Cell transport mechanisms

Question 1

What is the model of the cell membrane

Answer 1

The fluid mosaic model

Question 2

Diffusion

Answer 2

The movement of particles down a concentration gradient

Question 3

Facilitated diffusion

Answer 3

Diffusion that takes place through carrier proteins or protein channels

Question 4

Osmosis

Answer 4

The movement of water down a concentration gradient through a partially permeable membrane

Question 5

Endocytosis

Answer 5

The movement of large molecules into the cells through vesicle formation

Question 6

Exocytosis

Answer 6

The movement of large molecules out of cells through vesicle formation

Question 7

Active transport

Answer 7

The movement of substances across the membrane of cells directly using ATP

Question 8

Isotonic solution

Answer 8

The osmotic concentration of the solutes in the solution is the same as that in cells

Question 9

Hypotonic solution

Answer 9

The osmotic concentration of solutes in the solution is lower than that in the cytoplasm of the cells

Question 10

Hypertonic solution

Answer 10

The osmotic concentration of solutes in the solution is higher than that in the cytoplasm of the cells

Question 11

What is pressure potential

Answer 11

The inward pressure of the cell wall on the cytoplasm

Question 12

What is incipient plasmolysis

Answer 12

When the cell membrane begins to pull away from the cell wall as the protoplasm shrinks

Question 13

What is water potential

Answer 13

A measure of the potential of water to move out of a solution by osmosis

Question 14

What is turgor pressure

Answer 14

A measure of the inward pressure exerted by the plant cell wall on the protoplasm of the cell as the cell contents expand and press outwards, a force which opposes the entry of water by osmosis

Question 15

What is osmotic potential

Answer 15

A measure of the potential of a solution to cause water to move into the cell across a partially permeable membrane as a result of dissolved solutes

Question 16

Calculation for water potential

Answer 16

Water potential = turgor pressure + osmotic potential

Question 17

Evidence that active transport requires ATP

Answer 17

Active transport only takes place in living, respiring cells
Rate of active transport depends on temperature and oxygen concentration, affecting respiration rate and therefore ATP production
Cells that carry out active transport usually have lots of mitochondria (site of ATP production)
Poisons that prevent respiration or ATPase also stop active transport