Transport

Question 1

What is diffusion?

Answer 1

Movement of particles from an area of high concentration to an area of low concentration, down a concentration gradient

Question 2

Does diffusion require energy?

Answer 2

No

Question 3

What is a concentration gradient?

Answer 3

The difference in concentrations between two different places

Question 4

What is osmosis?

Answer 4

Movement of water molecules from an area of high water concentration (dilute solution) to an area of low water concentration (concentrated solution) down a concentration gradient, through a partially permeable membrane.

Question 5

Which molecules undergo osmosis?

Answer 5

Water

Question 6

What is a partially permeable membrane?

Answer 6

A membrane which will allow certain molecules through, but not others. e.g. a cell membrane

Question 7

You are investigating osmosis in potato slices, by putting slices of potato into solutions with different sugar concentrations. How could you determine whether osmosis had taken place?

Answer 7

By measuring the mass of the potato before and after. If the mass has changed, this is due to osmosis.

Question 8

You are investigating osmosis in potato slices, by putting slices of potato into solutions with different sugar concentrations. If the potato slice has lost mass whilst in sugar solution, in which direction has osmosis taken place? What conclusion can you draw about the sugar solution?

Answer 8

Water has moved out of the potato and into the sugar solution. This means the concentration of water is higher in the potato than in the sugar solution (or the sugar solution is more concentrated than the potato).

Question 9

You are investigating osmosis in potato slices, by putting slices of potato into solutions with different sugar concentrations. If the potato slice has gained mass whilst in sugar solution, in which direction has osmosis taken place? What conclusion can you draw about the sugar solution?

Answer 9

Water has moved out of the solution into the potato. This means the concentration of water is higher in the sugar solution than in the potato (or the potato is more concentrated than the sugar solution).

Question 10

You are investigating osmosis in potato slices, by putting slices of potato into solutions with different sugar concentrations. Suggest some control variables

Answer 10

Mass of potato, surface area of potato slice, temperature of solution, time the solution and potato were left for

Question 11

Does osmosis require energy?

Answer 11

no

Question 12

What is active transport?

Answer 12

Movement of particles from an area of low concentration to an area of high concentration.

Question 13

Does active transport require energy?

Answer 13

yes

Question 14

How is percentage change in mass calcualted?

Answer 14

=change in mass / original mass x 100

Question 15

Which chemical reagent is needed to test for the presence of glucose in a food?

Answer 15

Benedicts

Question 16

What colour change does Benedicts solution undergo if glucose is present?

Answer 16

from blue -> orange/red

Question 17

Which chemical reagent is needed to test for the presence of starch in a food?

Answer 17

Iodine

Question 18

What colour change does iodine solution undergo if starch is present?

Answer 18

brown-> blue-black

Question 19

Which chemical reagent is needed to test for the presence of protein in a food?

Answer 19

Biuret reagent

Question 20

What colour change does biuret reagent undergo if protein is present?

Answer 20

blue –> purple

Question 21

Which chemical is needed to test for the presence of fat in a food?

Answer 21

ethanol and water

Question 22

What colour change does ethanol followed by water undergo if fat is present?

Answer 22

colourless –> cloudy/white

Question 23

How can you determine how much energy is in a certain food?

Answer 23

Burn the food underneath a boiling tube of water. Measure the temperature change in the water using a thermometer.