2019

Question 1

Some attempts at gene therapy have resulted in changes to the functioning of other
genes.
Explain how inserting a new gene into a chromosome could affect the functioning of other genes in that chromosome.

Answer 1

frameshift 
altered triplet(s) 
adjacent / nearby , genes (on same chromosome)
switched , on / off 
idea that new gene could disable a functioning gene if
inserted into it

Question 2

Describe what is happening at stage A and suggest a practical procedure that could allow this to occur.

Answer 2

nucleus from , tadpole / donor cell , fuses with / enters / AW ,
(enucleated) egg 
using , needle / micropipette / electric pulse / electrofusion 

Question 3

The frog produced by the process in Fig. 19.1 is not a complete clone of the donor
tadpole.
Suggest why the cloned frog might not be considered a complete clone of the donor tadpole

Answer 3

some genes present in mitochondria from egg cell 
random / spontaneous , mutations 

Question 4

Describe and explain how an investigation could be improved in order to have more
confidence in any conclusions drawn from the results.

Answer 4

E facilitates identification of anomalies
E increases accuracy of the mean
E allows assessment of repeatability / precision
D calculate mean
E more representative of treatment
D calculate range / standard deviation
E add bars to graph
E measures variability of results
E standard deviation less affected by anomalous
results
D perform statistical test / (unpaired) Students ttest
E assess significance of difference
E because comparing 2 means

Question 5

Identify three advantages of vegetative propagation in agriculture

Answer 5

some crop plants cannot reproduce , sexually / from
seed 
young seedlings , less likely to survive / AW 
quicker than , growing from seed / sexual
reproduction 
uniform / predictable , shape / size / quality / yield 
idea of easier to harvest 
(propagation) can be done , at any season / time of
year

Question 6

Water has many properties that are essential for living organisms.
Explain how properties relating to the density of water contribute to the survival of organisms
APART FROM ice , is less dense than water / floats, and how it insulates underneath

Answer 6

ice , provides habitat for some species
(aquatic) animals / gametes / spores , can move
water is similar density to living organisms 
organisms can float

Question 7

Plants rely on osmosis for support.
Explain the importance of osmosis in plant support.

Answer 7

water enters vacuole 
pressure against cell wall 
turgor (pressure) 
turgid cells (support plant) 

Question 8

Define osmosis.

Answer 8

diffusion / net movement , of water across a , partially /
selectively , permeable membrane
NOT SEMI, AND NET NEEDED
down a , water potential / Ψ , gradient 

Question 9

Nitrogenous bases structure

Answer 9

Question 10

Nitrogenous bases structure

Answer 10