Movement in and out of cells

Question 1

Define diffusion

Answer 1

The net movement of a substance, by random motion from a region of high concentration to region of low concentration.

Question 2

Name some substances that move via diffusion into and out of cells

Answer 2

Oxygen, Carbon dioxid, sugars (glucose), waste products (urea)

Question 3

Define osmosis

Answer 3

Osmosis is the diffusion of water from a dilute to a more concentrated solution through a partially permeable membrane

Question 4

What is a partially permeable membrane?

Answer 4

A partially-permeable membrane is a membrane that allows small particles such as water molecules through it, but not larger particles such as sugar molecules and ions from salts

Question 5

Name the only substance that moves via osmosis

Answer 5

Water

Question 6

Define active transport

Answer 6

Active transport is the process by which substances are absorbed against a concentration gradient. This requires the use of energy from respiration.

Question 7

How are diffusion and active transport different?

Answer 7

Diffusion is the movement of particles from a high to a low concentration. Active transport is from a low to a high concentration. Active transport requires energy, diffusion does not

Question 8

In the potato osmosis required practical what was measured (dependent variable)?

Answer 8

The mass of the potato piece before and after going into solution. The length of the potato piece before and after going into solution

Question 9

In the potato osmosis required practical what was the independent variable?

Answer 9

The concentration of the salt solution

Question 10

In the potato osmosis required practical what were the control variables?

Answer 10

Same volume of salt solution
Same initial size of potato pieces
Same amount of time the potato pieces were left in the solution

Question 11

How does temperature effect the rate of diffusion?

Answer 11

An increase in temperature means that particles move around more quickly. When this happens diffusion takes place more rapidly as the random movement or particles speeds up

Question 12

How do microvilli effect the rate of diffusion?

Answer 12

Microvilli increase the rate of diffusion as they increase the surface area of the cell

Question 13

What does dilute mean?

Answer 13

A dilute solution contains a relatively high concentration of water

Question 14

What does concentrated mean?

Answer 14

A concentrated solution contains a relatively low concentration of water