8aa1
8Aa1 Testing foods 1

8Aa1 Testing foods 1

 

Name _____________________________        Class ____________

 

Using Skills Sheet 62, do the tests for starch and fat on a variety of different foods. Enter your results in the table below and answer the questions.

 

Recording your results

Fill in this table to show your results.

 

Name of food

Did it contain starch?

Did it contain fat?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Considering your results/conclusions

How did you know if a food contained starch? _________________________________________

 

_______________________________________________________________________________

 

_______________________________________________________________________________

 

How did you know if a food contained fat? ____________________________________________

 

_______________________________________________________________________________

 

_______________________________________________________________________________

 

Can you tell if some foods contain more starch than others? _______________________________

 

How can you tell this? ____________________________________________________________

 

_______________________________________________________________________________

 

Which of your foods contained the most starch? ________________________________________

 

Look up the amounts of starch (carbohydrate) in the foods that you tested. Does your answer above match the information that you have found?

 

_______________________________________________________________________________

 

[ observing, considering, research ]

© Pearson Education Limited 2002 - copyright acknowledged

8aa2
8A2 Testing foods 2

8Aa2 Testing foods 2

 

Sucrose and glucose are both types of sugar. Sugars are types of carbohydrate. Starches are also a type of carbohydrate. However, starch is not a type of sugar. Information like this can be shown on a Venn diagram.

 

Using Skills Sheets 62, 63 and 64 you are going to so some of the tests for starch, protein, fat, glucose and sucrose. Your teacher may tell you which ones to do. You are going to draw a Venn diagram to show your results.

 

Recording your results

1       Draw a table to show which of the foods you tested contain which of the food substances that you tested for.

 

Considering your results/conclusions

 

 

2       Draw a Venn diagram to show which foods contained which food substances. Your diagram might be based on this one.

3       Which food or foods contained the widest variety of different food substances?

 


Evaluation

4       Try to find nutrition information for two or three of the foods that you tested.

a        How well does the nutrition information match your results for each food?

b        Why do you think there may be differences between what is actually in the food and what your tests show?

 

[ knowledge, observing, presenting, considering, evaluating, research ]

© Pearson Education Limited 2002 - copyright acknowledged

8aa3
8A3 True and false foods

8Aa3 True and false foods

 

Name _____________________________   Class ____________

 

1       Write the word 'true' or the word 'false' after each of these sentences.

 

a        Carbohydrates contain a store of energy. _____________________________________

 

b        Proteins are used for growth and repair. _____________________________________

 

c        Meat contains no protein. ________________________________________________

 

d        Fats can be used for energy. _______________________________________________

 

e        Iodine solution can be used to test for sugar. __________________________________

 

f        Two examples of nutrients are fibre and water. ________________________________

 

g        Fats are found in foods like butter, milk and eggs. ______________________________

 

h        It is very important to have an unbalanced diet. _______________________________

 

i         Vitamins and minerals keep our bodies healthy. _______________________________

 

j         Starch is a type of protein. ________________________________________________

 

2       For the sentences that you think are false in Question 1, write out corrected versions on the lines below.

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

3       Here are two lists of words and phrases. Draw lines from the words in the first list to link them to words in the second list. Some of the words in the second list need to be used more than once. Write a phrase above your lines to show what the link is. One has been done for you.

 

 

[ knowledge ]

© Pearson Education Limited 2002 - copyright acknowledged

8aa4
8A4 Food for thought

8Aa4 Food for thought

 

Name _____________________________   Class ____________

 

1       Use the words in the box to complete the sentences.

 

diet        energy        fats        fibre        minerals

nutrients        raw        repair        water

 

         What we eat is known as our ___________________ . Our food provides a source of

 

         ___________________ materials to make new substances.

 

         These new substances are used for:

 

-        ___________________  (to help us to move, etc.)

 

-        growth and ___________________

 

-        health.

 

         Carbohydrates, proteins, ___________________ , vitamins and  ___________________  are

 

         all  ___________________  which means that they provide raw materials.

 

         We also need to eat  ___________________  and drink  ___________________ .

 

 

2       Use the nutrition information label above to answer these questions.

a        How much protein is there in 100 g of the food? ___________________

 

b        How much fat would you get if you ate two of these bars? _______________________

 

          ______________________________________________________________________

 

c        Name one vitamin shown on the label. _______________________________________

 

d        Name one mineral shown on the label. _______________________________________

 

e        Which of the food substances listed helps the rest of your food to pass through your intestines as it is being digested?

 

[ knowledge, numeracy, literacy ]

© Pearson Education Limited 2002 - copyright acknowledged

8aa5
8Aa5 What's in it

8Aa5 What's in it?

 

You will need a copy of Skills Sheet 65 to answers the questions on this sheet.

 

1       Which food contains the most protein per 100 g?

 

2       a        Which food contains the most carbohydrate per 100 g?

b        There are different sorts of carbohydrate. Name one of them.

c        Describe a test you could do for one type of carbohydrate.

 

3       Common salt is a mineral (sodium chloride). We need to have it in our diets but some people need to make sure that they do not eat too much. Name three foods which you would advise someone on a 'low sodium' diet to avoid.

 

4       One substance found in almost all foods is not mentioned in the table. Name it.

 

5       a        Which of the food substances in the table is not a nutrient?

b        Why is this substance important in our diets?

 

6       Teenagers are advised to eat the following amounts of proteins, carbohydrates and fats
each day.

 

Food substance

Amount per day

carbohydrate

300-350 g

fat

60-90 g

protein

50-100 g

 

a        Using the foods on Skills Sheet 65, design a table to show the foods (and the number of grams of each) you would eat to provide these amounts.

b        Explain either why you think your list of foods would be healthy to eat every day or why it would be unhealthy to eat every day.

 

[ knowledge, numeracy ]

© Pearson Education Limited 2002 - copyright acknowledged

8aa6
8A6 RDA

8Aa6 RDA

 

It has been known for a long time that certain foods prevent some diseases. In the 18th century, James Lind discovered that drinking lime juice could prevent scurvy. Scurvy is a disease where your gums bleed, cuts don't heal and your skin bruises easily. However, nobody knew the reason why lime juice prevented scurvy. In 1906 things became a little clearer. In a famous experiment, Frederick Hopkins fed some rats on water and a food containing proteins, fats, carbohydrates and minerals. The rats soon died. He fed another group of rats on the same food but also gave them milk. These rats survived. He came up with a theory that there were 'accessory food factors' in some foods that were needed in the diet. The word vitamin was invented by Casimir Funk in 1912. Since then many vitamins have been identified and we now know how they work. Vitamin C is needed to help wounds heal.

 

Vitamin

RDA

A

800 mg

B1

1.4 mg

B2

1.6 mg

B6

2 mg

B12

1 mg

C

60 mg

D

5 mg

E

10 mg

 

The amount of a vitamin that you need is very, very small. The amounts are measured in milligrams (1 mg = 0.001 g) or even micrograms (1 µg = 0.000001 g). Vitamins have a Recommended Daily Allowance (or RDA). This is the amount that it is recommended for adults to take each day. The amounts are smaller for children. It is dangerous to take too much of some vitamins. Vitamin A is poisonous if you take 10 times too much each day and your hair may start to fall out. Foods do not contain enough vitamin A to harm you, unless you eat polar bear livers!

