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Biology-Cell Biology > Diffusion > Flashcards

Flashcards in Diffusion Deck (10):
1

Substances may move into and out of cells via osmosis.

True or False?

False

Substances may move into and out of cells via DIFFUSION

2

Diffusion is the spreading of the __________ of any substance in solution, or particles of a ______, resulting in the net movement from an area of _________ concentration to an area of __________ concentration

Particles
Gas
Higher
Lower

3

What are some of the substances transported in and out of cells by diffusion in gas exchange?

Oxygen
Carbon dioxide

4

DIFFUSION

Of the waste product ______ from cells into the blood ________ for excretion in the ________

Urea
Plasma
Kidney

5

What are the factors that affect the rate of diffusion?

-Difference in concentrations (concentration gradient)
-Temperature
-Surface area of the membrane

6

A ______-celled organism has a relatively large _______ area to _______ ratio. This allows sufficient transport of __________ into and out of the cell to meet the needs of the __________

Single
Surface
Volume
Molecules
Organism

7

In multicellular organisms, what does the smaller surface area to volume ratio mean and what does it allow?

Surfaces and organ systems are specialised for exchanging materials. This is to allow sufficient molecules to be transported into and out of cells for the organisms needs

8

The effectiveness of an exchange surface is increased by...?

-Having a large surface area
-A thin membrane, to provide a short diffusion path
-Having sufficient blood supply (animals)
-Being ventilated (gaseous exchange)(in animals)

9

How do you calculate the surface area to volume ratio?

SA
----
Vol

10

Why does diffusion occur quickly in the small intestine?

It is covered in villi which increases the surface area. The villi have a high concentration gradient and the blood supply has a lower concentration gradient.