Year 9 Movement

Question 1

How can substances move in and out of the cells ?

Answer 1

Diffusion

Question 2

What is diffusion ?

Answer 2

The spreading out of liquid or gas particles form a high concentration to a low concentration down the concentration gradient scale

Question 3

What are the 3 things that affect the rate of diffusion ?

Answer 3

Temperature, surface area and the concentration gradient

Question 4

How does the concentration gradient affect the rate of diffusion ?

Answer 4

The greater the difference in concentration, the quicker the rate of diffusion.

Question 5

How does the temperature affect the rate of diffusion ?

Answer 5

The higher the temperature, the more kinetic energy the particles will have, so they will move and mix more quickly.

Question 6

How does the surface area affect the rate of diffusion ?

Answer 6

The greater the surface area, the faster the rate of diffusion.

Question 7

How do you calculate the surface area to volume ratio ?

Answer 7

Surface area = length* width *6 (for a cube) Volume= (for a cube) whatever the length cubed

Question 8

How to calculate the volume ?

Answer 8

Volume = Height × width × depth

Question 9

If you have a larger surface area to volume ratio will the object be bigger or smaller ?

Answer 9

Smaller

Question 10

If you have a smaller surface area to volume ratio will the object be bigger or smaller ?

Answer 10

Larger

Question 11

How is the effectiveness of an exchange surface increased ?

Answer 11

• a large surface area,
• A thin membrane = short diffusion
• have an efficient blood supply
• (in animals, for gaseous exchange) being ventilated.

Question 12

How have the small intestine been adapted for exchanging materials ?

Answer 12

• Highly folded surface lined with specialised intestinal epithelial cells = increase SA
• Villus has a good blood supply - maintains a concentration gradient
• One layer of epithelial cells covers the surface of each villus – decreases diffusion distance

Question 13

How have the lungs been adapted for exchanging materials ?

Answer 13

• Millions of alveoli - increases SA
• The wall of an alveolus is one cell thick, with a moist lining and good blood supply - maintains a concentration gradient

Question 14

How have the gills been adapted for exchanging materials ?

Answer 14

• A gill is made from lots of smaller plates filaments, which are covered in projections (lamellae) – increases SA
• Dense capillary network = good blood supply which flows in the other direction to water passing through the gills – maintains a concentration gradient

Question 15

How have the roots been adapted for exchanging materials ?

Answer 15

• The root network is highly branched - increases SA
• The surface of the roots are covered in root hair cells, which have a specialised structure with root hair projections – increases SA

Question 16

How have the leaves been adapted for exchanging materials ?

Answer 16

-Stomata tiny openings that cover the lower side of the leaf, allows air to circulate the leaf – decreases diffusion distance for CO2 and oxygen
- The lower layer of the leaf is made from spongy mesophyll cells which allow air to circulate inside the leaf