 

 1      Name a disease that is caused by a lack of a vitamin. The lack of which vitamin causes this?

 

 2      Name the different food substances fed to the rats in Fredrick Hopkins' first experiment and say why each is necessary in the diet.

 

 3      Who invented the word 'vitamin'?

 

 4      Name one vitamin and an organ that you think it might be stored in.

 

 5      Why do you think it might be dangerous to give adult vitamin tablets to young children?

 

 6      Which vitamin do you think you need the most of?

 

 7      What is an RDA?

 

 8      What are the RDAs for these vitamins, in grams:  a  B6;   b  B12;   c  A?

 

 9      How much vitamin A would you have to take to cause damage to yourself?


10     Find out the following information about another vitamin called 'niacin'.

a        The RDA.                     

b        A food that it is found in.         

c        Another name for it.

d        A disease that is caused by a lack of it.

 

[ knowledge, literacy, numeracy, research ]

© Pearson Education Limited 2002 - copyright acknowledged

8ab1
8B1 Newspaper article 1

8Ab1 Newspaper article 1

 

Marketing and advertising: food industry's healthy debate

by Alison Maitland

 


N

ews of a £20 million marketing and advertising campaign by the food industry to persuade customers that British food is safe and healthy has run into criticism from industry observers and consumer groups.

     Verner Wheelock, visiting professor of food science at Nottingham University and an industry consultant, says the campaign is 'a complete waste of time'. Food scares like the beef crisis will continue to plague Britain until the industry adopts a positive approach to health issues, he argues.

     He cites manufacturers' reluctance to cut salt in processed food or to add folic acid to products for pregnant women to help birth defects as examples of the industry missing the chance to improve its image.

     The National Consumer Council agrees that 'the food industry is reluctant to take the bull by the horns and lead on health issues'. Carmen Taboas, food policy officer, says the campaign appears to miss the broader questions raised by recent food scares about whether health problems are caused partly by production methods such as intensive farming. 'It's intensive food production which concerns consumer groups, and whether the new technologies are safe,' she says.

     John Young of the independent Leatherhead Food Research Association believes the advertising campaign 'won't make a jot of difference' because so many food scares are rapidly over. He suggests the campaign could even create unnecessary doubt in people's minds about safety. 'I'm not so sure the consumer has a perception of poor quality of food anyway.'

     Wheelock says a proactive approach by the industry might not boost sales, but nor would it involve a huge advertising budget. 'There are lots of little companies that are trying to take an ethical approach,' he says, citing Baby Organix, the Dorset-based producer of organic baby foods which was set up in 1992 and now supplies leading supermarket groups.

Wheelock's work reflects his interest in health issues. One of his consultancies is with Klinge, a Scottish company that produces LoSalt, a salt substitute, and he is working for J. Sainsbury on developing 'healthy' products.

   He says the government declined to accept a recommendation from its own medical advisers 18 months ago that average sodium intake should be cut by 30 per cent. There were 'strong suspicions that this was under pressure from the food industry'.

   'With something like salt, it wouldn't be all that difficult for [the industry] to make some reduction across the board,' he says. 'They would have had a very positive story to put across about how they're seriously concerned about the health of the nation and are taking action to make a genuine contribution.' Wheelock says Heinz has gradually reduced salt in some of its products, testing this on consumer panels to find out when people taste the difference. 'But rather than being positive, most of the industry has been very negative, trying to pick holes in scientific evidence.'

   Fortifying flour with folic acid - important in preventing spina bifida in babies - is seen by some specialists as a helpful way of ensuring that all women have enough in their diets. Wheelock says this is an 'ideal opportunity' for the bread industry. But the Federation of Bakers told a meeting last year that bakers would not welcome having to add folic acid to bread for the sake of a small proportion of women.

   Supermarkets, which have to deal with customers face-to-face, are very responsive to food scares, Young points out. But trailblazing on health issues can backfire for manufacturers. He cites the case of MD Foods of Denmark, which ran into trouble with the claim that its Gaio yoghurt could cut cholesterol levels. The ASA said this week that the strength of health claims made for some 'functional' foods had begun 'to raise complaints as well as eyebrows'.


 


Source: Financial Times, 13 June 1996. © 1996, The Financial Times Limited. Reproduced with permission.

© Pearson Education Limited 2002 - copyright acknowledged

8ab2
8Ab2 Newspaper article 2

8Ab2 Newspaper article 2

 

Study shakes belief that salt is a risk

 

by Jeremy Laurance

 


S

alt is bad for you - or it may be good for you depending on the latest scientific paper you read. The link between salt and health is thrown into confusion today with the publication of a study suggesting that those who eat least die soonest.

     Previous research has suggested that high consumption of salt increases the risk of early death and current British government advice is to cut consumption by 30 per cent.

     For [the] latest study, researchers at the Albert Einstein College of Medicine in New York examined details of the diets of more than 11 000 people in the United States collected between 1971 and 1975. The participants had been asked to record all they ate in a 24-hour period. The researchers then examined death records for 1992 to see who had died in the intervening 20 years.

     They found that those with the highest salt intake - in the top quarter of the study group - had an 18 per cent lower death rate than those in the lowest group.

     The results, published in The Lancet medical journal, are valuable, according to the researchers, because they link salt intake with eventual death rather than with blood pressure, as other studies have done. The researchers conclude that the results are not strong enough to justify advice to increase salt intake but they also 'do not support current recommendations for routine reduction of sodium consumption'.

     However, British scientists said that the paper contained 'misleading statements and methodological flaws' and said the practice of assessing salt intake on the basis of a 'single dietary recall' was notoriously inaccurate.

     Consensus Action on Salt and Hypertension, a group of scientists concerned with salt and its effect on health who are led by Professor Graham MacGregor of St George's Hospital Medical School in London, said that there was 'overwhelming evidence' that a high salt intake was a major cause of high blood pressure. 'Blood pressure in the most important predisposing factor to strokes and heart attacks, the commonest cause of death in the Western world,' the professor said.

     The Committee on Medical Aspects of Nutrition Policy, set up to advise the Government, recommended in its report on heart disease that average salt intake in the United Kingdom should be reduced from nine grams to six grams a day.

     Most salt is hidden in processed food and the scientists say that more must be done to reduce the salt content and to label it clearly in these foods.


 

Source: The Independent, 14 March 1998. © 1998, Independent Newspapers (UK) Limited. Reproduced with permission.

© Pearson Education Limited 2002 - copyright acknowledged

8ab3
8Ab3 Food wheels

8Ab3 Food wheels

 

1       Cut out the two wheels below, and the parts marked on Wheel 1. 

 

2       Place each wheel over a lump plasticine and push the end of a pair of scissors through the centre of each wheel to make a hole.

