Cellular transport

Question 1

what are the two types of transport?

Answer 1

• active

- passive

Question 2

what are the two types of passive transport?

Answer 2

• diffusion - simple/facilitated

- osmosis

Question 3

what is simple diffusion?

Answer 3

net movements of particles from a high to low concentration across a partially permeable membrane
- until evenly distributed

Question 4

what is facilitated diffusion?

Answer 4

diffusion for charged ions and polar molecules using carrier/channel proteins
(no ATP - uses kinetic energy (inbuilt motion) of molecules

Question 5

what factors affect diffusion rate?

Answer 5

• surface area
• charge of molecules
• gradient
• diffusion distance
• temperature
• size of molecule

Question 6

what is fick’s law?

Answer 6

          diffusion distance

Question 7

what is osmosis?

Answer 7

net movement of water molecules from a high to low potential across a partially permeable membrane

Question 8

what is active transport?

Answer 8

net movement of molecules from low to high concentrations across a partially permeable membrane using ATP and carrier proteins

Question 9

how do protein pumps work?

Answer 9

• carrier proteins bind to molecule to be transported
• bind to receptor site
• ATP binds to protein
• splits into ADP and phosphate molecule by hydrolysis
• protein can then change shape and opens on other side
• releases molecule and reverts to original shape
• ADP recombines with phosphate molecule during respiration

Question 10

how does sodium-potassium pump work?

Answer 10

as sodium is actively taken out, the potassium is actively taken in

(essential for nerve impulse)

Question 11

what is endocytosis?

Answer 11

process by which cells ingest external fluid or molecules

• phagocytosis: large particles/cell
• pinocytosis: solutes/fluids

Question 12

what is exocytosis?

Answer 12

process by which substances are released by being transported in vesicles and fusing with cell membrane

Question 13

what type of transport is co-transport?

Answer 13

active transport

Question 14

how does co-transport of glucose with sodium ions work in the mammalian ileum?

Answer 14

• sodium actively transported out of cell by sodium-potassium pump using carrier protein
• high conc of Na ions outside cell so diffuse inside cell through another carrier protein
• they couple with glucose and amino acids which are carried into cell
• pass into blood by facilitated diffusion through another carrier protein