L1-Surface area to volume ratio

B

Answer the following question?

Smaller animals have a larger surface area to volume ratio than bigger animals.

As a result, smaller animals experience faster …1? loss. To compensate for this, smaller animals must carry out …2? at an increased rate.

1.heat. 2.respiration

Explanation:

Smaller animals lose heat more quickly as a result of their bodies’ larger surface area to volume ratio.

Respiration is a process that releases heat, helping the body to keep warm.

So, to maintain their body temperature, smaller animals carry out more respiration.

Answer the following question?

State 3 reasons why organisms need to exchange things with their environment?

1) Cells need to take in oxygen (for aerobic respiration) and nutrients

2) They also need to excrete waste products like carbon dioxide and urea.

3) Most organisms need to stay at roughly the same temperature, so heat needs to be exchanged too.

Example:

Answer the questions in the image:

The larger the surfacs area the more …1? across the membranes since there is more arra for particles to diffuse.

2. Answer the question in the image:

1.diffusion

Small organisms VS large organisms:

A simple unicllar organisms ( one cell organisms) can rely on …1? to move substances into and out of the cell

its surface area is …2? compared to its volume, so nutrients and other substances (oxygen, water and carbon dioxide) can pass …3? through the membrane and around it's body.

Multicellular organisms such as plant or animal cells have a …4? surface area compared to its volume

Due to this, multicellular organisms need a specialized exchange surface (lungs) and transport systems (circulatory system)

Info:Organisms need to supply every cell with glucose and oxygen, and also need to remove waste products.

In single-celled organisms, these substances can diffuse directly into (or out of the cell across the cell-surface membrane. 5.Explain why the diffusion rate is quick?

In multicellular animals, diffusion across the outer membrane is too slow, for two reasons. 6.Explain the 2 reasons?

1.diffusion. 2.large. 3.quickly. 4.small

5.Substances travel small distances

6.•Some cells are deep within the body - there's a big distance between them and the outside environment

•Larger animals have a low surface area to volume ratio - it's difficult to exchange enough substances to supply a large volume of animal through a relatively small outer surface.