2. Food is needed for:
1.
2.
3.
4.
Energy and warmth
Growth
Repairing and replacing tissues
Keeping the body healthy and fight disease

3. The amount of energy needed by a
person depends upon:1)
2)
3)
4)
age
sex
temperature
job

4. A balanced diet is composed of the
right amounts of:1.
2.
3.
4.
5.
6.
7.
Water
Carbohydrates
Lipids
Proteins
Mineral salts
Vitamins
Dietary fibre or
roughage

5. The food guide pyramid
1.
2.
3.
4.
5.
6.
7.
Water
Carbohydrates
Lipids
Proteins
Mineral salts
Vitamins
Dietary fibre or roughage

6. Malnutrition
 condition that results from taking an
unbalanced diet in which certain nutrients
are:
 lacking
 in excess (too high an intake)
 or in the wrong proportions

7. Components of a balanced diet :1.
2.
3.
4.
5.
6.
7.
Water
Carbohydrates
Lipids
Proteins
Mineral salts
Vitamins
Dietary fibre or roughage

8. Uses of water in organisms:1. as part of cytoplasm (most cells contain 75%
water)
2. as a solvent in which chemical reaction occur
3. to activate enzymes
4. for photosynthesis in plants
5. for growth and support in plants
6. to transport substances round the body (blood
has a lot of water)
7. brings about cooling on evaporating

9. Animals get water from:1. Drinking
2. Eating
3. Chemical reactions e.g.
respiration
food
H2O
O2
ATP

10. Components of a balanced diet :1.
2.
3.
4.
5.
6.
7.
Water
Carbohydrates
Lipids
Proteins
Mineral salts
Vitamins
Dietary fibre or roughage

11. CARBOHYDRATES
 contain the elements:
 Carbon
 Hydrogen
 Oxygen
 have more oxygen than fats
 Glucose:
 is the simplest carbohydrate (C6 H12 O6)

12. Easy to remember elements:
Food
Carbohydrates
Lipids
Proteins
Elements
C, H, O
C, H, O
C, H, O, N [sometimes
S and P]

13. Food rich in carbohydrates

14. Uses of carbohydrates:a) provide energy (17kJ/g)
Sugar in energy drink
equivalent to six pastries.

15. Question: MAY, 2004
Give biological explanations for each
of the following statements:
The diet of athletes is usually high in
carbohydrates. (5)
Athletes need a lot of energy. Carbohydrates are
the body’s main energy source. Carbohydrates
like starch in bread are digested into glucose.
Glucose is used in respiration to release energy. If
athletes take in monosaccharides, i.e. sugars e.g.
glucose, they are provided with energy very
quickly.

16. Uses of carbohydrates:b) to store energy
e.g. starch in
potatoes or roots
c) to build cell walls in
plants
Cell wall
Storage
organs

17. Uses of carbohydrates:d) fibre is important to prevent constipation
Food sources of fibre:
whole wheat, bran, fresh or
dried fruit & vegetables.
Constipated!!

18. In what form are excess carbohydrates stored?
1) in plants: starch
2) in animals: glycogen
Name two places
in animals where
glycogen is stored.
Liver & muscles

19. Three types of carbohydrates
1. Monosaccharides
e.g. glucose, fructose
2. Disaccharides
e.g. maltose, lactose, sucrose
3. Polysaccharides
e.g. starch, glycogen, cellulose

20. Monosaccharides
Disaccharides
Polysaccharides
Sweet
&
Soluble
Not sweet
&
Insoluble

21. Name the monosaccharide which forms
starch, glycogen and cellulose. Glucose
Glycogen
Cellulose
Starch

22. How do starch, glycogen and cellulose
differ?
The way glucose units
are linked together
Glycogen
Cellulose
Starch

23. Question: MAY, 2008 (IIB)
Where in a plant would you expect to find:
i) Cellulose (1)
ii) Starch (1)
i) Cellulose – found in cell walls of plant cell
ii) Starch – found stored in roots /
storage organs

24. Why is the tired athlete choosing sugar
rather than starch?
Sugars, especially
monosaccharides can
be used for respiration
right away.
Starch needs to be
digested first.

