2011 Jan Unit 4

Question 1

Give two ways in which the properties of ATP make it a suitable source of energy in
biological processes.

Answer 1

Soluble
Simple reaction
The energy released in small amounts

Question 2

Explain why it is necessary for humans to synthesise such a large amount of ATP

Answer 2

ATP is unstable
ATP cant’ be stored
ATP only releases small amounts of energy

Question 3

GP of plants was highest in July. Highest temp

Answer 3

High temperature allows enzymes to work faster
A lot of light so light not limiting;
More photosynthesis;

Question 4

GP

Answer 4

= NP+R(respiration)

Question 5

The net productivity of the plants in the field was higher in August than in July. Use the
equation in part (b)(i) and your knowledge of photosynthesis and respiration to suggest
why

Answer 5

Respiration is less
Light-dependent reaction/photosynthesis less affected by
temperature increase
Lower energy loss

Question 6

How extra nutrients was used in summer

Answer 6

Stored as fat

Used for growth

Question 7

More energy is lost in March than in August

Answer 7

More heat losss in march
Need to maintain constant temp
By metabolising/respiration

Question 8

Suggest two advantages of processing waste in anaerobic digesters rather than in
open ponds.

Answer 8

Products collected
Gases not released
prevents eutrophication

Question 9

Without this cooling system, the digester would soon stop working. Explain why

Answer 9

Respiration increases temp

Enzymes would denature as a result

Question 10

The over-application of fertiliser increases the rate of leaching. Explain the
consequences of leaching of fertiliser into ponds and lakes.

Answer 10

Algae bloom
Light blocked out
Plants cant photosynthesise
Bacteria feed off dead organisms
Bacteria use up O2

Question 11

Advantage of natural fertiliser than artificial

Answer 11

Production of artificial fertiliser energy-consuming;

Less leaching / slow release (of nutrient);

Question 12

Explain what is meant by birth rate

Answer 12

Births per thousand of the population and per

year

Question 13

A breeder crossed a black male cat with a black female cat on a number of occasions.
The female cat produced 8 black kittens and 4 white kittens.
Explain the evidence that the allele for white fur is recessive

Answer 13

Parents are heterozygous

Kittens receive allele from parents

Question 14

Explain actual numbers not the same

Answer 14

Fertilisation is random

Question 15

A statistical test showed that the difference between the two frequencies of the t allele
was significant at the P = 0.05 level.

Answer 15

There is a probability of 5%/0.05;
That difference in frequencies are
due to chance;

Question 16

Explain how this type of selection led to a decrease in the frequency of the
recessive allele.

Answer 16

Directional

Dominant allele more likeley to survive

Question 17

In these forests, nitrogen in dead leaves is made available to growing plants by the
action of bacteria. Describe the role of bacteria in making the nitrogen in dead leaves
available to growing plants.

Answer 17

Saprobionts
break down proteins/nitrogen-containing
substances;
Extracellular digestion;
Ammonia/ammonium produced;
Ammonia converted to nitrite to nitrate
6. Nitrifying (bacteria)/ nitrification;
7. Oxidation;

Question 18

During photosynthesis, oil-palm trees convert carbon dioxide into organic substances.
Describe how

Answer 18

Carbon dioxide combines with RuBP;
Produces two molecules of GP;
Reduced to triose phosphate/TP;
Using reduced NADP;
Using energy from ATP;
Triose phosphate converted to other organic substances
In light independent reaction/Calvin cycle