Past Paper Questions Flashcards
Describe how you would decide the number of quadrants to use in order to collect representative data
Enough to do statistical test
Need to make sure work can be carried out in available time
Explain why the rate of co2 production was higher when the apple slices were in nitrogen than when they were in the air
Respiring anaerobically
So produce less ATP
ATP production affects co2 production
In the light-dependent reaction of photosynthesis, light energy generates ATP. Describe how
Light energy excited electrons in chlorophyll Electrons pass down ETC Electrons reduce carriers ETC in thylakoids Energy released ATP phosphorylation
Explain how and why the efficiency of energy transfer is different at different stages in the transfer in an ecosystem
Efficiency lower in older animals and herbivores
Carnivores use more of their food than herbivores
Explain how the intensive rearing of domesticated livestock increases net productivity
Slaughtered when still young
So more energy transferred to biomass
Describe how microorganisms make carbon in starch available to plants
Release enzymes
Starch to smaller molecules
Respiration produces co2
Explain why plants cannot use photosynthesis as their only source of ATP
Wouldn’t produce enough as only produces a little
Doesn’t produce ATP in the dark
What does a small surface area to volume allow
The animal to retain heat
What term is used to describe conditions which stay the same bell curve on the graph
Stabilising
Describe how microorganisms make carbon in starch available
Excrete enzymes onto it
Starch to glucose
Respiration from digestion
Respiration produces co2
If nitrogen gas is the substrate for an enzyme. What is the product?
Ammonia
What does the Hardy-Weinberg principle predict?
Proportion of ALLELES
genetic change over time
Providing no mutations/migrations etc
Explain the change in soil nitrate concentration shown in the graph
(Increases steadily)
Increase in dead organisms leading to increase in nitrification
The ratio of dry biomass in animals to the dry biomass in seaweeds is always less than one. Explain why
Loss of energy between tropic levels
Levels as result of respiration
Co2 concentration in air over 24 hours changes. Explain why
Plants respire in dark
Dark = no photosynthesis
Respiration occurs
Describe how carbon in co2 becomes carbon in triose phosphate during the light independent reaction
Co2 combines with ribulose
Produces 2 GP
Reduced to TP using NADP
Energy from ATP
Describe how microorganisms make carbon in dead worms available to cells in a leaf
Microorganisms are SAPROPHYTES Excrete enzymes Absorbs products of digestion Co2 released when they respire Co2 taken into leaves through stroma
Explain meant by the term population
Number of organisms of a species in an area at a given time
Explain what is meant by recessive allele
Only shown in phenotype when homozygous
Measuring aerobic respiration in an experiment with a woodlouse. Explain why liquid moved to the left
Woodlouse takes up oxygen
Co2 given out is absorbed by the solution
Pressure decreases
Experiment with woodlouse aerobic respiration.
What measurements should student take
Mass of woodlouse
Diameter of cross-sectional area
Position of liquid before and after certain time
In animal experiment explain why type of food they’re given needs to be controlled
Different amount of protein etc may affect absorption
In animal experiment explain why temperature needs to be controlled
Heat lost to maintain body temperature
Describe and explain how succession occurs
Pioneer species Change conditions Enables other species to colonise Change in biodiversity Stability increases so less hostile environment Climax community
Advantages and disadvantages of biological control
Good as specific to one pest
Bad as doesn’t completely get rid of pest
Give ways in which the properties of ATP make it a suitable source of energy
Releases energy in small amounts
Soluble
One quick hydrolysis step to release energy
Explain why it’s necessary for humans to synthesise a large amount of ATP
Can’t be stored
Only releases small amount of energy at one time
Immediate source of energy
Give advantages of using natural fertiliser over artificial fertiliser
Less leaching as slow release of nutrients
Contains wider range of elements
Explain why scientists chose sample at random
Avoid bias
Allows statistical test
Describe how co2 converted to organic substances during photosynthesis
Light independent reaction
Co2 combines with RUBP produce GP GP reduced to TP Using reduced NADP And energy from ATP
