active transport

Question 1

define active transport

Answer 1

movement against a concentration gradient from low to high

use carrier protein and ATP

Question 2

how does the sodium potassium pump work

Answer 2

actively transport sodium ions out of axon and actively transports potassium ions into axon

used in neurones
allows nerve impulses to be initiated

Question 3

outline the steps of active transport

Answer 3

ion to be transported binds to receptors on the carrier protein
on the inside of the cell, ATP binds to the carrier protein and is hydrolysed into ADP and phosphate
bindings of the phosphate molecule to the carrier protein causes the protein to change shape - opening to the inside of the cell
the ion is released to the inside of the cell
the phosphate molecule is released from the carrier protein and recombines with ADP to form ATP
the carrier protein returns to its original shape

Question 4

what is bulk transport

Answer 4

a form of active transport

large molecules and whole cells are too large to move through channels or carrier proteins

Question 5

two types of bulk trasnport

Answer 5

endocytosis = into cells
exocytosis = out of cells

Question 6

two types of endocytosis

Answer 6

pinocytosis - liquids
phagocytosis - solids

Question 7

outline the process of endocytosis

Answer 7

1. cell surface membrane invaginates when it comes into contact with the material to be transported
2. membrane enfolds the material into the cytoplasm to transfer the material for further processing within the cell [vesicle containing bacteria moved towards lysosomes where the bacteria are digested by enzymes]