25. Components of a balanced diet :1.
2.
3.
4.
5.
6.
7.
Water
Carbohydrates
Lipids
Proteins
Mineral salts
Vitamins
Dietary fibre or roughage

26. LIPIDS
 a name for fats and oils
 contain the elements:- C, H, O
lard

27. Food rich in lipids:Nuts
Egg yolk

28.  uses of lipid
a) provide energy (39 kJ/g)
b) store energy

29.  uses of lipid
c) insulation in mammals
d) protection of delicate
organs from bumps
Fat lines body wall of a rabbit.
Fat around kidney.

30. Question: MAY, 2008 (IIB)
Explain why one kilogram of starch crops
releases less energy when burnt, compared to
one kilogram of oil crops. (2)
Starch is a carbohydrate whilst oil is a lipid.
Carbohydrates have a lower energy content
than lipids.

31.  building blocks of a lipid molecule:
 Glycerol
 Fatty acids
A molecule of fat

32.  excess lipids are stored:1) in the ADIPOSE TISSUE under the skin
2) around organs
Fat around
heart.

33. What does this
pyramid show about
intake of lipids?
Few lipids must be
taken.

34. What happens to a person’s weight when:
Weight remains constant

35. What happens to a person’s weight when:
Obese person
Weight increases

36. What happens to a person’s weight when:
Weight decreases

37. Components of a balanced diet :1.
2.
3.
4.
5.
6.
7.
Water
Carbohydrates
Lipids
Proteins
Mineral salts
Vitamins
Dietary fibre or roughage

38. PROTEINS
 contain the elements: C, H, O, N (sometimes S
and P)
 food rich in proteins: Meat
 Fish
 Egg white
 Cheese

39.  Uses of proteins:1. for growth
2. for cell repair and replacement
3. to make enzymes
4. to make antibodies

40. What are the building blocks
of proteins called?

41.  Two amino acids are linked by a:
Peptide bond
 Polypeptide: many amino acids are linked

42.  A protein: many polypeptides joined up

43. different amino acids occur in proteins

44.  Two types of amino acids:
1. Essential [8 amino acids]
must be eaten as they
cannot be made by the
body
2. non-essential
can be made by the
body

45.  contain significant amounts of all the essential
amino acids
 Source: animals : eggs, meat, fish, cheese
 deficient in one or more essential amino acid
 Source: plants

46.  For example, corn is deficient in one
amino acid
 Individuals who eat only corn would show
symptoms of protein deficiency.
• This is true from any diet limited to a
single plant source, including:
 Rice
 Wheat
 or potatoes

47.  are an exception:

48. Soya bean protein is a
good source of protein,
for vegetarians and
vegans or for people
who cannot afford
meat. Explain.

49. Have you ever tasted:
 Soya bean milk
 Tofu
Tofu is made by coagulating soya
milk and then pressing the resulting
curds into soft white blocks.

50.  is referred to as:

51. Artificial meat is manufactured from :
 soya beans
 bacteria and fungi
Artificial meat is flavoured
and textured to taste like
chicken or ham.

53. How can protein deficiency from a vegetarian
diet be avoided?
By eating a
combination of plant
foods that complement
each other to supply all
essential amino acids.

54.  For example, beans supply the lysine that
is missing in corn, and corn provides
the methionine which is deficient
in beans.

55. Excess proteins:
 cannot be stored in the body
 are broken down in the liver by a process
called DEAMINATION
 the waste product produced is called UREA
liver

56. Components of a balanced diet :1.
2.
3.
4.
5.
6.
7.
Water
Carbohydrates
Lipids
Proteins
Mineral salts
Vitamins
Dietary fibre or roughage

57. MINERAL SALTS
 contain certain elements that help cells to
function properly

58. CALCIUM
 is needed for:a) hard bones and teeth
b) muscles to contract
c) to clot blood
 is found in:
 milk
 cheese
 fish

59. Rickets:
deformed
bones
 deficiency of
calcium

60. IRON
 is needed to build the red pigment in blood
called haemoglobin

61. IRON
 is found in:
 red meat like liver &
kidneys
 green vegetables: spinach,
broccoli

62. A lack of iron results in:
ANAEMIA
Normal amount of
red blood cells
Anaemic amount of
red blood cells

63. Question: MAY, 2004
Give biological explanations for each of the
following statements:
a) A dietician suggested to an anaemic person to
include liver in the diet. (5)
Person lacks iron. Red meat like liver is rich in
iron. Iron is needed to form haemoglobin in red
blood cells.