 

3       Your teacher will tell you what to write in the spaces on Wheel 2.

 

4       You can now join the two wheels together with a butterfly tag pushed through the holes. Wheel 1 goes on top of Wheel 2.

 

           

                                                                      

© Pearson Education Limited 2002 - copyright acknowledged

8ab4
8Ab4 A Big Burger meal

8Ab4 A Big Burger meal

 

Name _____________________________   Class ____________

 

Answer the questions about this meal.

You can use the words listed below to

help you.

 

carbohydrate

energy

fat

growth and repair

health

minerals

protein           

sugar

vitamins

water

 

1       Name one type of food substance that might be found in each part of the Big Burger meal and say why the body needs it.

 

a        Bread roll                       Food substance: _____________________________________

 

                                                Why the body needs it: _______________________________

 

b        Beef                               Food substance: _____________________________________

 

                                                Why the body needs it: _______________________________

 

c        Tomato                          Food substance: _____________________________________

 

                                                         Why the body needs it: _______________________________

 

2       a        The fries are cooked in oil. What food substance does oil contain? _________________

 

b        What does the body use this for? ___________________________________________

 

3       a        What substance does the cola drink mainly contain? ____________________________

 

b        What other substance does it contain? _______________________________________

 

c        Suggest why this substance might be bad for you if you had too much.

 

          ______________________________________________________________________

 


4       a        If you only ate this meal, do you think you would get enough vitamins?

 

          ______________________________________________________________________

 

b        Explain your answer. ____________________________________________________

 

[ knowledge, literacy ]

© Pearson Education Limited 2002 - copyright acknowledged

8ab5
8Ab5 What's on the menu?

8Ab5 What's on the menu?

 

There are seven things needed for a good diet; carbohydrate, fat, protein, vitamins, minerals, fibre and water. These things are needed for energy, growth and repair, and health. Answer the questions about these three meals.

 

Meal A

Meal B

Meal C

two sausages and a few chips, cola

two fish fingers, peas, carrots, mashed potato, milk

small amount of pasta with beans, lettuce and tomatoes, water

no pudding

apple pie

a pear

 

 

1       a        Which meal would be best for an active, growing teenager?

b        Explain your answer.

 

2       a        Which meal would be best for someone who wants to lose some body mass?

b        Explain your answer.

c        People often say that they are going on a diet. What does the word 'diet' really mean?

 

3       a        Choose one of the meals and say what food substances are missing.

b        What does the body need these substances for?

 

4       a        Name one food from each meal that contains carbohydrates.

b        One type of carbohydrate is sugar. Pick out the one thing from all the meals that you think contains the most sugar.

c        What might happen if you have too much sugar?

 

5          What mineral would you expect to find in milk?

 

[ knowledge ]

© Pearson Education Limited 2002 - copyright acknowledged

8ab6
8Ab6 Balanced diets

8Ab6 Balanced diets

 

Look at this 'food pyramid' and answer the questions below.

 

 

To get a balanced diet, people should eat food from each of these groups every day. People should

aim to eat more from the groups lower in the triangle.

 

1       What is meant by a 'balanced diet'?

2       Here are three meals served in a restaurant.

 

Fish and chips.

The 'Pasta special' is pasta with a creamy sauce containing ham and spinach. It also comes with a side salad.

The 'All Day Breakfast' contains fried eggs, sausages, bacon, bread and butter.

 

a        Explain which one is the best example of a balanced meal and say why.

b        Say what a person who has eaten one of the other meals might have for pudding to help make the meal more balanced.

 

3       Write down what you have eaten today.

a        Is what you have eaten a 'balanced diet'?

b        If it is not, explain what you might change to make it more balanced.

 

[ knowledge ]

© Pearson Education Limited 2002 - copyright acknowledged

8ab7
8Ab7 Salt - good or bad?

8Ab7 Salt - good or bad?

 

Adults who are overweight, smoke, drink too much alcohol, do only a little exercise and have too much salt in their diet are likely to develop high blood pressure. This may lead to heart disease. The following extracts show some different views about salt and how it might be bad for us to eat too much.

 

 

1       Look at the extracts. Copy out a sentence which:

a        contains a fact                 b       contains an opinion              c          contains a claim.

 

2       a        Which source of information do you think is the best for trying to back up an argument?

b        Explain why you think this.

 

3       Do you think there is enough information on this page to support the statement: 'salt is bad for you'? Explain your reasoning.

 

4        a        Look at the article from the website. Why do you think the 'nutrition community' (doctors who advise people on what to eat) criticised this investigation?

b        Do you think that there is enough information given in this article to be able to say that the results of the investigation 'seem to indicate that it's the low salt intake and not the kind of diet that lowers blood pressure'? Explain your reasoning.

c        If you were asked to do this investigation, would you do anything differently? If so, what?

 

[ literacy, considering, evaluating ]

© Pearson Education Limited 2002 - copyright acknowledged

8ab8
8Ab8 The work of a food scientist

8Ab8 The work of a food scientist

 

Food scientists have to work out what substances are in foods and how much of each one is there. They use this information to write nutrition information labels for foods.

 

Imagine that a food scientist has to write a nutrition label for a new food. The first thing to find out is how much sugar is in the food. The fact that sugar is soluble and most of the other major substances are insoluble, can be used to separate the sugar.

 

The amounts of food substances found in the food are shown in the table.

 

Food substance

Amount in 100 g of the new food

sugar

24 g

starch

34 g

protein

 8 g

fat

16 g

fibre

 5 g

 

To work out how much energy the food contains, 1 g of the food is burnt in a piece of equipment called a bomb calorimeter. Inside the bomb calorimeter, the burning food heats up some water. The amount of energy contained in the food can be worked out from the temperature rise of the water. The new food raised the temperature of 100 g of water by 44 °C.

 

1       To separate out the sugar, the food is mixed with water. What process might be used to separate the sugar solution from the rest of the food?

 

2       The food scientist finds some food colourings in the food. What process might be used to separate them?

 

3        a        Use the information on the food label to add up the total mass of substances in 100 g of the food.

b        Why doesn't this total add up to 100 g?

 

4       What percentage of the food is made of carbohydrates?

 

5       Work out the total energy in 100 g of the food using these figures. Show your working.

1 g of carbohydrate can release 17 kJ of energy.

1 g of protein can release 23 kJ of energy.

1 g of fat can release 39 kJ of energy.

 

6       What piece of apparatus can be used to find out the energy content of a food?

 

7       The results of burning the food can also be used to work out the energy content. Use the equation below to help you work out the energy content in kJ/100 g of the food. Show your working.

         Mass of water used  ×  temperature rise  ×  4.2   =   energy content in J/g

 


8        a        Is the figure you calculated in Question 7 higher or lower than the one calculated in Question 5?

b        Try to explain this. (Hint: Think about what else might be in the food which is not a nutrient.)

