PHS: Exploring Science 8D Unicellular Organisms

Which of these is a ‘life process’ carried out by all organisms?

• photosynthesis

• breathing

• fermentation

• respiration

Two kingdoms that contain many unicellular microorganisms are:

• prokaryotes and protoctists.

• animals and plants.

• yeast and fungi.

• viruses and bacteria.

Multicellular organisms need transport systems to carry materials to their cells because:

• diffusion is not fast enough to do this.

• diffraction is not fast enough to do this.

• dissolving is not fast enough to do this.

• dispersion is not fast enough to do this.

One feature of all prokaryotes is that they:

• have chloroplasts.

• do not have nuclei.

• do not respire.

• do not have cytoplasm.

Which of these is a food often made using yeast?

• chips

• cheese

• bread

• yoghurt

Which of these shows the correct word equation for anaerobic respiration in yeast?

• oxygen + glucose → carbon dioxide + water

• carbon dioxide + water → oxygen + glucose

• glucose → carbon dioxide + ethanol

• glucose + carbon dioxide → oxygen + water

Yeast reproduce by:

• binary fission

• binary fusion

• fermentation

• budding

The graph shows the growth of a population of yeast.

At point P the graph becomes level.

One reason for this might be that:

• the yeast cells can only grow to a certain size.

• the food for the yeast has started to run out.

• it has got dark and there is not enough light for the yeast to grow.

• the carbon dioxide for the yeast has started to run out.

Three resources needed by all bacteria for growth are:

• warmth, food and moisture.

• light, carbon dioxide and glucose.

• oxygen, nitrogen and mould.

• darkness, moisture and nitrogen

A product of fermentation of milk by bacteria is:

• ethanol

• oxygen

• glucose

• lactic acid