Page 217 - SUBSEC October 2017_Neat

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

Question 1 Specific Objectives: 1.4, 3.1, 3.3, 3.4, 4.3, 4.5

(i) Plot same shape, but lower plateau [1 mark]. [1]

(ii) Plotting graph

 Title
 Plot 4 of 5 points correctly to get the mark
 Axes correctly labelled with units
 Scale/Plot takes up at least half of the grid
4 marks

(iii) Differences between movement of energy and nutrients

1. Energy flows through and is converted from one form to another
vs nutrients recycled.
2. Energy lost while flowing through ecosystem.
3. Unidirectional flow of energy (multidirectional for nutrient
cycling)
4. Finite nature of nutrients vs. continuous supply of energy.
5. Nutrient cycles between abiotic and biotic components/ energy
flow through organisms.

2 marks each for any full comparison = 4 marks [4]
(1 mark for partial)

(b) (i) V - Fixing nitrogen into the plants (Rhizobium bacteria)
Z – Denitrifying bacteria converting nitrate to nitrogen gas
1 mark each [2]

(ii) Parasitism vs mutualism

1. Named examples for each relationship (2)
2. Parasitism: indicate how host is harmed and how parasite
benefits (1)
3. Mutualism: indicate how both organisms gain from the
interaction (1)
4 marks [4]