Movement into and out of cells

Question 1

Define diffusion

Answer 1

the net movement
of particles from a region of their higher
concentration to a region of their lower
concentration (i.e. down a concentration
gradient), as a result of their random movement

Question 2

Where does energy from diffusion come from?

Answer 2

kinetic energy of random movement of
molecules and ions

Question 3

State that some substances move into and out of
cells by diffusion through…

Answer 3

cell membranes

Question 4

Describe the importance of diffusion of gases and
solutes in living organisms

Answer 4

Diffusion is important to cells because it allows them to gain the useful substances they require to obtain energy and grow, and lets them get rid of waste products.

Question 5

state the factors that influence diffusion

Answer 5

surface area, temperature,
concentration gradient and distance

Question 6

Describe the role of water

Answer 6

solvent in organisms with reference to digestion, excretion
and transport

Question 7

Describe osmosis

Answer 7

net movement of
water molecules from a region of higher water
potential (dilute solution) to a region of lower
water potential (concentrated solution), through
a partially permeable membrane

Question 8

describe the effects on red blood cells of immersing them in solutions of different concentrations

Answer 8

Red blood cells placed in a solution with a higher water concentration compared to their contents (eg pure water) will gain water by osmosis, swell up and burst.

Water will diffuse from a higher water concentration outside the cell to a lower water concentration inside the cell.

Red blood cells placed in a solution with a lower water concentration compared to their contents (eg 1.7 per cent salt solution) will lose water by osmosis and shrink.

Water will diffuse from a higher water concentration inside the cell to a lower water concentration outside the cell.

Question 9

water diffuses through…

Answer 9

partially
permeable membranes by osmosis

Question 10

State that water moves into and out of cells by …

Answer 10

osmosis through the cell membrane

Question 11

what are plants are supported by?

Answer 11

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

Question 12

Describe active transport

Answer 12

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

Question 13

Explain the importance of active transport

Answer 13

process for movement of molecules or ions
across membranes, including ion uptake by root
hairs

Question 14

State that protein carriers move molecules or
ions across a membrane during…

Answer 14

active transport

Question 15

What does a turgid cell refer to?

Answer 15

refers to cells or tissues that are swollen from water uptake

Question 16

What does flaccid cell refer to?

Answer 16

floppy or loose, and cells have drawn in and pulled away from the cell wall.

Question 17

What does a cell that is plasmolyzed really mean mean?

Answer 17

This is when the cytoplasm shrinks due to the loss of water but the cell wall fails to shrink due to its tough structure. The cytoplasm eventually tears away from the cell wall.

Question 18

What is turgor pressure?

Answer 18

pressure from fluid within the cell pushing against the cell wall

Question 19

Investigate and describe the effects on plant
tissues of immersing them in solutions of
different concentrations

Answer 19

Plant cells placed in a solution with an equal water concentration to the contents of their cytoplasm and vacuole (dilute sugar solution) will not experience an overall change in volume. No osmosis occurs.

Plant cells placed in a solution with a low water concentration compared to their contents (concentrated sugar solution) will lose water by osmosis. Their cell membranes will peel away from their cell walls and they are said to be plasmolysed.

Water will diffuse from a higher water concentration inside the cell to a lower water concentration outside the cell.

Plant cells placed in a solution with a high water concentration compared to their contents (eg pure water) will gain water by osmosis and swell up until their cytoplasm and cell membrane are pushing against their cell wall. They are said to be turgid.

Water will diffuse from a higher water concentration outside the cell to a lower water concentration inside the cell. The presence of the plant cell wall prevents plant cells from bursting.

Question 20

concentration gradient define it

Answer 20

The difference in concentration between two solutions, between different cells or between cells and a surrounding solution

Question 21

why is diffusion of gases important?

Answer 21

because it allows for gas exchange in organisms to provide useful gases for processes like respiration and for the removal of waste materials

Question 22

Why is diffusion of solutes important?

Answer 22

useful for uptake of solutes from soil by plants

Question 23

How does the concentration gradient affect rate of diffusion?

Answer 23

greater the concentration gradient, the faster the diffusion

Question 24

How does the surface area of the membrane affect rate of diffusion?

Answer 24

as surface area increases, so does the rate of diffusion as there is more space for particles to move throgh

Question 25

How does the diffusion distance affect the rate of diffusion??

Answer 25

the larger the diffusion distance the slower the diffusion as particles have to move further

Question 26

What is a hypotonic sol?

Answer 26

it is one that has a higher water potential than the water potential of the cell

Question 27

What happens when you plane an animal cell in a hypotonic sol?

Answer 27

net movement inside cell since concentration is lower there and leads for cell to burst

Question 28

What happens if you place a plant cell in a hypotonic sol?

Answer 28

net movement inside cell since lower concentration but instead of bursting it becomes turgid since strong cell wall prensece

Question 29

what is a hypertonic sol?

Answer 29

sol with a lower water potential than one inside the cell

Question 30

what happens if you place an animal cell in a hypertonic sol?

Answer 30

net movement out of the cell making it shrink

Question 31

what happens if you place a plant cell in a hypertonic sol?

Answer 31

net movement out of the cell making it plasmolyzed meaning that the cell membrane peels away from the cell

Question 32

what is an isotonic sol?

Answer 32

a sol that has the same water potential as the water potential of a cell

Question 33

What happens if you put a cell inside an isotonic sol

Answer 33

no net movement

Question 34

how is a plant cell supported?

Answer 34

cell wall
and vacuole creates pressure supporting the cell

Question 35

state examples of active transport in humans

Answer 35

mineral and nutrient uptake in the small intestine
reabsorption in kidney

Question 36

state an example of active transport in plants

Answer 36

uptake of minerals into root hair cells

Question 37

Explain how active transport involved proteins

Answer 37

carrier proteins move substances from 1 side of memebrane to other using energy