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Flashcards in Past Paper Questions Deck (30)
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1
Q

Describe how you would decide the number of quadrants to use in order to collect representative data

A

Enough to do statistical test

Need to make sure work can be carried out in available time

2
Q

Explain why the rate of co2 production was higher when the apple slices were in nitrogen than when they were in the air

A

Respiring anaerobically
So produce less ATP

ATP production affects co2 production

3
Q

In the light-dependent reaction of photosynthesis, light energy generates ATP. Describe how

A
Light energy excited electrons in chlorophyll
Electrons pass down ETC
Electrons reduce carriers
ETC in thylakoids
Energy released 
ATP phosphorylation
4
Q

Explain how and why the efficiency of energy transfer is different at different stages in the transfer in an ecosystem

A

Efficiency lower in older animals and herbivores

Carnivores use more of their food than herbivores

5
Q

Explain how the intensive rearing of domesticated livestock increases net productivity

A

Slaughtered when still young

So more energy transferred to biomass

6
Q

Describe how microorganisms make carbon in starch available to plants

A

Release enzymes
Starch to smaller molecules
Respiration produces co2

7
Q

Explain why plants cannot use photosynthesis as their only source of ATP

A

Wouldn’t produce enough as only produces a little

Doesn’t produce ATP in the dark

8
Q

What does a small surface area to volume allow

A

The animal to retain heat

9
Q

What term is used to describe conditions which stay the same bell curve on the graph

A

Stabilising

10
Q

Describe how microorganisms make carbon in starch available

A

Excrete enzymes onto it
Starch to glucose
Respiration from digestion
Respiration produces co2

11
Q

If nitrogen gas is the substrate for an enzyme. What is the product?

A

Ammonia

12
Q

What does the Hardy-Weinberg principle predict?

A

Proportion of ALLELES
genetic change over time
Providing no mutations/migrations etc

13
Q

Explain the change in soil nitrate concentration shown in the graph
(Increases steadily)

A

Increase in dead organisms leading to increase in nitrification

14
Q

The ratio of dry biomass in animals to the dry biomass in seaweeds is always less than one. Explain why

A

Loss of energy between tropic levels

Levels as result of respiration

15
Q

Co2 concentration in air over 24 hours changes. Explain why

A

Plants respire in dark

Dark = no photosynthesis
Respiration occurs

16
Q

Describe how carbon in co2 becomes carbon in triose phosphate during the light independent reaction

A

Co2 combines with ribulose
Produces 2 GP
Reduced to TP using NADP
Energy from ATP

17
Q

Describe how microorganisms make carbon in dead worms available to cells in a leaf

A
Microorganisms are SAPROPHYTES
Excrete enzymes
Absorbs products of digestion
Co2 released when they respire
Co2 taken into leaves through stroma
18
Q

Explain meant by the term population

A

Number of organisms of a species in an area at a given time

19
Q

Explain what is meant by recessive allele

A

Only shown in phenotype when homozygous

20
Q

Measuring aerobic respiration in an experiment with a woodlouse. Explain why liquid moved to the left

A

Woodlouse takes up oxygen
Co2 given out is absorbed by the solution
Pressure decreases

21
Q

Experiment with woodlouse aerobic respiration.

What measurements should student take

A

Mass of woodlouse
Diameter of cross-sectional area
Position of liquid before and after certain time

22
Q

In animal experiment explain why type of food they’re given needs to be controlled

A

Different amount of protein etc may affect absorption

23
Q

In animal experiment explain why temperature needs to be controlled

A

Heat lost to maintain body temperature

24
Q

Describe and explain how succession occurs

A
Pioneer species
Change conditions
Enables other species to colonise 
Change in biodiversity
Stability increases so less hostile environment 
Climax community
25
Q

Advantages and disadvantages of biological control

A

Good as specific to one pest

Bad as doesn’t completely get rid of pest

26
Q

Give ways in which the properties of ATP make it a suitable source of energy

A

Releases energy in small amounts

Soluble

One quick hydrolysis step to release energy

27
Q

Explain why it’s necessary for humans to synthesise a large amount of ATP

A

Can’t be stored

Only releases small amount of energy at one time

Immediate source of energy

28
Q

Give advantages of using natural fertiliser over artificial fertiliser

A

Less leaching as slow release of nutrients

Contains wider range of elements

29
Q

Explain why scientists chose sample at random

A

Avoid bias

Allows statistical test

30
Q

Describe how co2 converted to organic substances during photosynthesis

A

Light independent reaction

Co2 combines with RUBP
produce GP
GP reduced to TP
Using reduced NADP
And energy from ATP