3. Movement into and out of cells

Question 1

What is diffusion?

Answer 1

net movement of particles from a region of higher concentration to a region of their lower concentration (down a concentration gradient), due to their random movement

Question 2

What influences the rate of diffusion?

Answer 2

• temperature
• distance
• surface area
• concentration gradient

Question 3

What is the concentration of a solution?

Answer 3

How much solute is dissolved in the solvent.

Question 4

What is osmosis?

Answer 4

net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane

Question 5

What is active transport? What does it need?

Answer 5

movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration (against a concentration gradient) using energy from respiration

Question 6

Where does the energy for diffusion come from?

Answer 6

kinetic energy of random movement of molecules and ions

Question 7

How can substances move into and out of cells?

Answer 7

by diffusion through the cell membrane

Question 8

What are some roles of water in the body?

Answer 8

digestion, excretion and transport

Question 9

How does water diffuse through partially permeable membranes?

Answer 9

osmosis

Question 10

Water _______ by osmosis.

Answer 10

diffuses through partially permeable membranes

Question 11

How does water move into and out of cells?

Answer 11

by osmosis through the cell membrane

Question 12

What is turgor pressure?

Answer 12

water pressure inside a plant cell that presses against the cell wall

Question 13

What does turgid mean?

Answer 13

sufficient turgor pressure to keep plant cell stiff

Question 14

What does flaccid mean?

Answer 14

turgor pressure is insufficient in plant cell due to loss of water by osmosis

Question 15

What does plasmolysis mean?

Answer 15

plant cell in a concentrated solution, cytoplasm shrinks so much that cell membrane is pulled away from the cell wall

Question 16

Why is active transport important?

Answer 16

it is a process for movement of molecules or ions across membranes

Question 17

Give one example of active transport.

Answer 17

ion uptake by root hairs

Question 18

What do protein carriers do?

Answer 18

move molecules or ions across a membrane during active transport

Question 19

How are plants supported?

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Answer 19

by the pressure
of water inside the cells pressing outwards on the
cell wall