HARD questions i tend to forget

Question 1

Explain how species could have evolved (6marks)

Answer 1

Geographical isolation- leading to allopathic speciation (reproductive isolation) so no interbreeding occurs

Random mutation- because of different selection pressures (biotic/abiotic conditions)

Natural selection- selected organisms survive and reproduce so increases allele frequency.

Question 2

Describe how to carry out a mark-release-recapture method to estimate the no. of a population species (4 marks)

Answer 2

1. Capture a sample of the population, count, mark and release them.
2. Ensure that the marking method isn’t harmful or makes it visible to predators
3. Leave sufficient time for species to randomly distribute
4. Capture a second sample & count the no. of marked species.

Calculate no. of population= no. first sample x no. in second sample / number recaptured

Question 3

Explain why CO2 uptake is a measure of net productivity

Answer 3

It shows gross photosynthesis minus respiration

Question 4

Which statistical test could the scientist use to determine whether his observed resultswere
significantly different from the expected results?
Give the reason for your choice of statistical test.

Answer 4

The chi_squared test because it uses categorical data

Question 5

Mitochondrial disease (MD) often causes muscle weakness (lines 1–3). Use your
knowledge of respiration and muscle contraction to suggest explanations for this effect of MD

Answer 5

Les ATP produced by aeróbic respiration so less force generated because fewer actin and myosin interact in muscles and the fatigue is caused by lactate formed from anaerobic respiration.

Question 6

What is the role of ATP in myofibril contraction?

Answer 6

1.Provides energy to move myosin head, allows binding to actin
2. Allows power-stroke

Question 7

Describe how the results from a colorimeter can identify sugar content (1(

Answer 7

The higher absorbance the more sugar
or
the lower the transmission the less sugar content

Question 8

State how enzymes help reactions to proceed quickly at lower temperatures (1)

Answer 8

Lowering/reducing the activation energy

Question 9

What term is used to describe the method of naming organisms by their species name and genus?

Answer 9

Binomial nomenclature

Question 10

How can a gene mutation have no effect on an individual?

Answer 10

• Genetic code is degenerate
• Mutation is on an intron
• does change amino acid but not tertiary structure
• new allele is recessive so does not influenced phenotype

Question 11

How can a gene mutation have a positive effect on an individual ?

Answer 11

• may increase reproductive success Or increase survival chances

Question 12

What is stratified sampling?

Answer 12

Random simplista based on sub-groups

Question 13

Why can the reducing sugar test be classed as semi-quantitative?

Answer 13

Gives as an idea of how much reducing sugar concentration there is but not the exact value

Question 14

Define the quaternary structure of a protein

Answer 14

More than 1 polypeptide