8.1 :Gas exchange in Unicellular organisms

Question 1

what are the 4 essential features of a respiratory surface

Answer 1

For the rapid diffusion of gasses a resp[iratory surface mus

1. Have a large surface area to volume ratio
2. Be thin the so that the diffusion pathways are short
3. Be permeable so that the gasses diffuse easier
4. Have a mechanism to produce a steep diffusion gradient accross the respiratory surface, by bringing oxygen or removing carbon dioxide rapidly

Question 2

what do the features of a single celled (unicellular) organism allow it to do?

Answer 2

single celled organisms are able to…

• absorb enough oxygen across the cell membrane to meet their needs for respiration.
• remove carbon dioxide fast enough to prevent building up a high concentration making the cytoplasm too acid for enzymes to function.

Question 3

What are the features of a unicellular organism

Answer 3

A single cell organism such as an Amoeba is very small (100 micrometres) and…

• Has a large surface area to volume ratio.
• is thin to allow diffusion into the cell rapidly.
• and also to ensure diffusion distances inside the cell is short.

Question 4

where does the diffusion of gasses occur

Answer 4

On a respiratory surface

eg.

Alveoli inside the lungs

Trachea of an insect

Spongy mesophil of a plant