More Past Paper Questions

Question 1

Energy from the sun may ultimately end up in dead plant matter. Describe how

Answer 1

Photosynthesis

Carbon-containing molecules

Question 2

What is meant by an abiotic factor

Answer 2

Physical/chemical non-living factor

Question 3

Explain how to population of trees in the forest evolved adaptations to the environment

Answer 3

Variation from mutation

Better adapted to survive

Reproductive success

Allele frequencies change

Question 4

Use evidence from the diagram to explain why the allele is recessive

Answer 4

Heterozygous carriers

Question 5

Explain how oxygen in the roots enables the root to take up nitrogen-containing substances

Answer 5

Active transport

Which requires ATP

Question 6

Explain why scientists used the same breed of pig in the investigation

Answer 6

Same breed so similar alleles

So controls variables

Question 7

Explain why ATP is useful in many biological processes

Answer 7

Immediate energy source

Able to reform/be made again

Lowers activation energy

Released in simple step

Releases little amounts of energy

Question 8

Describe how ATP is made in the mitochondria.

Answer 8

Substrate level phosphorylation 
Krebs cycle reduces NAD
Electrons released from reduced NAD
Electrons pass down ETC
Energy released
ADP + Pi
ATP synthase

Question 9

Explain why it is important for plants to produce ATP in respiration as well as photosynthesis

Answer 9

Plants use more ATP than is produced in photosynthesis

ATP used for transport and synthesis of substances

Cannot photosynthesis in the dark

ATP can’t be stored

Question 10

Suggest why the energy transfer from producers to consumers in this food web is higher than 10%

Answer 10

Eat most of the producer

Less heat/energy loss

Question 11

The species that are present change during succession. Explain why

Answer 11

Changes in environment so less hostile so other species can survive

Question 12

Use the graph to evaluate this conclusion

Answer 12

Other factors

Correlation not causation

Overlap ranges??

Question 13

What substrate does co2 combine with in a chloroplast

Answer 13

RUBP

Question 14

What are the advantages of biofuel being developed by government scientists rather than companies

Answer 14

No bias

Non-profit

Question 15

Why is petroleum used as a comparison when evaluating the co2 production of biofuels

Answer 15

It’s Commonly used

Provides standard reference for comparison

Question 16

Explain how farming practices increases the productivity of agricultural crops

Answer 16

Greenhouse use to enhance temperature etc

Ploughing soil to improve drainage

Covers and netting for protection from birds

Fertilisers
Pesticides for removing competition and pests that damage crop

Question 17

Describe how the action of microorganisms in the soil produces a source of nitrates for crop plants

Answer 17

Protein into ammonia by saprobionts

Ammonium into nitrite

Nitrite into nitrate
By nitrifying bacteria

Nitrogen to ammonia
By nitrogen-fixing bacteria

Question 18

Why are flies useful for studying genetic crosses

Answer 18

Breed fast so obtain results quicker

Large number means can do statistical tests

Question 19

Why are the observed ratios of number kids which alleles are not same as expected

Answer 19

Fertilisation is random

Fusion of games are random

Due to chance

Question 20

Explain why males likely to display a recessive allele carried on that X chromosome than females are

Answer 20

Makes only have one ALLELE

Females need 2 recessive alleles

Question 21

Where in the cell is the enzyme rubisco found

Answer 21

Stroma

Question 22

When does a yeast cell produce ethanol

Answer 22

By anaerobic respiration

Question 23

What happens during light-dependent reaction

Answer 23

Light energy hits chlorophyll

Energy lost when electrons along ETC

Energy used to join ADP + Pi to make ATP