4.1- cell transport mechanisms

Question 1

what is passive transport

Answer 1

-transport that takes place as a result of conc, pressure or electrochemical gradients and involves no energy

Question 2

active transport definition

Answer 2

-the movement of substances into and out of the cell using ATP produced in respiration

Question 3

diffusion definition

Answer 3

-the movement of the particles in a liquid or gas down a conc gradient from an area where they have a high conc to an area where they have a low conc

Question 4

facilitated diffusion definition

Answer 4

-diffusion that takes place through a carrier protein or protein channels

Question 5

osmosis definition

Answer 5

-specialised form of diffusion that involves the movement of solvent molecules down a conc gradient, through a partially permeable membrane

Question 6

AT mechanisms- endocytosis

Answer 6

-the movement of large molecules into cells through vesicle formation

Question 7

AT mechanisms- exocytosis

Answer 7

-movement of large molecules out of cells through vesicle formation

Question 8

what happens in facilitated diffusion?

Answer 8

-molecules with a strong charge or large molecules cannot cross cell membranes by simple diffusion
-these molecules are carried across the membrane in protein carriers with a matching shape
-it changes shape again to pass the molecules into the cell
-returns to original shape and process repeats
e.g. glucose
-high rate of diffusion

Question 9

water potential equation

Answer 9

water potential of a cell=
usually neg
turgor pressure+osmotic potential
usually pos usually neg

Question 10

what is turgor pressure

Answer 10

• the pressure generated as the swelling protoplasm pushes against the cell wall in plants