survival and response exam questions Flashcards
use your knowledge of indoleacetic acid (IAA) to explain the growth curvature shown in figure 1 (3 marks)
M1: tip produces IAA
M2: IAA diffuses into the shoot
M3: more elongation of cells on one side than the other
Using the procedure in figure 2 and the calibration curve in figure 3 describe how you could compare the IAA concentration in shoot tips from two different plant species
In your answer you should refer to all the variables that should be controlled to produce valid comparison (5 marks)
M1: size of shoot
M2: number of shoot tips
M3: temperature
M4: compare degree of curvature on calibration curve to determine IAA concentration
M5: repeat several times to calculate a mean
State two conclusions about IAA that you can make from the results shown in the table above (2 marks)
M1: IAA is produced in the dark
M2: IAA moves away from light
Name the type of behaviour shown by beetles G, J, P and R and suggest one advantage to adult beetles of the type of behaviour shown. (2 marks)
M1: positive phototaxis
M2: to avoid predators
After studying these experiments, a student concluded
- there is a significant change in movement between 35°C and 37.5°C
- between 35°C and 37.5°C more beetles move away from the light
- between 35°C and 37.5°C more beetles have a slower walking speed
Suggest why these conclusions might not be valid (3 marks)
M1: no stats test so do not know if change in move,ent away from light is significant
M2: between 35°C and 36.5°C more than half of beetles are still found on the light side
M3: at higher temperatures beetles might be flying
Explain why the student removes the shoot tip from each seedling (2 marks)
M1: Tip produces IAA
M2: affects concentration of IAA
Explain why the student added glucose solution to each Petri dish (2 marks)
M1: for respiration
M2: provides energy for growth
Explain why the lids were kept on the Petri dishes (2 marks)
M1: to reduce evaporation
M2: which alters concentration of IAA solution
Describe and explain the results shown in table 1 above and suggest how the results might have differed if lengths of root had been used (3 marks)
M1: increase in IAA concentration the higher the mean change in length
M2: high IAA stimulates cell elongation
M3: in roots, elongation less inhibited
The nerve pathway shown in the diagram may be regarded as a simple reflex arc
Use the diagram to explain why (1 mark)
only three neurones in reflex arc
Suggest two advantages of simple reflexes (2 marks)
M1: rapid
M2: do not have to be learnt
State a null hypothesis the marine biologists tested in this investigation (1 mark )
the type of light has no effect on the behaviour of COTS
Suggest two factors that should be kept constant in the choice chambers so that COTS display normal behaviour (1 mark)
temperature of the water
A journalist studying table 1 suggest that either type of light could be used to cause COTS to move away from coral reefs
Evaluate the journalists suggestion (3 marks)
M1: negative photo taxis to both types of light
M2: movement away from constant light is not due to chance as p=0.02
M3: movement away from flashing light is not significant as p=0.69
give one similarity and one difference between a taxis and a tropism (2 marks)
M1: similarity - directional response to a stimulus
M2: difference - taxis organism moves and tropism a growth response
What do these results show about the responses of the roots of tomato plants to gravity and salt ? (3 marks)
M1: grow in direction of gravity
M2: grow away from salt
M3: salt has more of an effect than gravity
Explain why this root tip would grow away from salt (3 marks)
M1: more carriers in cell L
M2: so less IAA in cell L
M3: so more elongation in L
The biologists concluded that the worms behaviour s. How do these results support this conclusion? (2 marks )
M1: taxis is movement towards stimulus
M2: move towards temperature they were used to
Using the information provided, suggest an explanation for the worms behaviour on the glass surfaces in the absence of food. (3 marks)
M1: hungry so seeking food
M2: move towards temperature they were used to
M3: associate temperature with the food
In each experiment, the biologist exposed the surfaces to light that was dim and even, so he could see where the worms went
Apart from seeing where the worms went, suggest two reasons why it was importing that the light was dim and even (2 marks)
M1: Dim worms are affected by bright light
M2: even because it prevents worms showing phototaxis
In the test plot of land, identify the push stimulus and the pull stimulus (1 mark)
push - legume
pull - grass
when measuring the mean percentage damage to maize plants, 60 plants from each test plot were selected at random and examined
Describe how the maize plants could be selected at random (3 marks)
M1: make a grid of plot
M2: use random number generator
M3: to generate coordinates
The legume plants have nodules containing nitrogen fixing bacteria on their roots. Explain how nitrogen fixing bacteria could increase the growth of maize (2 marks)
M1: nitrogen fixing bacteria convert nitrogen in the air into ammonium compounds in the soil which are converted into nitrates
M2: maize used nitrates for protein production
In the test plot, bare ground was left between the maize and grass species
Suggest an explanation why (2 marks)
M1: to prevent competition between maize and the grass species Suggest
M2: for light
