Past Mock and Exam Questions (Vitamin A)

Question 1

Forms of vitamin A

2 @ 1M each

Answer 1

Retinol

Beta-carotene

Question 2

Functions of vitamin A

3/5

Answer 2

Manufactures rhodopsin in the retina

Helps maintain healthy skin and mucous membranes

Healthy skin and hair

Aids growth and development

Beta-carotene acts as a powerful antioxidant

Question 3

Properties of vitamin A (retinol)

3/5

Answer 3

A yellow, fat-soluble alcohol

Insoluble in water

Soluble in organic solvents e.g. acetone

Heat stable, but affected by prolonged high temperatures

Destroyed by oxygen

Question 4

Properties of vitamin A (beta carotene)

3/6

Answer 4

A yellow or orange fat-soluble oil

Insoluble in water

Soluble in fat solvents, e.g. alcohol

Heat stable, but affected by prolonged high temperatures

Unaffected by oxygen

Powerful antioxidant

Question 5

Effects of deficiency of vitamin A

3/5

Answer 5

Night blindness

Follicular hyperkeratosis

Xeropthalmia

Stunted or delayed growth in children

Damage to cells/cancer

Question 6

Explain the term hypervitaminosis in relation to vitamin A

Answer 6

When a diet with an excessive intake of vitamin A (or D) which accumulate in the liver to toxic levels

Miscarriage
Birth defects
Bone pain
Enlarged liver

Question 7

What is the RDA for vitamin A for adults/adolescents?

Answer 7

600-700 micrograms

Question 8

Give a detailed account of the deficiency diseases associated with vitamin A
(3/4)

Answer 8

Xerophthalmia occurs on the surface of the eye due to a lack of mucous
This causes eyes to dry out and become infected with bacteria and can eventually lead to blindness

Follicular hyperkeratosis - This is a condition that results in rough, dry skin and inflamed hair follicles

Night Blindness - struggle to see in dim light due to a lack of rhodopsin

Damage to cells by free radicals increases the risk of some cancers, coronary heart diseases and strokes

Question 9

Describe in detail some of the functions of vitamin A

2

Answer 9

Vitamin A is required to manufacture the pigment rhodopsin found in the retina which helps the eye adapt to dim light

Vitamin A helps maintain healthy skin and the mucous membranes of the body such as the eyes, nose and throat which prevents infection

Beta-carotene acts as a powerful antioxidant that can counteract the damaging effects of free radicals