Page 40 - Biology Form Two

Biology for Secondary Schools

maintenance of body shape, sugars. They dissolve in water to
digestion, lubrication, and cooling form sweet solutions. Disaccharides
the body. are formed by combining two
12. A balanced diet constitutes all the monosaccharide molecules through
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nutrients needed by the body in condensation. Some disaccharides
the right proportion. (like maltose and lactose) are
13. Maintaining a healthy lifestyle is reducing sugars while others are non-
important for normal functioning reducing sugars (like sucrose). On
of the body. Proper diet helps a the other hand, polysaccharides are
person to remain healthy. formed by condensation of several
14. Nutritional requirements for monosaccharides to form a long
different groups of people vary chain. They are all non-reducing
depending on age, sex, work, and sugars. They do not dissolve in
general body condition of a person. water.
For example, pregnant women
and breastfeeding mothers need 18. Benedict’s solution is used to
a diet that has adequate nutrients test for reducing sugars. When
necessary to maintain their bodies testing for non-reducing sugars,
and help their foetuses and babies hydrochloric acid is used to
grow properly. hydrolyse disaccharides to
15. There are different types of nutritional monosaccharides. Then Benedict’s
disorders and deficiencies in solution is used to test for any
human beings. These are generally monosaccharides produced. Iodine
called malnutrition. is used to test for starch.

16. (a) Examples of nutritional 19. Proteins are made of long chains of
disorders are obesity, anorexia amino acids. Amino acids contain
nervosa, and bulimia nervosa. both acidic carboxyl groups and
(b) Examples of nutritional basic amino groups, so they can
deficiency diseases are react with both bases and acids.
marasmus, kwashiorkor, and
rickets. 20. Lipids are made up of glycerol and
fatty acids. Lipids are insoluble
17. There are three types of carbohydrates, in water but dissolve in organic
which are monosaccharides, solvents. The grease spot test,
disaccharides and polysaccharides. Sudan III test, and emulsion test
Monosaccharides are reducing are used to test for lipids.

Student’s Book - Form Two
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