Unit 3 - Movement into and out of cells

Question 1

What is the definition of Diffusion?

Answer 1

Net movement of particles from a region of high concentration to lower concentration over time. Requiring no energy to do so.

Question 2

What is the concentration gradient?

Answer 2

difference between 2 areas

Question 3

What is equilibrium

Answer 3

When particles are evenly distributed through a space

Question 4

Factors that affect rate of diffusion

4

Answer 4

1. concentration gradient - larger = faster
2. temperature - more energy = faster
3. surface area - larger = faster
4. distance- larger = longer time

Question 5

Why is diffusion important (in animals)

3

Answer 5

1. gettign raw materials for respiration or photosynthesis
2. removing waste products
3. importing or exporting products ( eg proteins)

Question 6

What is osmosis?

Answer 6

net movement of water molecules from an area od hugh water potential to an area of low water potential through a partially permiable membrane . repuiring no energy to do so.

Question 7

Solute concentration in water potential

Answer 7

• low water concentration (potential ) high solutes
• high water concentration (potential ) low solutes

Question 8

Biological examples of water as a solvent

3

Answer 8

1. digestion - water used to dissolve solutes from your food
2. excretion - water used to dissolve solutes in your urine
3. transport - water used to dissolve solues in your blood

Question 9

What is a hypertonic solution

Answer 9

one that has a higher solute concentration than the cell

Question 10

What is a hypotonic solution?

Answer 10

one that has a lower solute concentration than the cell

Question 11

What is an isotonic solution?

Answer 11

has an equal concentration fo solutes inside and outside the cell.

Question 12

What happens to plant cells in a hypertonic solution?

Answer 12

• net movement out of the cell causing a reduction in tugor pressure and cell membrane to peel back from the cell wall
• known as plasmolysed

Question 13

Plant cells in a hypotonic solution

Answer 13

• net movement of water into the cell
• increase in tugor pressure and become turgid, cell membrane pushes agaisnt cell wall.

Question 14

What is active transport

Answer 14

movement of particles through a cell membrane from a region of lower concentration to higher concentration through a partially permeable membrane . using energy from respiration.

Question 15

What does active transport use and involve?

Answer 15

• uses atp as an energy source ( biological energy)
• involves carries proteins in the membrane

Question 16

Active transport in a root hair cell (ion)

Answer 16

• plants need ions to survive
• ions are in lower concentration inthe soil than they are un the cell, therefore for the plant to get enough ions they use active transport

Question 17

What is dialysis tubing?

Answer 17

a non-living semi-permeable membrane, similar to the membrane around our cells. It allows through small molecules eg water whilst larger molecules eg sugar cant pass through

Question 18

When is dialysis tubing needed ?

Answer 18

used by patients with kideny faliure who need dialysis to filter their blood