General questions

Question 1

What is a control and how is it set up?

Answer 1

A group that is treated in exactly the same way as the experimental group except for the factor that is being investigated
Allows scientists to make a comparison
Ensures that the data collected is valid because any differences between the results for the experimental group will be due to a single independent variable

Question 2

What is precision?

Answer 2

Smallest scale division on the measuring instrument being used
A set of …. measurements will have very little spread about the mean value

Question 3

Differences in the primary structure of haemoglobin molecules can provide evidence of phylogenetic (evolutionary) relationships between species.
Explain how

Answer 3

Mutations change base / nucleotide (sequence)
Causing change in amino acid sequence
Mutations build up over time
More mutations between distantly related species
Closely related species have recent common ancestor

Question 4

What does standard deviation (SD) show?

Answer 4

The spread of data around the mean

Question 5

What does standard deviation (SD) reduce?

Answer 5

The effect of anomalies