 

[ knowledge, considering ]

© Pearson Education Limited 2002 - copyright acknowledged

8ac1
8Ac1 A model small intestine 1

8Ac1 A model small intestine 1

 

It is very difficult to do practical work with a real small intestine but we can make a model of how it works. Visking tubing can be used. This has very tiny holes in it that are too small to see.

 

Apparatus

-        Visking tubing         -        Skills Sheets 62 and 64

-        Starch suspension   -        Benedict's solution

-        Water bath              -        Tripod

-        Syringe                    -        Gauze

-        Pipette                     -        Bunsen burner

-        Elastic band             -        Beaker

-        Boiling tubes           -        Heatproof mat

-        Iodine solution         -        Eye protection

-        Boiling tube rack

           

                         Wear eye protection.

 

Method

1       Take some Visking tubing and tie a knot in one end. Using a syringe, carefully add 5cm3 of starch suspension to the tubing.

2       Holding the top of the tubing, wash the outside of it under a tap (to clean off any starch that may have been spilt).

3       Place the tubing inside a boiling tube of water and leave the boiling tube in a warm water bath for 20 minutes.

4       Make a copy of the apparatus above and label it to show what you have done.

5       Using Skills Sheets 62 and 64, test the water outside the tubing for starch and for glucose.

 

Recording your results

1          Did you detect any starch in the water outside the tubing after 20 minutes?

 

Considering your results/conclusions

2       Why do you think you got the results that you did? Think about how big the particles of starch may be compared to the holes in the Visking tubing.

3       In this experiment you built a model. In the model, which part of the apparatus represents each of these parts?

a        the intestine

b        the insides of the intestines

c        the blood flowing around the intestines

 

4       What do you think you could do to the starch to allow it to get out of the tubing?

 

[ observing, considering ]

© Pearson Education Limited 2002 - copyright acknowledged

8ac2
8Ac2 In the guts 1

8Ac2 In the guts 1

 

Name _____________________________   Class ____________

 

1       Label the parts of the digestive system on the diagram below. Use these letters as your labels:

A   - the large intestine

B   - where small, soluble molecules are taken
    into the body (absorbed)

C   - where faeces are stored

D   - this organ contains a strong acid

E    - the gullet

F    - where feeding happens

G   - the anus

 

 

2       The answer to each of these questions in one of the letters in question 1.

 

a        Saliva is produced here.                                                   _________________________

 

b        This is called the small intestine.                                        _________________________

 

c        Faeces are eliminated (or egested) here.                           _________________________

 

d        Food travels from the mouth to the stomach here.             _________________________

 

e        Water is removed from undigested food here.                   _________________________

 

f        This is called the stomach.                                                _________________________

 

g        This is called the rectum.                                                  _________________________

 

3       Enzymes are chemicals that chop up large molecules into smaller ones. There are enzymes in the small intestine. Explain why these are needed.

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

[ knowledge, literacy ]

© Pearson Education Limited 2002 - copyright acknowledged

8ac3
8Ac3 In the guts 2

8Ac3 In the guts 2

 

Name _____________________________   Class ____________

 

1       The phrases in the left-hand column can be linked with those in the right-hand column using another phrase. Complete the middle column with linking phrases. One has been done for you.

 

Feeding (or ingestion)                            is when you put food in your                 mouth.

 

Swallowing                              ____________________________________    gullet.

 

Strong acid                              ____________________________________    stomach.

 

Small molecules                        ____________________________________    small intestine.

 

Water                                      ____________________________________    large intestine.

 

Faeces                                     ____________________________________    rectum.

 

Elimination (or egestion)           ____________________________________    anus.

 

2       The drawing shows a model of the small intestine that can be used to help us to imagine what happens in the small intestine. The small intestine is where food molecules are taken into the body (absorbed). The circles represent food molecules.

 

 

a        Draw a circle around each of the food molecules that will go into the blood.

 

b        Explain why you have selected these molecules. _______________________________

 

          ______________________________________________________________________

 

c        Suggest which molecules the smallest circles represent. __________________________

 

d        What must happen to the other molecules for them to get into the blood?

 

          Use the word enzyme in your answer. ______________________________________

 

[ literacy, knowledge ]

© Pearson Education Limited 2002 - copyright acknowledged

8ac4
8Ac4 Teeth and decay

8Ac4 Teeth and decay

 

 

We use teeth to help us cut through food and grind it up. The incisors and canine teeth help us to bite through food. In large carnivorous animals (like tigers) the canine teeth are much longer and help to kill the prey. The molars and premolars grind up our food to help digestion.

 

The enamel that covers our teeth is extremely hard and helps to protect the teeth from being worn away. However, many people get holes in the enamel. These holes are called cavities. When you eat, some of the food gets stuck to your teeth. Tiny organisms called bacteria eat this food. Together, the bacteria and the stuck food are called plaque. The bacteria grow very quickly if the plaque contains a lot of sugary food. The bacteria produce an acid which attacks the enamel and forms a hole. The hole can get bigger and bigger. If the hole reaches through the enamel, it quickly goes through the dentine and into the pulp. This can be very painful.

 

A dentist can fill in small holes as soon as they appear and it is a good idea to go to the dentist every 6 months. You should also brush your teeth twice a day to remove the plaque. The fluoride in toothpastes helps to keep the enamel strong.

 

1       a        How many teeth do you think an adult should have?

b        Why might an adult have fewer teeth than this?

2       What is plaque?

3       Why do you think large cavities are painful?

4       Using some simple labelled diagrams, explain how a large painful cavity is formed.

5       Why do you think dentists tell us not to eat too many sugary foods?

6       Explain why:

a        most toothpastes contain fluoride

b        most toothpastes are weak alkalis.

7       Find out what a 'wisdom tooth' is.

 

[ knowledge, literacy, research ]

 

© Pearson Education Limited 2002 - copyright acknowledged

8ad1
8Ad1 Amylase action

8Ad1 Amylase action

 

Name _____________________________   Class ____________

 

Amylase is an enzyme found in saliva. It breaks down starch, turning it into a sugar. You are going to investigate how temperature affects how well amylase works.

 

Wear eye protection.

 

Prediction

What temperature do you think the amylase will work best at? Choose from one of these temperatures by ticking one box.

 

0-10 °C          35-40 °C            60-100 °C

 

Explain why you have chosen this temperature. ________________________________________

 

_______________________________________________________________________________

 

Apparatus

-           Iodine solution            -           Spotting tile    -           Six test tubes 

-           Test tube rack            -           Two syringes  -           Pipette

-           Amylase solution        -           Starch suspension      -           Stop clock

-           Beaker of water (to wash out the pipette)

 

1          Using a syringe, put 5 cm3 of the starch suspension into three of the test tubes. Place these tubes into three water baths at different temperatures.

2          Using another syringe, put 1 cm3 of amylase solution into three more test tubes. Place these into the three water baths.

 

 

3          Start the stop clock and time 5 minutes. While you are waiting, use the pipette to add one drop of iodine solution to each well on the spotting tile. Wash out the pipette when you have finished.

4          After 5 minutes, pour the amylase into the starch suspension in each water bath and swirl the tubes to mix the contents.

