 4 Children with Kwashikor

Fig. 6 Steroids are very bad for your body.

Fig. 5 Obesity in children is a huge health risk

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Bibliography

C Dawson, P. H. G. J. H. S., 2008. Spot On Life Sciences Grade 10. In: T. Mcleod, ed. Johannesburg:

Heinemann Publishers (Pty) Ltd.

The Wellcome Trust , 2011. Food and Diet. Big Picture.