Paper 2 Practice questions

Question 1

This question is about genetic engineering
We want to a put a growth hormone into a plasmid that contains 2 genes resistant to tetracycline and ampicillin
why is only the tetracycline cut out?

Answer 1

The enzyme used to cut the plasmid has a specific active site
the tetracycline have different bases
so tetracycline is complementary to the enzymes active site

Question 1

Possible causes of extinction

Answer 1

New predators
competition for mates
competition for food
asteroid collision
ice ages
volcanic eruptions

Question 2

suggest one advantage of growing tomato plants that are genetically identical

Answer 2

They all have the same named desirable characterisitcs
grow at the same rate
ready to harvest at the same time

Question 3

The farmer wants to produce a new variety of chicken that is good for both meat and egg production
describe how selective breeding would achieve this

Answer 3

Breed the best of A and B together

select the offspring with the highest egg count and fastest growing

breed the offspring together
repeat over many generations

Question 4

Many early life forms were soft bodied explain why this makes it difficult for us to know what they were like

Answer 4

Lack of fossils
because of decaying and destruction by geological activity

Question 5

Explain how the production of thyroxine increases body temperature

Answer 5

Thyroxine increases the metabolic rate 7
more respiration occurs
which relases energy

Question 5

Explain how a decrease in the concentration of ADH leads to a lower concentration of dissolved substances in the urine

Answer 5

Tubules become less permeable to water
so less water is reabsorbed
more water in urine causing an increased rate of production of urine
so more water in urine causing a lower concentration of dissolved substances

Question 6

discuss the advantages and disadvantages of cloning compared to sexual reproduction

Answer 6

Advantages
Large number of identical offspring produced
guranteed desired characterisitcs
economically profitable
Disadvantages
Higher susceptibility to disease decreases the gene pool
Helps a species increases its numbers

Question 7

explain why a students brain temperature dropped after drinking cold water?

Answer 7

Blood becomes cool
cooled blood cools brain

Question 8

A change in brain temperature led to a change in the temperature of the surface layer of the skin
why?

Answer 8

Impulses from the brain to the skin vessels supplying skin surface constrict so less heat loss by skin

Question 9

why is protien not filterd by the kidneys?

Answer 9

As it is too large a molecule for the kidney tubules

Question 10

Describe how a kidney dialysis machine works

Answer 10

restores concentration of dissolved substances to a normal level
waste passes into dialysis fluid

Question 11

describe how the amount of water in the body is controlled by the kidneys

Answer 11

filter blood
reabsorp water
in sufficent qualities to keep body water constant