12drevision-ansbio

8/12/2019 12drevision-ansbio

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2/5

(c) %& Protein binds to / blocks / competes with substrate for! active site;

2& Prevents substrate from binding / prevents formation of

en=*me:substrate comple$ / e";

& Protein binds to point other than the active site of the en=*me /

reference to allosteric;

& Changes shape of active site; [8]

3. (a) # 'att* acid / h*drophobic region / tail! / phospholipid tail

0 Phosphate / gl*cerol / h*drophilic region / head! / phospholipid head

C (Channel / transmembrane / intrinsic) protein

1 7l*coprotein 2

[Half mark each, rounded down]

(b) Facilitated diffusion

-hrough channel / carrier! protein;

1own a concentration gradient / e";

Active transport

sing carrier protein;

8nerg* from #-P;

#gainst concentration gradient;

Exocytosis / endocytosis


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(ii) %& Membrane selectivel* permeable at lower temperatures;

2& -emperature increase above A BC / higher temperatures!

/ membrane breaks down / e";

& 5ncrease of kinetic energ* of pigment

molecules / phospholipids in membrane / e"!;

& Proteins are denatured;

+& Membrane becomes freel* / more! permeable to

(pigment molecules) with increasing temperature;

>& .eference to diffusion of pigment molecules out of the

cells / reaches e"uilibrium at high temperatures; [12]

4. (a) %& .eference to thin wall;

2& Single cell la*er / reference to s"uamous epithelium;

& 1ecreases diffusion distance;

& .eference to surfactants prevent alveolar collapse / cells

sticking together!;

+& .eference to network / e"! of capillaries;

>& .eference to maintenance of diffusion gradient;

(b) (i) %& #lveolar air has had o$*gen removed;

2& 8$pired air is mi$ture of (inspired) air / air in tubes!and alveolar air; 2

(ii) %& #ir (in alveoli) ventilated / replenished fre"uentl*! / e";

2& 5dea of blood flowing through the capillaries;

& .eference to o$*gen / o$*genated blood! being carried awa* /

allow converse for carbon dio$ide; 2

Barking Abbey School 3


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(c) %& Smokers babies have lower birth weight / fetus has low growth rate!;

2& 0ab* ma* have poorer lung / e"! function;

& .eference to poor brain development / function!;

& .educed o$*gen suppl* to fetus as carbon mono$ide (in smoke)

replaces o$*gen;

+& Smoking interferes with mothers uptake of vitamin 0 / C / folic acid!;

>& 5ncreased risk of placental complications e&g& placental abruption / e";

?& 5ncreased risk of still birth / premature birth / miscarriage / e"!;

@& .eference to nicotine interfering with fetal development;

D& .eference to bab* having nicotine addiction;

(d) %& 5ncreased death rate / e"! in older people / e";

2& 5ncreased death rate / e"! in middle:aged people / A:>A *ear olds!;

& .eference to cancer / emph*sema / bronchitis / circulator* disorders / e"!;

& 1ecreased birth rate / fewer children;

+& 1ecreased fertilit* / failed pregnanc* / e"! / childhood disease; 2[12]

5. (a) W E coronar* arteries

X E aorta

Y E (left) pulmonar* arter*

Z E pulmonar* vein

correct E 2 marks

2 or correct E % mark

A or % correct E A marks 2

(b) #ward one mark for each of the following points in

conte$t to a ma$imum of four&

%& ventricle (muscle) contracts;

2& higher pressure in ventricles relative to atria;

& (pressure) closes atrioventricular valve;

& higher pressure in ventricles relative to the aorta /

pulmonar* arter* / arteries!;

+& (pressure) opens the semilunar valve;

>& blood forced into the aorta / pulmonar* arter* /

arteries!; Ma$

Barking Abbey School 4


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(c) #ward one mark for each of the following points in conte$t to

a ma$imum of three&

%& place#aphnia on cavit* slide / e"! with caffeine;

2& (focus on heart) using microscope;

& ref& to range of caffeine concentrations;

& ref& to repeats;

+& ref& to water as control / =ero caffeine concentration!; Ma$

#ward one mark for each of the following points in conte$t to

a ma$imum of three&

%& control temperature;

2& reference to similar organisms used;

& accurate measurement of 1

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