Biology Paper 2, WASSCE (PC), 2020

Question 2

 

  1. In the table below, name five classes of food provided for human consumption, one importance of each class in the diet and one example of each class.

     

    Food class

      One importance

    One example

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     


                                                                                                                                                    [15 marks]

     (b) Explain briefly how insulin regulates the amount of glucose in the blood.      [5 marks]

Observation

 

Candidates lost marks to their inability to spell the food classes and examples of food classes properly.

A few candidates were able to explain how insulin regulates the amount of glucose in blood

.

The expected answers are:

 

(a)  Food classes provided by plants and examples

 

Food class

  One importance

One example

Carbohydrate

Source of energy/starting point
for the synthesis of proteins and
fat

Starch/corn/cassava/maize/yam/rice/millet
/sorghum.

Roughage

For digestion/bowel
movement/adds
bulk to materials of the large
intestine for easy defaecation

Cereals/citrus/vegetables/fruits

Proteins

For growth and
development/repairs/for
hormones and enzymes
production

Beans/peas/groundnut/soya beans

Fats and
Oil/Lipids

Source of energy/energy
production/body insulation/
protection of organs/formation
of cell membrane/food
reserve/buoyancy

Groundnuts/soya beans/palm fruit/shea
butter/melon

Vitamins

For health/immunity/growth
development/general upkeep of
the body

Citrus fruits/vegetables/carrots/red
palm oil/ yeast

Mineral salts

For general metabolism/growth
/bones/teeth/haemoglobin
/formation of blood

Vegetables/fruits/tiger nuts/plantain/banana

                       

15 x 1[15 marks]


Note: Spellings of the food class must be correct to score.


(b)   Regulation of blood glucose by insulin

 

  • when the level of glucose in the blood rises;
  • insulin is secreted;
  • from the pancreas/islets of Langerhans;
  • insulin stimulates liver/fat/muscles to metabolise glucose;
  • to glycogen;
  • promotes build-up of fats and proteins;
  • inhibits their use as energy;
  • leading to lowering of the level of glucose in the blood.