OCR Biology A Level Revision Quiz

Which labelled features identify these cells as eukaryotic?

• W, X and Y

• W and X only

• W only

• X only

Some secretory cells synthesise and release glycoproteins. What is the correct order of the sequence of events as they occur in the secretory cell?

1 exocytosis

2 product accumulates in secretory vesicle

3 mRNA binds to ribosomes

4 synthesis of glycoprotein

• 3, 4, 1, 2

• 3, 4, 2, 1

• 4, 3, 1, 2

• 4, 3, 2, 1

Bacterial cells divide by a process called binary fission. Which macromolecules must be synthesised for binary fission?

1 cell membrane proteins and RNA

2 DNA and peptidoglycan

3 enzymes and cellulose

• 1, 2 and 3

• 1 and 2 only

• 2 and 3 only

• 3 only

A student carried out experiments to investigate the effect of enzyme concentration on the rate of hydrolysis (break down) of protein in milk.

When the enzyme and milk were mixed, the protein was hydrolysed and the mixture changed from cloudy to clear. The student investigated five different enzyme concentrations and recorded the time taken to reach the end-point for each.

What is an appropriate control for this investigation?

• Carrying out a further experiment where the enzyme solution is replaced with water.

• Carrying out each experiment in a thermostatically regulated water-bath at 35 °C.

• Performing three repeat experiments for each of the five enzyme concentrations.

• Using the same volume of enzyme solution for each of the five experiments.

What determines the specificity of an enzyme?

1 the bonding between R groups of the polypeptide

2 the optimum pH of the enzyme

3 the peptide bonds between amino acids of the polypeptide

4 the shape of the substrate molecule

• 1, 2, 3 and 4

• 1 and 3 only

• 1 only

• 2, 3 and 4 only

The graph shows the effect of temperature on the rate at which the enzyme in a biological washing powder digests and removes fruit juice stains.

Which statements explain the shape of the graph at temperatures higher than X?

• Bonds are broken between the R groups of the amino acids in the polypeptide chains of the enzyme.

• There are more collisions between the enzyme and its substrate.

• The tertiary structure of the enzyme is altered.

• The shapes of the active site and the substrate are no longer complementary.

Which of the following mutations will have the greatest effect on the protein produced?

• insertion

• deletion

• frameshift

• missense

The diagrams represent transverse sections of three plant organs.

• A

• B

• C

• D

Which statements about water movement in plants are correct?

1 Water can pass through cellulose cell walls.

2 Water can pass through lignified cell walls.

3 Water cannot pass through suberin in cell walls.

• 1, 2 and 3

• 1 and 2 only

• 1 and 3 only

• 2 and 3 only

The contraction of the heart is coordinated through electrical impulses passing through the cardiac muscle. Which is the correct order of part of the sequence of these impulses?

A right and left atria → sinoatrial node → atrioventricular node → ventricular walls

B sinoatrial node → right and left atria → atrioventricular node → Purkyne tissue

C sinoatrial node → right and left atria → Purkyne tissue → atrioventricular node

D sinoatrial node → right and left atria → Purkyne tissue → ventricular walls

• A

• B

• C

• D