1.2 Membrane transport

Question 1

roughly how thick is cell membrane

Answer 1

7mn

Question 2

what is the cell membranes made for

Answer 2

phospholipid bilayer and membrane protein

Question 3

why do we have a control experiment

Answer 3

to compare the results of an experiment where no treatment is applied

Question 4

Convert 5 mm to µm.

Answer 4

5000 µm

Question 5

What does a selectively permeable membrane mean?

Answer 5

Membrane that only allows some types of substances to pass through

Question 6

Define passive transport

Answer 6

Down the concentration gradient and does not require energy.

Question 7

Name two types of passive transport in cells

Answer 7

Diffusion and osmosis

Question 8

Define diffusion

Answer 8

The movement of molecules down a concentration gradient from a higher to a lower concentration

Question 9

Define osmosis

Answer 9

The movement of water molecules from a high water concentration to a low water concentration through a selectively permeable membrane

Question 10

Name a substance that diffuses into our cells for use.

Answer 10

Oxygen, glucose

Question 11

Name a substance that diffuses out of our cells to be removed.

Answer 11

Carbon dioxide, urea

Question 12

What does ‘net movement’ mean?

Answer 12

Overall movement: the direction that most of the particles are moving in

Question 13

State three factors that affect the rate of diffusion.

Answer 13

Concentration gradient, temperature, surface area

Question 14

How does concentration difference affect the rate of diffusion?

Answer 14

Higher concentration difference/Steeper concentration gradient –> faster diffusion

Question 15

If a cell is in a solution of a lower water concentration, water will ___ (enter/leave) the cell.

Answer 15

Leave

Question 16

If a cell is in a solution of a higher water concentration, water will ___ (enter/leave) the cell.

Answer 16

Enter

Question 17

What will happen to an animal cell in a lower water concentration?

Answer 17

Water leaves cell –> shrinks

Question 18

What will happen to an animal cell in a higher water concentration?

Answer 18

Water enters cell –> burst

Question 19

Why do animal cells burst in lower water concentration solutions?

Answer 19

No cell wall

Question 20

What will happen to a plant cell in a lower water concentration?

Answer 20

Water leaves cell –> plasmolysed

Question 21

What will happen to a plant cell in a higher water concentration?

Answer 21

Water enters cell –> turgid

Question 22

What does ‘plasmolysed’ mean?

Answer 22

The cell membrane pulls away from cell wall

Question 23

How do we calculate % change in mass?

Answer 23

(final mass - initial mass)/initial mass x 100

Question 24

Define active transport

Answer 24

The movement of molecules and ions against the concentration gradient using energy and membrane proteins

Question 25

Explain the importance of active transport in plants.

Answer 25

Root hair cells carry out active transport to absorb mineral ions effectively in dilute soil

Question 26

State one adaptation cells may have if they need to carry out active transport.

Answer 26

Lots of mitochondria to release energy via aerobic respiration

Question 27

How does active transport differ from diffusion and osmosis?

Answer 27

Active transport uses energy, diffusion and osmosis do not

Question 28

State two differences between diffusion and osmosis.

Answer 28

D: Any particles, does not need a membrane; O: Water specific, needs partially permeable membrane