U1T5 - Keywords

Question 1

Diffusion

Answer 1

The net movement of molecules/ions from a region of high concentration to a region of low concentration down a concentration gradient until equilibrium is reached. Passive process.

Question 2

Fick’s Law

Answer 2

Rate of diffusion in a given direction across the exchange surface is directly proportional to the surface area + concentration gradient + inversely proportional to the distance (length of diffusion pathway.)

Question 3

Binding site

Answer 3

Receptor site which is complementary in shape to molecule being transported.

Question 4

Channel protein

Answer 4

Protein with central pore.

Question 5

Active Transport

Answer 5

Transport of ions/molecules across membrane against a concentration gradient using energy in one direction. Involves protein carrier molecules (pumps) which have receptor sites which are complementary to binding molecule. Substance binds to protein which changes shape + releases substance on other side of membrane then reverts to its original shape.

Question 6

Cytosis

Answer 6

Substances can be transported into or out of cell without having to pass through membrane.

Question 7

Phagocytosis

Answer 7

Transport of solid material into cell (engulf bacteria)

Question 8

Pinocytosis

Answer 8

Transport of fluid into cell.

Question 9

Exocytosis

Answer 9

Movement of substances out of cell. Secretory vesicles move to + fuse with cell surface membrane. Vesicle’s contents released out of cell + gap formed is closed.

Question 10

Osmosis

Answer 10

Net movement of water molecules from region of high water conc/high water potential to low water conc/low water potential through a selectively permeable membrane.

Question 11

Hypotonic

Answer 11

Weak solution

Question 12

Hypertonic

Answer 12

Strong solution

Question 13

Isotonic

Answer 13

When 2 solutions are of equal conc + no osmosis.

Question 14

Water potential

Answer 14

A measure of the free kinetic energy of water molecules. Tendency for water molecules to enter/leave solution.

Question 15

Solute potential

Answer 15

The potential for a solution to take in water. Measure of the reduction in water potential due to presence of solute molecules.

Question 16

Pressure potential

Answer 16

Effect of pressure on a solution.

Question 17

Osmoregulation

Answer 17

The way the cell ensures osmotic concentrations of body fluids are precisely regulated. Same water potential is maintained inside + outside body dells.

Question 18

Lysis

Answer 18

When a cell bursts as water has entered the cell by osmosis.

Question 19

Haemolysis

Answer 19

The bursting of a red blood cell due to water entering it by osmosis.

Question 20

Crenation

Answer 20

When cell becomes crinkled and water has left it by osmosis.

Question 21

Contractile Vacuole

Answer 21

Tiny water pump amoeba has which pumps out excess water. Salt is pumped into it so vacuole fills with water which is then expelled. Lower water potential in cytoplasm + higher in vacuole so water moves into vacuole.

Question 22

Plasmolysis

Answer 22

Shrinkage of the cell membrane away from the cell wall of a plant cell as a result of water being lost from the cell by osmosis. Plasmodesmata stays attached. Cytoplasm + vacuole smaller.

Question 23

Incipient plasmolysis

Answer 23

The point where water potential inside and outside cell are the same, the cytoplasm is just coming away from cell wall. Pressure potential is 0.

Question 24

Protoplast

Answer 24

Everything inside the cell wall.

Question 25

Full turgor

Answer 25

The state of turgidity + rigidity of cell due to the absorption of fluid.

Question 26

Flaccid

Answer 26

Drooping/inelastic through lack of water.

Question 27

Wilted

Answer 27

To become limp through heat, loss of water, or disease; droop.

Question 28

Turgid

Answer 28

When the cell contents pushes against the cell wall and water has moved into the cell.