Page 222 - SUBSEC October 2017_Neat

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02207020/CAPE/SPEC/KMS 2017
BIOLOGY
UNIT 1 – PAPER 02
KEY AND MARK SCHEME

Question 3 Specific Objectives: 3.3, 2.1, 2.2, 2.4, 2.5, 2.9, 2.10

(a) (i) Carbohydrate – glycogen 1 mark [1]

(ii) The oxygen debt is the deficit in oxygen required to oxidize the
accumulated lactic acid to pyruvate. 1 mark [1]

(iii) Procedure for calculating VO2max

1. Determine the weight, in kilograms of the athlete.
2. Exercise the athlete to maximum exertion.
3. Over a 60-second period, measure the oxygen consumption in
cm (or any acceptable answer to achieve the O2 consumption
3
in 1 minute).
4. Divide the oxygen consumption in one minute by the kilograms
to find the O2 used per kilogram.
5. That gives the volume of O2 in cm per kilogram per
3
-1
-1
minute .

5 marks [5]

(iv) Calculating VO2max

[(100-80)/80] *100 = 25%

Correct answer, even without working, 1 mark [1]

(b) (i) Plasma cells

1. Formed from B-cells (by differentiation).
2. Secrete/synthesize antibodies (against specific antigens).
3. Each type of plasma cell produces a single type of antibody.
4. The antibody agglutinates/traps inactivates the antigen.
5. They are “effector” cells – carry out the “end reaction” of
the immune response.
6. They increase in number rapidly during an infection, and
decrease after the antigen is controlled.

Phagocytes

1. Are amoeboid cells produced in the bone marrow and they
circulate in the blood.
2. They move rapidly to the site of an infection.
3. They can squeeze through capillary walls and directly invade
the infection site.
4. The engulf antigens (large proteins/bacteria etc. < 250 nm).
5. They digest and kill the pathogens in a cellular vesicle.
6. They remove alien/foreign molecules which may cause harm to
that organ, e.g. lung, liver.

Any 2 comparisons = 4 marks [4]