B2.2.1 - Exchange And Transport

Question 1

What is the surface area to volume ratio?

Answer 1

The surface area per unit volume of an object

Question 2

Why is surface area to volume ratio important?

Answer 2

It can help with diffusion

Question 3

If an organism is large, will the surface area volume ratio be higher or lower?

Answer 3

Lower

Question 4

If an organism is small, will the surface area volume ratio be higher or lower?

Answer 4

Higher

Question 5

Why can most multicellular organisms not use simple diffusion to survive?

Answer 5

It can not occur fast enough to meet the cells’ demands

Question 6

What do lungs have to help with gas exchange?

Answer 6

Alveoli

Question 7

Why are alveoli important to lungs?

Answer 7

It maximises the rate of diffusion into the bloodstream as it increases the surface area

Question 8

What are exchange surfaces?

Answer 8

A process where an organism exchanges something in need of something else

Question 9

What do intestines contain to help with diffusion?

Answer 9

Villi

Question 10

What does villi do to help the intestines?

Answer 10

It increases the surface area of the intestines

Question 11

Why is it good for the intestines to have a high surface area?

Answer 11

It increases the rate of diffusion of digested food molecules

Question 12

What do you call the villi which are on the villi that are very small?

Answer 12

Microvilli

Question 13

What tubes carry water and mineral ions around in a plant?

Answer 13

What tubes carry water and mineral ions around in a plant?

Question 14

What tubes can transport sugars and amino acids in plants?

Answer 14

Phloem tubes

Question 15

How are alveoli adapted for gas exchange?

Answer 15

Spherical shape gives relatively large surface area
Very thin walls mean shorter distance for diffusion
Ventilation moves air in and out and helps maintain a steep diffusion gradient
Good blood supply maintains concentration gradient for diffusion by removing oxygen and bringing lots of carbon dioxide

Question 16

How have villi adapted to digestive diffusion?

Answer 16

Villi are specialized for absorption in the small intestine as they have a thin wall, one cell thick, which enables a shorter diffusion path. They have a large surface area so there will be more efficient absorption of fatty acids and glycerol into the blood stream.