5          Take one drop from a tube with the starch and amylase in, and add it to a well on the spotting tile. A blue/black colour shows that starch is there. Wash out the pipette before taking each drop and test all three tubes in this way.

6          Reset and start the stop clock.             Repeat step 5 every 2 minutes.             Fill in your results below

 

Recording your results

Use this grid to record your results. Place a tick in the grey boxes if a blue/black colour appeared.

 

Temperature of tube (°C)

Time after adding amylase (mins)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Considering your results/conclusions

At which temperature do you think the amylase was working best? _________________________

 

How do you know this? ___________________________________________________________

 

_______________________________________________________________________________

 

Does this result agree with your prediction? ___________________________________________

 

Explain why you think the amylase works best at this temperature. ________________________

 

_______________________________________________________________________________

 

Evaluation

How would you improve this experiment to find more precisely which temperature amylase works

best at?

 

_______________________________________________________________________________

 

_______________________________________________________________________________

 

[ observing, considering, evaluating ]

© Pearson Education Limited 2002 - copyright acknowledged

8ad2
8Ad2 Amylase in action

8Ad2 Amylase in action

 

Amylase is an enzyme found in saliva. It breaks down starch, turning it into a sugar. You are going to investigate how temperature or pH affects how well

amylase works.

 

Prediction

 1      Write down a prediction. Say what you think will happen and why.

 

Wear eye protection.

 

Planning

 2      Write down a method for your investigation. You may need some of the following apparatus.

 

Apparatus

-        Iodine solution                -        Spotting tile                       -        Test tubes   

-        Test tube rack                -        Syringes                            -        Pipette

-        Amylase solution            -        Starch suspension             -        Stopclock

-        Acid solution                   -        Alkali solution                   -        Eye protection

 

 3      You will also need to think about these questions:

-        Which factors will you vary and which will you keep the same?

-        How will you make sure you do a fair test?

-        How will you find out if the amylase is working?

-        What will you measure?

-        How often will you make measurements?

-        What ranges will you use for the factors you are varying?

-        What will you do to make sure you stay safe?

 4      Show your method to your teacher before you begin.

 

Recording your results

 5      Make a table to record your results.

 

Considering your results/conclusions

 6      Plot a bar chart to show your results.

 7      Using your bar chart, write a 'conclusion'. Say what happened and why you think it happened. Do your results match your prediction?

 

Evaluation

 8      Were any of the results surprising? If so, why?

 9      Did you do a fair test, or were there some factors that you forgot to keep the same?

10     Do you think you have enough results to support your conclusion?

11     How might you improve your experiment?

 

[ planning, observing, considering, evaluating ]

© Pearson Education Limited 2002 - copyright acknowledged

8ad3
8Ad3 A model small intestine 2

8Ad3 A model small intestine 2

 

It is very difficult to do practical work with a real small intestine but we can make a model of how it works. Visking tubing can be used. This has very tiny holes in it that are too small to see.

 

Apparatus

-        Visking tubing                            -        Elastic band

-        Starch solution                           -        Digestive juice solution

-        Water bath                                 -        Boiling tube

-        Two syringes                              -        Iodine solution

-        Benedict's solution                    -        Bunsen burner

-        Gauze                                          -        Tripod

-        Heatproof mat                            -        Beaker

-        Pipette                                        -        Two test tubes

-        Eye protection                            -        Skills Sheets 62 and 64

 

Wear eye protection.

 

Method

1       Take some Visking tubing and tie a knot in one end. Using a syringe, carefully add 5 cm3 of starch solution to the tubing.

2       Using the other syringe, add 1 cm3 of the digestive juice solution.

3       Holding the top of the tubing, wash the outside of it under a tap (to clean off any starch that may have been spilt).

4       Place the tubing inside a boiling tube of water and leave the boiling tube in a warm water bath for
20 minutes.

5       Make a copy of the apparatus below and label it to show what you have done.

 

 

6       Using Skills Sheets 62 and 64, test the water outside the tubing for starch and for glucose.

 


Recording your results

1       What did you find when you tested the water outside the tubing for starch and glucose?

 

Considering your results/conclusions

2       What do the following things represent in your model small intestine?

a        the Visking tubing

b        the liquid inside the tubing solution

c        the water outside the tubing

3       Name one way in which this model is not like a real small intestine.

4       Why do you think the boiling tube was put into a warm water bath?

5       Try to explain your results.

 

[ observing, considering ]

 

© Pearson Education Limited 2002 - copyright acknowledged

8ad4
8Ad4 The digestive system

8Ad4 The digestive system

 

Name _____________________________   Class ____________

 

On the diagram below, write in the name of the organ that each line is pointing to. Use these words:

 

rectum        small intestine        stomach        mouth        gullet        large intestine

 

Now cut out the boxes at the bottom of the page showing the functions of these organs. Stick the correct box underneath the correct organ name.

 

 

-----------------------------------------------------------------------------------------------------------

 

Water is absorbed here.

Faeces are stored here.

Takes food to the stomach.

More enzymes are added here, to complete digestion. The soluble food is absorbed.

Food is ground up here and mixed with saliva which contains an enzyme to digest starch.

The food is churned up with strong acid here and enzymes digest proteins.

 

[ literacy, knowledge ]

 

© Pearson Education Limited 2002 - copyright acknowledged

8ad5
8Ad5 Flicker-book digestion

8Ad5 Flicker-book digestion

 

1       Cut out the pieces along the dotted lines. 2 Put them in order in a pile and staple the top.
3 Flick the pages! 4 Write down what you are observing.

 

 

 

[ literacy, knowledge, observing ]

 

 

© Pearson Education Limited 2002 - copyright acknowledged

8ad6
8Ad6 Digestion 1

8Ad6 Digestion 1

 

Name _____________________________   Class ____________

 

1       Complete the sentences using the words in the box.

 

absorbed        anus        enzymes        intestine       

juices        mouth        insoluble        soluble

 

         Digestion makes  ____________________  substances into ____________________ ones.

This process starts in the ____________________ . During digestion, digestive

____________________  are added to the food. These contain  ___________________ .

When the food that can be digested has been broken down, it is ____________________

by the small  ____________________ . Food that cannot be broken down is passed out

of the body through ____________________.

 

2       For each of the things below, say what it does to help with digestion:

 

The stomach: _____________________________________________________________

 

_________________________________________________________________________

 

Teeth: ___________________________________________________________________

 

__________________________________________________________________________

 

3       Some food cannot be digested. This is called fibre. Write the names of the organs listed in the box in the order that a piece of fibre would go through them.

 

           i  __________________    ii   __________________    iii  __________________

 

          iv __________________    v   __________________    vi  __________________

 

         vii __________________

 

anus        gullet        large intestine        mouth        rectum       

small intestine        stomach

 

[ knowledge, literacy ]

© Pearson Education Limited 2002 - copyright acknowledged

8ad7
8Ad7 Digestion 2

8Ad7 Digestion 2

 

The Fab Food Company make a sandwich called a 'Healthy Delight'. It contains bread, butter, celery and ham.

