3.3.1 Surface area to volume ratio Flashcards Preview

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Flashcards in 3.3.1 Surface area to volume ratio Deck (20):
1

The name given to the environment surrounding a cell

tissue fluid

2

Single celled organisms can match their metabolic demands by

simple diffusion

3

Exchange of materials in living organisms occurs at ..

exchange surfaces e.g. lungs, intestine

4

How much material that needs to be exchanged in an organism depends on

its size and its metabolic rate

5

Substances a cell exchanges with its environment include

oxygen, carbon dioxide, nutrients (glucose)

6

Exchange of materials in living organisms takes place via (4 types of transport)..

simple diffusion
facilitated diffusion
osmosis
active transport

7

As an organism gets larger what happens to its surface area to volume ratio?

its gets smaller - less efficient exchange.
Special exchange surfaces therefore required i.e. lungs

8

How do larger organisms cope with their increasing size?

They have specialised exchange surfaces - which have large surface area:volume ratio!

OR

they are flat and thin therefore no cell is too far away from the surface

9

What is ficks law?

diffusion rate is directly proportional to surface area x difference in concentration divided by length of the diffusion pahway

10

How are specialised exchange surfaces adapted?

1. Large surface area to volume ratio
2. Thin - short diffusion pathway
3. Selectively permeable
4. Extensive blood supply to maintain concentration gradient

11

single celled organisms SA: volume ratio is described as

large surface area to volume ratio

12

single celled organisms obtain their nutrients via..

simple diffusion

13

Why are insects usually small

their tracheal system relies on diffusion, for this to be efficient the diffusion path needs to be short and this is only achieved if the insects are small

14

Maths Skills:
If a cube had a side length of 1cm, what would it's SA be?

6 cm2

15

Maths Skills:
If a cube had a side length of 1cm, what would it's volume be?

1 cm3

16

Maths Skills:
What is the SA:V ratio of a cube with a side of 1cm

6:1

17

Maths Skills:
How do you calculate the volume of a sphere?

4/3 x 3.14 x r3

(3.14 = pi, r = radius)

18

Maths skills:
How do you calculate the surface area of a sphere?

4 x 3.14 x r2

(3.14 = pi, r = radius)

19

List 4 features of specialised exchange surfaces

1. Large SA - increases rate of exchange
2.Thin - short diffusion distance
3. Selectively permeable - allows selected materials to cross
4. Diffusion gradient maintained - eg by movement of medium - blood, air

20

Remember substances not only have to move into cells, they have to move into organelles too.
What would move into mitochondria and why?

Oxygen and glucose for (aerobic) respiration