2.4 Movement of substances in and out of cells

Question 1

Diffusion

Answer 1

the net movement of substances from an area of high water potential to low water potential

Question 2

Osmosis

Answer 2

the net movement of water from an area of high water potential to low water potential through a partially permeable membrane

Question 3

Active transport

Answer 3

the movement of substances from an area of low to high concentration, against a concentration gradient, using the energy from ATP

Question 4

Concentration Gradient

Answer 4

the difference in concentration between two areas

Question 5

Surface area to volume ratio

Answer 5

the size of the object compared with the area that is in contact with the environment

Question 6

Isotonic solution

Answer 6

the solution outside the cell has the same water potential as inside the
cell - no net movement

Question 7

Hypotonic solution

Answer 7

the solution outside the cell has a higher water potential then inside
the cell - net movement of free water molecules into the cell

Question 8

Hypertonic solution

Answer 8

the solution outside the cell has a lower water potential then inside
the cell - net movement of free water molecules out of the cell

Question 9

When placed in a Hypotonic solution, state what would happen and the name given to both a plant and an animal cell

Answer 9

plant: turgid (normal) (cell wall prevents bursting)

animal: lysed (bursts because no cell wall to provide strength and maintain structure)

Question 10

When placed in a Hypertonic solution, state what would happen and the name given to both a plant and an animal cell

Answer 10

plant: plasmolysed (wilt, not enough water to fill their cells therefore cytoplasm shrinks from the cell wall)

animal: shrivelled

Question 11

Potato chips in a sucrose solution experiment method:

Answer 11

Potato chips can be placed in sucrose or salt
solutions of different concentrations.
1. put potato chips of the same size in sucrose or salt solutions of different concentrations
2. Osmosis will occur until the water potential
of the tissue and solution are the same; this
causes a mass change
–> If the solution has a higher water
concentration, water will move into
the potato chip and the mass will
increase
–> If the solution has a lower water
concentration, water will move out of
the potato chip and the mass will
decrease

Question 12

Examples of biological molecules

Answer 12

Glucose is absorbed by active transport in the small intestine
plants use active transport in their root hair cells to absorb mineral ions.

Question 13

Describe an experiment to show how different concentrations of a solution affect the appearance of plant cells

Answer 13

immerse onion epidermis
same volume of solutions
at least two different concentrations of solution
leave cells for the same amount of time
observe under microscope