 

1       Write down the main food substance contained in:

a    bread    b    butter    c     ham.

2       Do you think the 'Healthy Delight' is healthy? Explain your reasoning.

3       'Stringy' vegetables, like celery, contain a lot of fibre. Fibre is not digested by the body. Write down, in order, the names of the organs that the fibre passes through when it is eaten.

4       The table shows the names of some enzymes, what they do and where they are found. Amylase from the salivary gland is destroyed in the stomach and so another amylase is added in the small intestine.

 

Enzyme

Where it's found

What breaks down

amylase

salivary gland

starch

lipase

small intestine

fat

pancreatic amylase

small intestine

starch

pepsin

stomach

protein

trypsin

small intestine

protein

 

a        Where do you think the 'salivary gland' is?

b        Where do you think most digestion happens? Explain your reasoning.

c        Copy the table below. Place ticks in the boxes to show which part of the 'Healthy Delight' sandwich will be digested in the various parts of the digestive system. There can be more than one tick for each food.

 

 

Bread

Butter

Celery

Ham

mouth

 

 

 

 

gullet

 

 

 

 

stomach

 

 

 

 

small intestine

 

 

 

 

 

[ knowledge ]

 

© Pearson Education Limited 2002 - copyright acknowledged

8ad8
8Ad8 Saliva and starch

8Ad8 Saliva and starch

 

Vijay wanted to see how saliva affected starch. He took five test tubes, each containing 5 cm3 of starch suspension. To each one he added 1 cm3 of saliva. He then put the tubes into water baths at different temperatures. Every 10 minutes he took one drop from each tube and mixed it with a drop of iodine solution on a spotting tile and looked for a black colour. His results looked like this:

 

 

1       What substance was Vijay testing for with iodine solution?

2        a        After 40 minutes, the sample taken from the tube at 25 °C did not produce a black colour with iodine. Why do you think this was?

b        What kind of substance in saliva caused this to happen?

3       Draw a graph of Vijay's results. Put temperature on the horizontal axis.

4       a        At what temperature did the saliva appear to have no effect?

b        Why do you think this might be?

5       a        At what temperature did the saliva work fastest?

b        Why do you think this might be?

 

[ knowledge, considering, presenting ]

© Pearson Education Limited 2002 - copyright acknowledged

8ad9
8Ad9 When enzymes attack

8Ad9 When enzymes attack

 

A television company is making a programme called 'When enzymes attack'. In part of the programme the producer wants to explain the process by using people to illustrate what happens. Some people will represent food molecules and others will represent enzymes.

 

The voice-over for this part of the programme has already been written.

 

Programme ID

EN28-ML1

Delivery date

TBC 

Programme name

When enzymes attack

Client

Body TV 

Producer

James Johnson

 

Part

Visuals & Sound FX

Time code

Voice-over script

1

 

00.00

Enzymes are complicated substances. They are made out of proteins and their job is to break apart large food molecules.  

2

 

00.00

Only small food molecules can pass through the wall of the small intestine.  

3

 

00.00

Enzymes break apart the large food molecules into small ones. They basically act like chemical scissors.  

4

 

00.00

This process is called digestion.  

5

 

00.00

Now the new molecules formed by the enzymes can pass through the wall of the small intestine.

 

1       You have been asked to write the 'visuals' for the programme - what people will see happening. For each part of the voice-over script write down how you would use people to show these things.

2       TV programmes need to be carefully timed. When the voice-over artist reads out the script, he or she will watch the film and start to read each part when a certain time is reached. This time is called the 'time code'. It is written out in minutes and seconds. Think how long each of your scenes (1-5) is going to last and then write down the time codes that you want the voice to start at.

3       To make it more interesting you could add some sound effects. Write down any sound effects that you want to use and where you want to use them.

 

Optional extras

4       You may think that the voice-over script is a bit dull. You could try to re-write some of it to make it sound a little more interesting.

5       If you have a video camera you could try to film this part of the programme. You may need:

-        a cast

-        a camera operator

-        a director

-        a person to help organise the people in the cast (properly called a third assistant director)

-        a voice-over artist

-        a sound effects person (properly called a Foley artist).

 

[ literacy, knowledge, numeracy ]

© Pearson Education Limited 2002 - copyright acknowledged

8ae1
8Ae1 Food for life

8Ae1 Food for life

 

Name _____________________________   Class ____________

 

1       Fill in the missing words in these sentences, using the words in the box.

 

blood        carbohydrate        carbon dioxide        lungs        oxygen       

protein        respiration        substances

 

         Some digested food is used in a process called _________________ to provide us with energy.

 

         This process also needs _________________ .  This process releases waste products, like 

 

         _________________  _________________. waste is put back into the  _________________ 

 

         and removed from the body by the _________________. An example of a food substance

 

         used for energy _________________.

 

         Some food is used by the body to make new _________________ for growth and repair.

 

         An example of a food substance used for this is _________________.

 

2       Look at these nutrition information labels.

 

Serious Cereal

Nutrition information

 

Fishy Fillets
Nutrition information

 

Pete's Peas
Nutrition information

Amount per 100 g 

 

Amount per 100 g 

 

Amount per 100 g 

 Energy

          465 kj

 

 Energy

          750 kj

 

 Energy

       127.5 kj

 Carbohydrate

            62 g

 

 Carbohydrate

            14 g

 

 Carbohydrate

              3 g

 Protein

              8 g

 

 Protein

            13 g

 

 Protein

              3 g

 Fat

            21 g

 

 Fat

              8 g

 

 Fat

           0.5 g

 Fibre

              6 g

 

 Fibre

              1 g

 

 Fibre

              3 g

 

a        Which food has the most energy in it? _______________________________________

 

b        Which food has the least energy in it? _______________________________________

 

c        Walking uses 15 kJ per minute. How long would you have to walk for to use up all the energy in 100 g of each food? (Hint: Energy per 100 g ÷ the amount of energy used per minute.)

            i       Serious Cereal ? ____________________________________________________

 

           ii       Fishy Fillets  ______________________________________________________

                                                       

          iii       Pete's Peas  _______________________________________________________

 

[ knowledge, literacy, numeracy ]

© Pearson Education Limited 2002 - copyright acknowledged

8ae2
8Ae2 Digestion concept map 1

8Ae2 Digestion concept map 1

 

This sheet shows some of the key words and ideas about food and digestion. Each box contains an important word. Many boxes are linked by a linking word or a phrase.

 

1       Write down the numbers 1-20 and for each one write down a linking word or linking phrase.

2       From your knowledge, add one more link or an important word with a link to your concept map.

 

 

[ revision ]

© Pearson Education Limited 2002 - copyright acknowledged

8ae3
8Ae3 Digestion crossword

8Ae3 Digestion crossword

 

Name _____________________________   Class ____________

 

Use the clues to fill in the correct words on the grid.

