Diffusion and Active Transport

Question 1

Define diffusion ?

Answer 1

The net movement of molecules or ions from a region of high concentration to lower, until an equilibrium is achieved

Question 2

Is diffusion passive and why?

Answer 2

passive process that depends on molecules/ions kinetic energy

all particles are constantly in motion
motion is random
particle area constantly bouncing off one another

Question 3

State fixs law

Answer 3

rate of diffusion= surface area x concentration gradient/ diffusion difference

Question 4

What increases the rate of diffusion ?

Answer 4

Larger concentration gradient
Larger surface area
Higher temperature
Thinner length of diffusion pathway

Question 5

Which molecules can diffuse through the cell surface membrane

Answer 5

small, nonpolar lipid-soluble

Question 6

What is facilitated diffusion?

Answer 6

the movement is made easier by transmembrane channels and carriers that occur at specific points

Question 7

Describe how carrier proteins work

Answer 7

span across plasma membrane

molecule binds with proteins causing it to change shape and release the molecule inside the shell

Question 8

Define Active transport

Answer 8

movement of molecule or ions in/out of a cell from an area of lower concentration to a region of higher concentration using ATP and carrier proteins

Question 9

When are where is ATP produced?

Answer 9

by the mitochondria during respiration

Question 10

How is ATP used in Active transport?

Answer 10

used to directly move molecules

or move molecules using a concentration gradient set up by Active transport (cotransport)

Question 11

How does Active Transport differ from passive forms of transport?

Answer 11

metabolic energy in the form of ATP is needed
substances move against their concentration gradient
carrier proteins which act as pumps are involved.
Process is very selective

Question 12

Describe direct active transport of a single molecule/ion

Answer 12

molecule/ion binds to receptor side of the carrier protein

on the inside of the cell ATP binds to the protein causing it to split into ADP and a phosphate molecule whilst the protein molecule changes shape and opens to the opposite side of the membrane..

molecule/ion released to the other side of the membrane

phosphate molecule is released from the protein so it reverts to its og shape and the phosphate combines with ADP to form ATP during respiration

Question 13

What are two similarities with active transport and facilitated diffusion?

Answer 13

both use carrier proteins

both move molecules that can’t usually move across the bilayer

Question 14

What are two differences with active transport and facilitated diffusion?

Answer 14

AT against concentration gradient, Facilitated diffusion is down

AT requires energy, FD does not