64. b) Nutritionists often
recommend a low
intake of fried foods. (5)
 Fats provide a lot of
energy. May lead to
obesity.
 Fried foods are rich in cholesterol that may
block arteries = higher risk for a heart attack.

65. MAGNESIUM
 forms the centre of the chlorophyll molecule
in green plants
No magnesium:
yellow leaves

66. Components of a balanced diet :1.
2.
3.
4.
5.
6.
7.
Water
Carbohydrates
Lipids
Proteins
Mineral salts
Vitamins
Dietary fibre or roughage

67. VITAMINS
 needed in small quantities for the normal
chemical activities of the body
 cannot be used as:
 a source of energy
OR
 to build cell structures

68. A disease develops if a vitamin is missing. How
can the person be cured?
By taking the missing vitamin.

69.  vitamins can be :a) Water soluble – vitamins B and C
b) Fat soluble – vitamins A, D, E, K

70. Why is it better to
steam vegetables
rather than boil them?
Water-soluble vitamins are
lost from the vegetables
when they are boiled but
not when steamed.

71. Vitamin
Food source
A
Milk, liver
C
Citrus fruit,
potatoes
Milk, liver
D
Deficiency
disease
Night
blindness
Scurvy
Rickets

72. Carrots are a rich source of
vitamin A
Vitamin A prevents
night blindness.

73. QUESTION: MAY 2010
Explain why the student used this picture when
mentioning night blindness. (2)
Night blindness is caused by a lack of Vitamin A
in the diet. 1 mark
Carrots are a good source of Vitamin A that can
help to prevent night blindness. 1 mark

74. Found in
Citrus fruit

75. Deficiency of Vitamin C:

76. Which vitamin prevents colds?

78. Vitamin D is made by the
action of sunlight on the
skin.
Normal
Deficiency of
Vitamin D:
Rickets

79. NOTE:
 Lack of calcium
 Lack of vitamin D
Reason:
Vitamin D helps the body to
absorb calcium from the
foods we eat.
The more calcium the body
can absorb, the stronger the
bones will become

80. Question: Sep, 2004
What special provisions should be made in the
diet of young children and pregnant mothers?
Explain why each provision you mention is
important. (6, 4)
Young children:
1. High protein content food – e.g. meat for
growth
2. Drink a lot of milk – supplies proteins,
calcium, Vitamin A & D.
3. Include carbohydrate-rich foods – for energy

81. Pregnant women:
1. Folic acid (a vitamin B) – in
citrus fruit, legumes: to form
the nervous system of the
embryo
2. Food rich in iron – e.g. liver, green
vegetables: to have enough blood in
placenta to nourish embryo
3. Calcium-rich food – e.g. dairy products to
supply embryo with calcium to form its
skeleton

82. Question: Sep, 2004
Give a biological explanation for each of the
following statements.
a) Daily inclusion of too much Vitamin C in the
diet is a waste. (2)
Vitamin C cannot be stored in the body as it
is water-soluble. Lost in urine.

83. Give a biological explanation for each of the
following statements.
a) Small doses of Vitamin D (5-10mg per day)
are recommended for housebound people
spending a lot of time indoors. (2)
Vitamin D cannot be made by the action of
sunlight on the skin. To have enough
Vitamin D, supplements are
needed.

84. Question: MAY, 2004
Give biological explanations for each
of the following statements:
a) School canteens are encouraged
to sell unsweetened cereals rather
than sweets. (5)
Sweets are carbohydrates that
provide energy.
Too much sweets may lead to obesity.
Obesity leads to higher risk of diseases.
Sweets increase chance for tooth decay.