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

3

 

 

 

 

 

 

 

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5

 

 

 

 

6

 

 

 

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8

 

 

 

 

9

 

 

 

 

10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11

 

 

 

12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

13

 

 

 

 

 

 

 

 

14

15

 

 

 

 

16

 

17

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

18

 

 

 

 

 

 

 

 

 

 

 

 

 

19

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

20

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

21

 

22

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

23

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

24

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ACROSS

 3      Food substance used for energy.

 5      The substance that is used in all cells to release energy from.

13     Breathing out carbon dioxide is an example of this life process.

14     Process that cells use to release energy.

19     Calcium is one of these.

20     Food substance that helps clean your intestines.

22     Food substance that is needed for good health.

23     Food is absorbed here.

24     Unit of energy found on food packets.

DOWN

 1      Name of a digestive juice.

 2      Process used to break apart food.

 4      Faeces are stored here.

 6      Organ containing a strong acid.

 

 7      Food substance used for growth and repair.

 8      Tube carrying food from the mouth to the stomach.

 9      Food substance that makes things taste sweet.

10     A product of respiration.

11     Very small tube that carries blood.

12     Food substance stored in the body to provide energy in the future.

13     Substance used to break down food.

15     Getting rid of waste food that cannot be digested.

16     Tube that carries blood away from the heart.

17     Putting food into your mouth.

18     We need to eat a wide variety of foods to get a diet that is ______________.

21     The small intestine is lined with these.

 

 [ knowledge, literacy, revision ]

© Pearson Education Limited 2002 - copyright acknowledged

8ae4
8Ae4 Food absorption

8Ae4 Food absorption

 

Name _____________________________   Class ____________

 

1       The diagram shows how food gets into the body. Label the parts using the words in the box.

 

 

artery        small intestine        starch        sugar        vein        villus

 

2       Explain how the small intestine is adapted to get food into the blood very quickly.

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

         __________________________________________________________________________

 

3       a        In what liquid is food transported around the body? ____________________________

 

b        Name the process that food is needed for, in every cell in the body.

 

         __________________________________________________________________________

 

c        What do cells get from this process?  ________________________________________

 

[ knowledge, literacy ]

© Pearson Education Limited 2002 - copyright acknowledged

8ae5
8Ae5 Digestion concept map 2

8Ae5 Digestion concept map 2

 

Design a concept map to summarise food and digestion. Each important word or important point should be linked to another by a 'linking word' or 'linking phrase'. For example, you might start off your concept map like this:

 

 

You may find these words and phrases helpful but also add some of your own.

 

Some examples of important words and phrases

anus        blood        calcium        carbohydrate        egestion        energy        enzymes        faeces        fat        fibre        growth and repair        gullet        heat insulation        iodine solution        kilojoules        large intestine        making new substances        minerals        mouth        moving        nutrients        producing heat        protein        rectum        respiration        saliva        small intestine        solvent        starch        stomach        store of energy        sugars        vitamin C        vitamins        water

 

Some examples of linking phrases

measured in        released by        small molecules absorbed by        travel in       

travels through these organs        used for

 

[ literacy, knowledge, revision ]

 

© Pearson Education Limited 2002 - copyright acknowledged

8ae6
8Ae6 Eat to live

8Ae6 Eat to live

 

Proteins contain the elements carbon, hydrogen, oxygen and nitrogen. The proteins that we eat are digested into amino acids. Cells inside our bodies use these amino acids to produce new proteins that we need. Muscle cells contain a lot of protein.

 

Fats contain the elements carbon, hydrogen and oxygen. The fats that we eat are digested into fatty acids and another substance called glycerol The body uses these to make different types of fat. Cell membranes contain a lot of fat.

 

Carbohydrates also contain carbon, hydrogen and oxygen but in different proportions to fats. Carbohydrates are digested into small sugars. Glucose is the main sugar that is produced and this is used in respiration. If more carbohydrates are eaten than can be respired, the extra is turned into fat and stored.

 

The word equation for respiration is:

 

glucose + oxygen +                                water + carbon dioxide (+ energy)

 

It can be shown that food is used in respiration by using radioactive markers. One type of carbon is slightly radioactive. Rats fed on glucose containing this sort of carbon are found to breathe out radioactive carbon dioxide!

 

1       a        What are proteins digested into?

b        Name one place in the body where new proteins are made.

2       a        What are fats digested into?

b        Name one place where fats are important.

3       a        What are the reactants in respiration?

b        How do each of these reactants reach the cells?

4       a        What are the products of respiration?

b        Explain how carbon dioxide is excreted from the body.

5       Proteins are not usually used for respiration. Explain how a scientist would show that proteins are not used in respiration.

 

[ knowledge, literacy ]

© Pearson Education Limited 2002 - copyright acknowledged

8ae7
8Ae7 Surface area

8Ae7 Surface area

 

The small intestine can be represented as a tube. In adults this is 6.5 m long and has a diameter of 2.5 cm. The surface area is given by this formula:

 

Surface area of a tube = 2prh

p = 3.142          r = radius   

h = height or length

 

 

 

1       What is the radius of the small intestine in metres (m)?

2       Work out the surface area of the small intestine in square metres (m2). Show your working.

3       The villi increase the surface area by 20 times. Work out the surface area of the small intestine with villi.

4       Each villus is made of a single layer of cells all of which have microvilli on them.

         The microvilli increase the surface area by another 300 times. Work out the surface area of the small intestine, taking both villi and microvilli into account. Show your working.

 

                A villus

 

5       Difficult! Work out how long the small intestine would have to be if there were no villi or microvilli. Show all your working.

6       A disease in humans, called Coeliac disease, causes the villi in the small intestine to get smaller. People with the disease start to become weak and ill. Explain why this might be.

 

[ knowledge, numeracy ]

© Pearson Education Limited 2002 - copyright acknowledged

8asumm
8A Summary Sheets

8A Summary Sheets

 

Food and digestion

 

We need to eat a wide variety of foods to provide our bodies with all the substances that are needed. When we do this, we are said to have a balanced diet.

 

Substance needed

Examples

Why it's needed

Good sources

carbohydrate

starch, sugars

for respiration to release energy

pasta, bread

protein

 

for growth and repair

meat, beans

vitamins

vitamin C

for health

fruits and vegetables - oranges contain a lot  vitamin C

minerals

calcium

for health

fruits, vegetables and dairy products - milk contains a lot of calcium

fibre

 

for health; helps to keep our intestines clean stop them getting blocked up (constipation)

wholemeal bread

water

 

for health; water is important solvent in the body

 

 

We can do tests to find out which substances are in foods. For example, starch makes iodine solution go a blue-black colour.

 

Nutrition information labels on foods tell us what the food contains. The labels also tell us how much chemical energy is stored in the food. The amount of energy is measured in kilojoules (kJ).

 

Eating too much of some foods can cause problems. Too much fat may cause heart disease.

 

To make use of the food, our bodies need to break it up into smaller sized molecules. This is called digestion. Digestion turns large insoluble substances into small soluble ones. The organs of the digestive system help us digest food. Many of them produce enzymes (chemicals that break up food).

