Question 7
(a)(i) complete the table of digestive secretions shown below.
Digestive secretion |
Where produced |
Major component of secretion |
One function of the component |
Saliva |
|
Salivary amylase |
|
Gastic juice |
|
water |
|
bile |
|
Bile salt |
|
Pancreatic juice |
|
Mineral salt |
|
Intestinal juice |
|
sucrase |
|
[10 marks]
(a)(ii) State two functions of fat in humans. [2 marks]
(b) State six functions of the liver. [6 marks]
(c) Name two structures of the female reproductive system. [2 marks]
Observation
-
This question was attempted by many candidates and their performance was poor. In part (a)(i) majority of the candidates could not correctly state where digestive enzymes are produced and their functions. In part (b) they did not do well in it. In part (c) many candidates correctly named structures of the female reproductive system.
The expected answers are as follows:
7. (a) (i) COMPLETED TABLE
DIGESTIVE
SCRETIONWHERE
PRODUCEDMAJOR COMPONENT
ONE FUNCTION OF EACH
COMPONENTSaliva
Salivary gland / Mouth
Salivary amylase
Digests cooked starch/converts starch to maltose
Gastric juice
Stomach / Gastric wall / Cells
Water
It aids digestion/enzymes actions
Bile
Liver
Bile salt
Emulsifies fats/absorption of vitamin K/Neutralises acidic medium
Pancreatic juice
Pancreas
Mineral salt
Help to increase alkalinity in the intestine
Intestinal juice
Small intestine
Sucrase
Splits sucrose into glucose and galactose
1 mark for each column 1x10 = 10marks
(ii) FUNCTIONS OF FATS IN HUMANS
- source of energy
- source of heat / keeps the body warm / insulator
- rounds off angular contours of the body/provide shape
- it protects delicate organs in the body
- solvent of fat soluble vitamins
(b) FUNCTIONS OF THE LIVER
- produces blood cells in early life
- secretion of bile
- storage of glycogen
- deamination/breakdown of protein with the formation of urea
- production of plasma protein (albumin and globulin)
- desaturation of fats
- production / storage of vitamins and iron
- production of heat
- destruction of various toxic substances and drugs/detoxification
- production of heparin/prothrombin/fibrinogen
- stores blood temporarily
- regulates blood sugar / converts glycogen to glucose
- destroys old red blood cells
(c) STRUCTURES OF THE FEMALE REPRODUCTIVE SYSTEM
- ovaries
- fallopian tubes/oviduct
- uterus/womb
- cervix
- vagina
- clitoris
- vulva