Active Transport + Water Potential

Question 1

Active Transport?

Answer 1

movement of molecules or ions into or out of a cell from a region of low concentration to a region of higher concentration.
Requires energy and carrier proteins.
energy is needed as particles are being moved up a concentration gradient

Question 2

how do carrier proteins act as a pump?

Answer 2

• molecule or ions to be transported bind to receptors in the channel of the carrier protein.
• inside of the cell ATP binds to the carrier protein and is hydrolysed into ADP and phosphate.
• binding of phosphate molecule to carrier protein opens up the inside of the cell.
• molecule or ion released to the inside of the cell.
• phosphate molecule is released from carrier protein recombines with ADP to form ATP
• carrier protein returns to original shape

Question 3

exocytosis?

Answer 3

reverse of endocytosis
vesicles usually formed by the golgi apperatus, move towards and fuse with the cell surface membrane. contents of the vesicle are released outside of the cell

Question 4

what is osmosis?

Answer 4

diffusion of water across a partially permeable Membrane.

Question 5

if water potential is higher outside what happens?normal cell?, plant?

Answer 5

water enters cell, causing expansion

in plant cells? swells and becomes turgid

Question 6

higher water potential inside the cell? in plant also?

Answer 6

water leaves the cell - shrinks

plasmolysis, contents shrink’s

Question 7

bulk transport?

Answer 7

form of active transport.

too large to move through channel or carrier proteins so are moved by either endo or exocytosis

Question 8

endocytosis? types and process?

Answer 8

phagocytosis for solids.pinocytosis for liquids.
cell surface membrane bends inwards when Incontact with material.
membrane enfolds until the membrane fuses forming a vesicle.
vesicle pinches off and moves into the cytoplasm.