Key concepts in Biology - exam question practice

Which of these parts is not found in a bacterial cell?

• Nucleus

• Cell membrane

• Ribosomes

If the concentration of water inside the cell is lower then outside the cell, what will the net movement of water molecules be?

• Into the cell

• Out of the cell

Diffusion is where particles spread out from...

• ...an area of lower concentration to an area of higher concentration.

• 
  ...an area of higher concentration to an area of lower concentration.

Chloroplasts...

• ...strengthen a plant cell.

• ...store all the genetic material of a cell.

• ...absorb light energy to make glucose.

When using a light microscope to view a slide, which lens should be selected to start with?

• Lowest-powered objective lens

• Highest-powered objective lens

At 37 degrees C, it took amylase 80 seconds to breakdown all the starch in a solution. What was the rate of reaction?

• 20s-1

• 0.08s-1

• 12.5s-1

Why is the shape of an enzyme important for it's function?

• So that it can squeeze through small gaps.

• So that it can enter the cells of the body.

• So that it fits the substance involved in the reaction it is catalysing.

Proteases catalyse the breakdown of ...

• ...lipids to glycerol and fatty acids.

• ... proteins into amino acids.

• ... carbohydrates into simple sugars.

Explain what is meant by an enzyme being 'denatured'?

Answer explanation

The shape of the enzymes active site has changed so the substrate won't fit anymore.

Explain why the structure of the egg cell membrane changes after fertilisation.

Answer explanation

To prevent further sperm cells from entering the egg (1) which makes sure the offspring has the correct amount of DNA (1).