 


 

To help absorb the digested food, the small intestine is covered with villi. These increase the surface area.

 

The digested food substances are carried around the body in the blood. The blood travels through blood vessels. Arteries carry blood away from the heart and veins carry blood towards the heart. The smallest blood vessels are capillaries. Substances enter and leave the blood through capillaries. Cells get the substances they need from the blood in capillaries.

 

Cells need food substances to:

 

-        release energy

-        make new substances.

 

Cells use a chemical reaction called respiration to release energy from a sugar called glucose.

 

© Pearson Education Limited 2002 - copyright acknowledged

8atarget
8ATarget sheet

8ATarget sheet

 

Name _____________________________   Class ____________

 

 

Topic

 

Targets

Before the unit

I have learned this

I have revised this

8Aa

1

Know what nutrients and other substances are found in food.

 

 

 

 

2

Know how to test for some food substances.

 

 

 

 

3

Know why water is important.

 

 

 

 

4

Know why fibre is important.

 

 

 

8Ab

1

Know what a balanced diet is.

 

 

 

 

2

Know why some people need more food than others.

 

 

 

 

3

Know which foods contain what substances.

 

 

 

 

4

Know what the food substances are needed for.

 

 

 

8Ac

1

Know the where the organs in the digestive system are.

 

 

 

 

2

Know the functions of the organs in the digestive system.

 

 

 

 

3

Know why food needs to be digested.

 

 

 

 

4

Know what breaks down food.

 

 

 

8Ad

1

Know where digested food is taken into the body.

 

 

 

 

2

Know how to use a model to illustrate digestion.

 

 

 

 

3

Know that enzymes are affected by temperature.

 

 

 

 

4

Know that enzymes are affected by pH.

 

 

 

8Ae

1

Know how digested food is taken into the body.

 

 

 

 

2

Know how digested food is carried around the body.

 

 

 

 

3

Know how digested food is used.

 

 

 

 

4

Know the names and jobs of the blood vessels in the circulatory system.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

© Pearson Education Limited 2002 - copyright acknowledged

8aword
8A Word sheets

8A Word sheets

 

Word sheets that include new words from the 'Focus on:' pages are available on the Exploring Science website.

 

 

8Aa - On a diet

 

Word

Pronunciation

Meaning

constipation

con-stip-ay-shun

When the intestines get blocked up.

diet

 

The food that you eat.

fibre

feye-ber

Substance found in food which cannot be used by the body. It helps to keep our intestines clean.

nutrition information

new-trish-un

Information label found on a food packet to tell you what is in the food.

nutrients

new-tree-ents

Substances needed in the diet to provide raw materials.

raw materials

 

Substances used to make other substances out of.

solvent

 

A liquid that can dissolve other substances.

starch

 

Type of insoluble carbohydrate found in plants.

water

 

A compound made of hydrogen and oxygen which the body uses as a solvent.

 

 


8Ab - Keeping it balanced/Different diets

 

Word

Pronunciation

Meaning

balanced diet

 

Eating a wide variety of foods to give us all the things that we need.

carbohydrate

car-bO-high-drate

Substance found in food that is used for energy.

chemical energy

 

Energy stored in chemicals like food.

fat

 

Substance found in food that is stored to be used for energy in the future. It also helps to keep heat in our bodies.

heart disease

 

Disease caused by narrowing of the arteries carrying the blood to the muscles of the heart, so the heart muscles do not receive enough oxygen.

kilojoule (kJ)

kill-O-jool

Unit of energy used on food packets. There are 1000 J in 1 kJ.

mineral

 

Properly called a 'mineral salt' and found in food. Needed in small quantities for health (e.g. calcium).

protein

 

Substance found in food that is used for growth and repair.

starch

 

Type of insoluble carbohydrate found in plants.

sugar

 

Type of soluble carbohydrate. Glucose is an example of a sugar.

vitamin

 

Substance found in food that is needed in small quantities for health (e.g. vitamin C).

 

 


8Ac - You've got guts

 

Word

Pronunciation

Meaning

absorbed

 

When soluble substances go through the wall of the small intestine into the blood.

anus

 

The opening at the end of the gut.

appendix

 

Small tube branching off the large intestine. It has no function in humans.

contract

 

Something gets smaller.

digestion

dye-jes-jun

Process that breaks food into soluble substances in our bodies.

digestive juices

 

A liquid containing enzymes that break down food.

digestive system

 

A group of organs that carry out digestion.

egestion

ee-jes-jun

When faeces are pushed out of the anus.

enzyme

 

A chemical that can break up large molecules.

Word

Pronunciation

Meaning

faeces

fee-sees

Waste food material produced by the intestines.

feeding

 

Putting food into your mouth. Also called ingestion.

fibre

feye-ber

Substance found in food which cannot be used by the body. It helps to keep our intestines clean.

gullet

 

Tube that goes from the mouth to the stomach. Sometimes called the 'food pipe' but properly called the oesophagus.

gut

 

All the organs of the digestive system apart from the mouth.

ingestion

in-jes-jun

Putting food into your mouth.

insoluble

 

Something that does not dissolve is said to be insoluble.

large intestine

 

Organ that takes water out of waste food.

molar

 

Grinding tooth at the back of the mouth.

rectum

 

Organ that stores faeces before they are egested.

saliva

sall-eye-va

A digestive juice. It contains an enzyme that breaks down starch into sugar.

salivary gland

sall-eye-vor-ee

Found in the mouth. It makes saliva.

small intestine

 

Organ where most digestion happens. The soluble substances produced by digestion are absorbed into the body here. It is about 6.5 m long in adults.

stomach

stum-uck

Organ containing strong acid which mixes food up and digests proteins.

 

 


8Ad - Break down

 

Word

Pronunciation

Meaning

absorbed

 

When soluble substances go through the wall of the small intestine into the blood.

amylase

am-e-laze

An enzyme found in saliva that breaks starch down into sugar.

digestive juice

 

A liquid containing enzymes that break down food.

 

 

8Ae - In the blood

 

Word

Pronunciation

Meaning

absorbed

 

When soluble substances go through the wall of the small intestine into the blood.

artery

 

Blood vessel that carries blood away from the heart.

blood

 

Liquid that flows around the body carrying various substances which are either made by the body or needed by the body.

blood vessel

 

Tubes in which blood flows. There are capillaries, veins and arteries.

capillaries

cap-pill-arr-ees

Tiny tubes that carry blood.

circulatory system

 

System containing the heart and blood vessels.

heart

 

Organ that pumps blood around the body.

respiration

ress-per-ay-shun

Process that uses up oxygen to release energy from food. Carbon dioxide is produced as a waste gas.

tissue

 

A group of cells of the same type all doing the same job.

tissue fluid

 

A liquid that leaks out of capillaries carrying dissolved food and oxygen to cells.

vein

vane

Blood vessel that carries blood towards the heart.

villi

vill-ee

Small finger-like parts of the small intestine. They increase the surface area so that digested food is absorbed more quickly. Singular = villus.

 

© Pearson Education Limited 2002 - copyright acknowledged