1 What sources of protein-rich foods are available to a vegetarian who:
a will eat animal products but not meat itself
b will eat only plants and their products?

egg and dairy product.

QUORN


 2 Why must all diets contain some protein?

protein are use for growth and repair.


 3 Could you survive on a diet that contained no carbohydrate?
Justify your answer.

Yes because protein also contain energy.


4 In what sense can the fats in your diet be said to contribute to ‘keeping you warm’?

We have fat store under our skin this help to keep the heat from escaping.


5 How do proteins differ from fats (lipids) in:
a their chemical composition (Chapter 4)
b their energy value
c their role in the body?

a)fat have fatty acid and glycerol protein have carbon,nitrogen,hydrogen,and oxygen
b)protein have more energy value hthan fat.
c)protein are use for growth and repair fat are use to store energy.


6 Construct a ? owchart for the digestion and use of proteins,
similar to the one for carbohydrates in Figure 7.6.

 7 Which tissues of the body need:
a iron
b glucose
c calcium
d protein?

a)haemoglobin
b)
c)bone
d)


 8 Some examples of the food that would give a balanced diet are shown in Figure 7.29.
 Consider the picture and say what class of food or item of diet is mainly present.
For example, the meat is mainly protein but will also contain some iron.


Bread is mainly carbohydrate.VEG contain vitamin and fibre.Milk contain calcium.


9 What is the value of leafy vegetables, such as cabbage and lettuce, in the diet?


10 Why is a diet consisting mainly of one type of food,
e.g. rice or potatoes, likely to be unsatisfactory even if it is sufficient to meet
our energy needs?

11 A zoologist is trying to fi nd out whether rabbits need vitamin C in their diet.
Assuming that a suffi ciently large number of rabbits is used and adequate
controls are applied, the best design of experiment would be to give the rabbits:
a an artifi cial diet of pure protein, carbohydrate, fats, minerals and vitamins but lacking vitamin C
b an artifi cial diet as above but with extra vitamin C
c a natural diet of grass, carrots, etc. but with added vitamin C
d natural food but of one kind only, e.g. exclusively grass or exclusively carrots?
Justify your choice and say why you excluded the other alternatives.

A, because the zoologist want to find out whether the rabbit need vitamin c or not
so we need to put vitamin c out of the diet to see what happen to the rabbit.


12 Name three functions of the alimentary canal shown in Figure 7.11.


To breakdown food,to digest food,and to absorb food.


13 Into what parts of the alimentary canal do the following pour their digestive juices?
a the pancreas
b the salivary glands

The pancreas.


14 Starting from the inside, name the layers of tissue that make up the alimentary canal.


lining epithelium with digestive glands,circular muscle fibres,longitudinal muscle fibres.


15 a Why is it necessary for our food to be digested?
b Why do plants not need a digestive system?
(See ‘Photosynthesis’ in Chapter 6.)

a)if the food is not digested it will be too large for our body to absorb it.
b)because plant make their own food.


16 In which parts of the alimentary canal are the following digested?
a starch
b protein

a)mouth
b)stomach,duodenum,pancreas.


17 Study the characteristics of enzymes in Chapter 5.
In what ways does pepsin show the characteristics of an enzyme?

The pepsin break down protein.