Observation

 

This question was also a popular question. Many candidates could define vitamins, although some definitions were not detailed as required. Some candidates could not give functions and deficiencies and sources of the expected vitamins on the table provided. The candidates that lost marks lost to incorrect spelling of the expected answer e.g scurry for scurvy, riket for rickets and some just wrote blindness instead of night blindness. Some candidates wrote vitamin E in place of vitamin K.

 

The importance of the given mineral elements to plants was poorly stated by many students. Some even gave the importance in animals instead of in plants; some candidates wrote that iron is important for the formation of the red blood cells and calcium for the development of strong teeth and bones.

 

 

The expected answers are:

(a) (a) Vitamins
Vitamins are organic/food substances/biocatalysts; needed in small quantities in the body; for healthy growth/development.                                                                 Any 2 x 1 [2 marks]

 

(b) Functions, deficiencies and food sources of vitamins

Vitamin	One function	One deficiency	One source
C	Resistance to diseases; for healthy gum and teeth; hastens/aids wound healing; healthy growth/protein metabolism.	Scurvy; loosening of teeth; stunted growth; sore gums; delayed healing of wounds; internal bleeding/haemorrhage.
	Regulate calcium and phosphorus Absorption from the intestine; building and maintaining bones and teeth.	Rickets; poor bone development; poor teeth development; dental caries	Liver; fish oil; eggs; Milk; butter; margarine; manufactured in the skin by sunlight/ultraviolet radiation; seed fat e.g. cocoa.
B	For proper growth; carbohydrate metabolism; healthy skin; normal functioning of heart and nervous system; cell respiration.		Yeast; milk; groundnut; beans; rice; kidney; egg white; wheat; palm wine; whole grain; lean meat; chicken; green vegetables; potato.
A		Night blindness/eye defect; retarded growth; reduced resistance; dry and scaly skin; xerophthalmia; nerve degeneration; drying of moist membrane of nasal and bronchial tubes.	Liver; red-palm oil; kidney; tomatoes; egg yolk; carrot; green vegetables; cod-liver oil; butter; margarine/cheese; peas; milk; broccoli.
K	For normal clotting of blood; normal liver function; production of prothrombin.		Green vegetables; egg yolk; liver; tomatoes; unpolished cereal/whole grains.

 

(c)  Importance of the following mineral elements to plants
(i) Iron
Formation of chlorophyll                                                                         
(ii) Nitrogen
Formation of protein/amino acids/nitrogenous bases; for normal/healthy growth;
chlorophyll formation; proper root growth.                                  
(iii) Calcium   

Cell wall formation; healthy growth; neutralization of some organic acids; activation of enzymes; helps in storage of proteins and carbohydrate in seeds and tubers.