Cambridge International A Level Biology Revision Guide

Cambridge International A Level Biology
6 Distinguish between:
a cyclic and non-cyclic photophosphorylation [2]
b photophosphorylation and oxidative phosphorylation [2]
c the roles of NAD and NADP in a plant. [2]
[Total: 6]
7 a Draw a simple flow diagram of the Calvin cycle to show the relative positions in the cycle of the
following molecules:
CO 2
(1C)
GP/PGA (3C)
triose phosphate (3C)
RuBP (5C). [4]
b Show the point in the cycle at which the enzyme rubisco is active. [1]
[Total: 5]
8 a Explain what is meant by a limiting factor. [1]
b List four factors that may be rate-limiting in photosynthesis. [4]
c At low light intensities, increasing the temperature has little effect on the rate of photosynthesis.
At high light intensities, increasing the temperature increases the rate of photosynthesis.
Explain these observations. [5]
[Total: 10]
298
9 a Copy and complete the table to show the differences between mesophyll and bundle sheath cells in
C4 plants. Insert a tick (✓) when an item is present in the cell and a cross (✗) when it is not. [7]
Item Mesophyll cell Bundle sheath cell
PEP carboxylase
rubisco
RuBP
enzymes of Calvin cycle
high concentration of oxygen
light dependent reactions
contact with air spaces
b Explain what is meant by photorespiration. [2]
[Total: 9]
10 a Distinguish between an absorption spectrum and an action spectrum. [4]
b Pondweed was exposed to each of three different wavelengths of light for the same length of time.
For each wavelength, the number of bubbles produced from the cut ends of the pondweed were counted and
are shown in the table.
Wavelength of light / nm
Mean number of bubbles
produced in unit time
450 22
550 3
650 18
Explain these results. [4]
[Total: 8]