B3.1 - Exchange of materials

Question 1

Name two factors that affect the rate of diffusion

Answer 1

Temperature

Concentration gradient

Question 2

Name two examples of diffusion in the human body

Answer 2

Synapse

Oxygen diffusing into blood

Question 3

How is osmosis different to diffusion

Answer 3

Osmosis only happens with water particles

Question 4

What is osmosis?

Answer 4

Diffusion of water molecules from an area of high concentration to an area of low concentration across a partially permeable membrane.

Question 5

When does osmosis stop?

Answer 5

When both sides of the partially permeable membrane have equal amounts of water particles

Question 6

What is a solute?

Answer 6

Something that is dissolved in water

Question 7

Give two examples of solutes

Answer 7

Sugar

Salt

Question 8

What will happen when a cell is placed in a solution of lower concentration?

Answer 8

Solution is more dilute than that of the cell so it will absorb more water, swells and could possibly burst.

Question 9

What is it called when a cell absorbs more water and swells?

Answer 9

Iysis

Question 10

What will happen when a cell is placed in a solution of same concentration?

Answer 10

There’s no net movement so the cell will remain the same

Question 11

What will happen when a cell is placed in a more concentrated solution?

Answer 11

Will lose water because there is less water in the solution. It loses water by osmosis and the cell becomes crinkled/crenated

Question 12

What happens when you exercise

Answer 12

You respire more, using up glucose
Sweat more, losing electrolytes (mineral ions) and water
Cells will become dehydrated (water leaves by osmosis)

Question 13

What’s in a sports drink and why

Answer 13

Glucose to replenish glucose that is used in respiration
Electrolytes to replace ions lost when sweating - this keeps cells working well
Mainly water for hydration

Question 14

What is a hypotonic drink

Answer 14

Concentration of dissolved substances is lower than in the body. This means it is good for hydration

Question 15

What is an isotonic drink

Answer 15

Concentration of dissolved substances is similar to the levels of dissolved substances in the body. Good for hydration and fuel replenishment

Question 16

What is a hypertonic drink

Answer 16

Concentration of dissolved substances is higher than in the body. Replaces glucose needed for respiration

Question 17

What is the job of the lungs?

Answer 17

To transfer oxygen to the blood and remove waste CO2 from it.

Question 18

How do the lungs transfer oxygen and Carbon dioxide

Answer 18

They contain millions of little air sacs where gas exchange takes place

Question 19

What are the air sacs in the lungs called

Answer 19

Alveoli

Question 20

How are the alveoli specialised to maximise the diffusion of oxygen

Answer 20

Large surface area
Very thin walls
Good blood supply

Moist lining for dissolving gases

Question 21

Where are the villi

Answer 21

Inside the small intestine

Question 22

How do the villi work

Answer 22

They increase the surface area so digested food can be absorbed into the blood much quicker

Question 23

How are the villi adapted

Answer 23

A single layer of surface cells

Good blood supply assists quick absorption

Question 24

What is the definition of diffusion?

Answer 24

Diffusion is the movement of particles from an area of high concentration to an area of low concentration