Biology · May / June 2025 · Paper 42 · Question 2

component of

letter from

function

blood

Fig. 2.1

red blood cell

F

transport / carry / AW, oxygen lymphocyte

G

production of antibodies transport / carries / contains / holds / AW, (blood) cells / ions / nutrients / hormones / proteins plasma

H

/ antibodies

/ carbon dioxide / urea / waste / heat

A solvent OR maintain, blood pressure / pH / osmotic balance phagocyte

E

phagocytosis

(description of blood) platelet

J

clotting / prevent blood loss / release fibrin ;;;;;

HIV / human immunodeficiency (virus) / AVP ;

any two from:

(contaminated) surfaces / objects ;

food ;

water ;

faeces / sewage ;

soil ;

air ;

(named) animals / vector ;

any three from:

1

ref. to specificity OR antibodies have complementary (shape) to, antigen / pathogen ;

2

fit / bind, to (specific) antigens ;

3

mark / clump / immobilise / neutralise / inactivate, pathogens / toxins ;

4

(for) destruction of pathogens / phagocytosis / described ; 5

AVP ;

any three from:

active immunity:

1

(gained) as a result of infection / vaccination ;

2

antibodies are produced (by the body / lymphocytes / memory cells) ;

3

produces memory cells / ref to secondary immune response ; 4

long-term / permanent ;

5

slower response ;