B3 - Diffusion

B3 - Movement of Substances into & out of the cell

Diffusion

Draw your prediction of where the molecules will be after:

• 10 second

• 1 minute

Justify your drawing in few sentences.

Multiple Choice

What is diffusion?

• The movement of substances from low concentration gradient to high concentration gradient.

• The movement of substances from high concentration gradient to low concentration gradient.

• The movement of substances into the cell with energy.

Multiple Choice

Which of the following is involves in diffusion?

• large food molecules

• water molecules

• gas and solution particles

Multiple Choice

One of the importance of diffusion for human and animals is...

• carbon dioxide diffuses into the lungs

• oxygen diffuses out of the lungs

• oxygen diffuses into the plant cell

• oxygen diffuses into the lungs

Multiple Choice

Into which cell will the oxygen diffuse the fastest?

• A

• B

• C

• D

Today's success criteria

• factors affecting the rate of diffusion

• investigate the effect of surface area on the rate of diffusion

Factors affecting the rate of diffusion

• Temperature

• Distance

• Concentration gradient

• Surface area to volume ratio

Surface area to volume ratio

• As these cubes illustrate the surface area to volume ratio of a small object is larger than that of a large object of similar shape.

• Allows sufficient exchange to support the contents of the cell.

• As a cell grows, its SA/V decreases.

Conclusion

The greater the SA/V, the larger the amount of raw materials that can enter cell at one time.

Independent work (Type your answer in the padlet link shared)

• If a cell is too big, it cannot rely on diffusion to get what it needs. For example, by the time oxygen and glucose diffuses to the middle of the cell, the cell will have run out of energy.

• How do you think animals and plants, which are made up of millions of cells survive if they cannot rely on diffusion?

Exit Ticket

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