CELL PHYSIOLOGY (MOVEMENT)

Question 1

How can substances move across membranes?

Answer 1

DIfussion, osmosis, facilitated diffusion, active transport, endocytosis, exocytosis.

Question 2

Explain what diffusion is?

Answer 2

The movement of molecules to a region of high concentration to an area of lower concentration.

Question 3

Why is diffusion only suitable for non polar molecules?

Answer 3

Polar molecules cant cross cause the phosphoipid tails are hydrophobic and the polar molecules are inoluable in lipid tails.

Question 4

What are the factors affecting the rate of diffusion?

Answer 4

Concentration graidient - greater graidient - faster
size - small particles diffuse faster
temperatrue - faster at high tempo - more kinetic energy
thickness - thin - shorter diffusion distance - faster
surface area - large - faster

Question 5

What is ficks law?

Answer 5

area of diffusion surface x difference in concentration
Rate of diffusion =———————————————————————
thickness of surface over which diffusion take
place

Question 6

Explain what facilitated diffusion?

Answer 6

When the diffusion process is supported by proteins, two types of protein involved in facilitated diffusion (carrier proteins and channel proteins).

Question 7

Explain what carrier proteins are?

Answer 7

take in diffusing molecule, change the shape, release on other side.

Question 8

Explain what carrier proteins are?

Answer 8

take in diffusing molecule, change the shape, release on other side. E

Question 9

Explain what channel proteins are?

Answer 9

formed by proteins with a central pore enabling charged particles to pass through, some channels are gated meaning that they can open and close at any given time.

Question 10

Explain what active transport is?

Answer 10

from low to high (against the concentration gradient, energy is required (ATP), involves protein carrier molecules, substance to be transported will bind to the carrier protein, which changes shape and will release substance once on the other side,

Question 11

Explain what osmosis is?

Answer 11

It is the net movement of water from a high water concentration to a lower water concentration across a selectively permeable membrane.

Question 12

Explain what hypertonic, hypotonic and isotonic means?

Answer 12

1. stronger solution
2. weaker solution
3. two solutions are equal concentration

Question 13

What does water potential mean?

Answer 13

It means the solutions tendency to take in water by osmosis from pure water across a selectively permeable membrane.

Question 14

What is water potential measured in?

Answer 14

Kilppascals

Question 15

What are the two factors that the potential of a cell is dependent on?

Answer 15

solute and pressure potential

Question 16

Explain solute potential?

Answer 16

Adding solute will lower the water potential, more solute the more negative the water potential, amount that solute lowers water potential is called solute potential (negative value)

Question 17

Explain the pressure potential?

Answer 17

The cell wall contributes to the pressure potential, greater pressure inside a cell the greater tendency for water to leave it. (positive value)

Question 18

What is the equation for water potential?

Answer 18

water potential = pressure potential + solute potential.