Biology · Oct / Nov 2023 · Paper 42 · Question 5

any two from:

single circulation / blood flows through the heart once on one circuit of the body ;

ref. to, one atrium and one ventricle / two chambers in the heart ; no septum in the heart ;

only deoxygenated blood / no separation of oxygenated and deoxygenated blood, in the heart ;

blood is under less pressure ;

any three from:

1

prevents mixing of oxygenated and deoxygenated blood ;

2

blood able to flow at high pressure (to the body) ;

3

efficient / fast, supply of, blood / glucose / oxygen / nutrients ; 4

efficient / fast, removal of, waste / carbon dioxide / urea / lactic acid ; 5

allows efficient filtration in kidneys (for excretion) ;

to allow / maintain, a high, metabolic rate / rate of respiration ; 6

7

lower pressure, in pulmonary circuit / to lungs ;

8

to prevent damage to, delicate tissue / capillaries, in lungs ; 9

allows more time for gas exchange ;

10 AVP ;

C ;

A ;

D ;

B ;

hepatic portal vein ;

any four from:

1

deamination / removal of nitrogen-containing part of amino acids ; 2

removing excess amino acids (from blood regulating concentration of amino acids (in blood)) ;

3

forming urea ;

4

urea, released / diffuses, into blood (to travel to kidney) ;

5

breakdown / respiration / oxidation, of lactic acid ;

6&7 AVP ;