2021

Question 1

State one other method of natural cloning in plants.

Answer 1

suckers / stolons / tubers / rhizomes / bulbs 

Question 2

Name the type of plant tissue from which natural clones are produced.

Answer 2

meristem

Question 3

Outline how it is possible to produce many clones from a single original parent plant.
Tissue culture greatly increases the number of cloned plants that can be produced from a
single parent plant.

Answer 3

many / AW, explants taken from , original / parent , plant

calluses subdivided 
(meristems from) plantlets can be subdivided 

Question 4

Describe how DNA can be used to provide evidence to support the theory of evolution by
natural selection. (3)

Answer 4

(DNA) found in all organisms 
some / AW , sequences highly conserved 

comparison (of DNA between species) 

similar (base) sequence indicates recent common
ancestor  o

Question 5

Suggest and explain why a low pH might cause the red pigment to leak out of the
beetroot cells.

Answer 5

(low pH) denatures / changes tertiary structure of ,
(membrane) proteins 
therefore membrane permeability (to pigment) is
increased

Question 6

Outline the process of primary succession + onwards

Answer 6

Stages

Pioneer community
* begins with bare rock
* arrival as seeds or spores
* pioneer species have certain adaptations,
e.g. nitrogen-fixation

Intermediate community
* herb species, including grasses
* followed by shrubs and trees

Climax community
* dominance by a few tree species
* little change over time

General principles
* seral stages
* community and decomposition changes
composition of soil
* increased organic, nitrate or water content

Question 7

why something would be a deflected succession

Answer 7

• climax community is prevented from
  developing
  As a result…
• plagioclimax community

Question 8

DNA profiling can be used in cases of paternity and forensics.
State one other use of DNA profiling

Answer 8

idea of assessing disease risk 
classification / species identification 

Question 9

DNA codes for proteins within the cell. Some regions of DNA are described as non-coding.
(i) Explain why some regions of DNA can be described as ‘non-coding’.

Answer 9

editing of primary , mRNA / transcript 

not present in mature mRNA 

not translated 

regulatory , sequences / genes 

Question 10

Non-coding regions of DNA show more variation than coding regions. This makes
non-coding regions useful in DNA profiling.
Suggest why non-coding regions of DNA show more variation.

Answer 10

doesn’t affect survival