85. b) Young children are
encouraged to eat dairy
products regularly. (5)
Milk is rich in:
 calcium – needed to form
strong bones and teeth.
 proteins – needed for
growth.
 Vitamins – for healthy growth; e.g. vitamin A to
prevent night blindness and vitamin D to help in
the absorption of calcium and to prevent rickets.

86. Components of a balanced diet :1.
2.
3.
4.
5.
6.
7.
Water
Carbohydrates
Lipids
Proteins
Mineral salts
Vitamins
Dietary fibre or roughage

87. DIETARY FIBRE or ROUGHAGE
 sources of fibre: vegetables
 fresh fruit
 bran cereals
 wholemeal bread

88. Cellulose : is the main source of dietary fibre
Explain why although humans cannot digest
dietary fibre, it is still important.

89. Functions of roughage:1. adds bulk to the contents of the intestine
and keeps food moving along the gut
Gut

90. Functions of roughage:2. prevents constipation as fibre retains water
so that the faeces are soft
3. prevents cancer of the colon (part of the
intestine)
faeces

92. Food
Starch
Iodine
solution
Starch
Test
+ iodine solution
Colour
change
Yellow to blue
black

93. Look at this picture.
Is starch present in potato?
Yes.

94. Food
Test
+ sodium hydroxide solution +
Protein
1-2 drops of copper sulfate
(Biuret test) solution
2. Copper
sulfate
solution
1. Sodium
hydroxide
solution
Egg white
[protein]
Colour
change
Blue to purple

95. A positive test for
protein was obtained
albumin
for………………

96. Food
Oil
Test
Colour
change
+ ethanol + shake + water + A white emulsion
shake
forms

97. Food
Test
Colour
change
Oil
rub food onto a dry piece of
filter paper
A greasy spot
forms

99. Food
Glucose
Test
+ Benedict’s solution
Fehling’s solution + heat
Colour
change
or Blue to brick red
or orange

100. Food
Glucose
Test
+ Benedict’s solution
Fehling’s solution + heat
Colour
change
or Blue to brick red
or orange

101. Food
Starch
Colour
change
Test
Yellow to blue
black
+ iodine solution
+ sodium hydroxide solution +
Protein
1-2 drops of copper sulfate
(Biuret test) solution
Blue to purple
1) + ethanol + shake + water + A white emulsion
shake
forms
Oil
1) rub food onto a dry piece of
filter paper
Glucose
+ Benedict’s solution
Fehling’s solution + heat
A greasy spot
forms
or Blue to brick red
or orange

102. When the food to be tested is a solid:
1. Crush the food with some water using a
pestle and a mortar.
2. Filter.
3. Add the reagents to the filtrate.
pestle
mortar

103. How do you find how
much energy is present
in a peanut?
 Burn a peanut
 Record rise in
temperature of a
known volume of
water.

104. Why is it better to have a larger
volume of water?
To absorb more heat.

105. Q = mc
Heat energy =
mass x specific heat capacity x temperature rise
Energy in peanut =
mass of water x 4.2 x temperature rise in C
1000
4.2 kJ
kg-1 C-1
1000: to work
mass in kg

106. Question: MAY, 2011 [IIB]
A group of biology students would like to
compare the energy stored in two types of
nuts: a peanut and an almond.
Describe an experiment to show how this is
carried out. In your report include:
i) The apparatus required; (You can present
this in the form of a diagram.) (2)

108. ii) The method; (3)
Known quantity of the nut (kept constant for
both nuts) ignited and held under test tube
with known amount of water (kept constant
for both nuts). The temperature of water
before lighting the nut and after burning will
be recorded.
iii) The measurements that need to be taken;
 Initial temperature and final temperature
 Mass of peanut/almond
 Volume of water (2)

109. iv) The factors that need to be kept constant
throughout the experiment; (2)
Same mass of nut and same quantity of
water.
v) ONE possible source of error. (1)
 Heat loss to surroundings
 Heat reaching water not evenly spread
out
 Burning of nut is not complete

110. How is the energy content of food
found out?
Burning food in a
bomb calorimeter.

111. Bomb Calorimeter
The apparatus which is used to find the energy
content of food.
Better than previous
setup:
1. No heat loss to air.
2. Even heat spread.

112. The End