Movement of substances in and out of cells

Question 1

What is diffusion?

Answer 1

The passive movement of particles from an area of high concentration, to an area of low concentration

Question 2

What is osmosis?

Answer 2

The passive, net movement of water molecules from an area of high water potential to an area of low water potential

Question 3

What is active transport?

Answer 3

The active movement of particles through a cell membrane from an area of low concentration to an area of high concentration

Question 4

What type of membrane is the cell membrane?

Answer 4

Partially permeable membrane

Question 5

What makes our cell membrane partially permeable?

Answer 5

It allows some molecules to easily pass through it, but doesn’t allow other molecules to do so

Question 6

Describe what will happen if an animal cell is placed in a hypotonic solution

Answer 6

The water molecules will move into the cell causing it to swell and possibly burst

Question 7

Describe what will happen if an animal cell is placed in a hypertonic solution

Answer 7

The water molecules will move out the cell causing it to shrink and shrivel up

Question 8

What is cell lysis?

Answer 8

The breakdown of a cell caused by damage to its membrane

Question 9

What organelle in a plant cell prevents cell lysis?

Answer 9

Cell wall

Question 10

Where is the water stored in a plant cell?

Answer 10

In its vacuole

Question 11

Give an example of active transport in animal cells?

Answer 11

The absorption of food molecules in the small intestine

Question 12

Give an example of active transport in plant cells?

Answer 12

Root hair cells use active transport to move mineral ions like magnesium or nitrate ions into the cell

Question 13

What do magnesium ions do in a plant cell?

Answer 13

Make chlorophyll

Question 14

What do nitrate ions do in a plant cell?

Answer 14

Make amino acids (to make proteins)

Question 15

Name all the factors that affect the movement of substances in and out of cells?

Answer 15

• Temperature
• Diffusion distance
• Concentration gradient
• Surface area to volume ratio

Question 16

What effect does temperature have?

Answer 16

• Increase KE energy of particles
• Particles move quicker
• More collisions between molecules and membrane

Question 17

What effect does diffusion distance have?

Answer 17

• A lower diffusion distance will allow molecules to diffuse quicker
• This is why capillaries and alveoli are 1-cell thick

Question 18

What effect does concentration gradient have?

Answer 18

• Higher concentration gradient will increase rate of movement
• Area of high concentration will have more molecules, so more collisions between them and the membrane

Question 19

What effect does surface area to volume ratio have?

Answer 19

• A higher SA:V ratio will increase rate of movement
• This adaptation is seen in root hair cells and the villi in small intestine