Search our library of Biology questions

Top answers

Biology

All levels

How is blood glucose levels controlled by the body (homeostasis) ?

Controlling high blood glucoseBlood glucose levels are important to control because glucose is our key source of energy in respiration. When blood glucose levels are too high, this...

Answered by Nazeya B. • Biology tutor

2132 Views

Using your knowledge of osmosis, describe what happens to a red blood cell when they are placed in a beaker of distilled water.

The distilled water is a hypotonic solution and so has a higher water potential than that of the red blood cell. Due to the difference in water potentials, water will move from the beaker into the red blo...

Answered by Karishma R. • Biology tutor

11324 Views

Putting bee honey on a cut kills bacteria. Honey contains a high concentration of sugar. Use your knowledge of water potential to suggest how putting honey on a cut kills bacteria.

Sugar is a solute, so honey contains a high concentration of solutes. This increases the solute potential, and decreases the water potential of honey, which is therefore lower than the water potential in ...

Answered by Nighat K. • Biology tutor

2555 Views

Give three features of an efficient exchange surface. Provide an example for each feature.

An efficient exchange surface should have a high surface area as this increases the rate at which diffusion can occur across it. For instance, roots have many root hair cells. These root hair cells have t...

Answered by Elliot H. • Biology tutor

10327 Views

How is a nerve impulse transmitted across a synapse?

Synapses are a gap or a junction between two neurones. When a nerve impulse is travelling along the axon of the first neurone and the impulse reaches the axon terminal (the end of the axon), a chemical ca...

Answered by Smita K. • Biology tutor

3268 Views