Targeted

Question 1

What is an arbitrary unit?

Answer 1

A non-conventional unit.

Question 2

Advantages and disadvantages of GM toxins in crop plants.

Answer 2

• (adv) crop produces a toxin that kills insects - increased crop yield
• (dis) GM crops are expensive, not every farmer can afford them.

Question 3

What sub-cellular structures can be found in bacteria cells, but not animal cells?

Answer 3

cell wall
capsule / slime coat
small ribosome
pili / pilus
mesosome
plasmid DNA

Question 4

State 3 reasons why the fossil record is incomplete?

Answer 4

• not every decayed organism was in the right conditions to be fossilised
• the fossils may be damaged due to environmental problems (e.g earthquakes)
• some fossils are yet to be found

Question 5

How would one “validate” a discovery in the scientific field?

(3 reasons)

Answer 5

• getting other scientists to peer-review their work
• publishing the results on a scientific journal site
• participating in scientific conferences to discuss the findings with other scientists

Question 6

What is speciation?

Answer 6

• a change in characteristics that produces a new species (1 mark)
• this new species is unable to reproduce with the species of which it decended from. (1 mark)

Question 7

Why is mitochondrial DNA often used instead of nuclear DNA as evidence for evolution?

(State 3 reasons)

Answer 7

• there is a high mutation rate in mitochondrial DNA
• there is a higher abundance of mitchondrial DNA than nuclear
• Mitochondrial DNA is less susceptible to decay

Question 8

Explain why a patient may be given an artificial heart.

Answer 8

An artificial heart gives the heart a rest (1) whilst waiting for a transplant. (1)

Question 9

Name the FOUR stages in the process of speciation.

Answer 9

Isolation / populations being separated (1)
Genetic variation (1)
Natural selection (1)
Speciation (1)