Transport Across the Membrane

Question 1

Explain Hydrophobic

Answer 1

-Non-polar
Means fearing water
e.g the fatty acid tails in the cell membrane are non-polar

Question 2

Explain Hydrophilic

Answer 2

• Polar
• Means water loving
  e. g the phosphate heads are hydrophobic in the cell membrane

Question 3

Define Active Transport

Answer 3

The movement of molecules from a region of low concentration to a region of high concentration, requiring the energy in the form of ATP.

Question 4

Define the Fluid Mosaic Model

Answer 4

A phospholipid bi-layer studded with large proteins.

Question 5

Explain a glycoproteins role

Answer 5

Cellular recognition (self or non-self) and signalling molecules

Question 6

Explain a glycolipids role

Answer 6

They are receptors and markers and are essentially carbohydrate rings bonded to a lipid.

Question 7

Impact of a hypertonic solution on a cell.

Answer 7

Loose water, animal cells will become shrivelled and plant cells will undergo plasmolysis

Question 8

Impact of hypotonic solution on a cell

Answer 8

Gain water, animal cells will expand and can lyse (burst). Plant cells expand however the cell wall prevents it from rupturing.

Question 9

Impact of an isotonic solution on a cell

Answer 9

No net movement, doesn’t gain or loose water

Question 10

Define a hypertonic solution

Answer 10

Has a higher solute concentration than the solution it is compared with. (Cell will loose water)

Question 11

Define a hypotonic solution

Answer 11

Has a lower solute concentration than the solution it is being compared with (Cell will gain water)

Question 12

Define an Isotonic solution

Answer 12

Has the same solute concentration as the solution being compared with.

Question 13

Examples of molecules that can pass through a membrane via simple diffusion.

Answer 13

Alcohol and steroids (non-polar)

H2O, gases, urea, (small polar)

Question 14

Explain the Fluid Mosaic Model

Answer 14

Cell membranes consist of a bi-layer of phospholipids with embedded proteins floating throughout.

Question 15

Define Osmosis

Answer 15

The passive net movement of water molecules from a region of low solute concentration to a region of high solute concentration, through a semi-permeable membrane.

Question 16

Define a Simple Diffusion

Answer 16

The passive net movement of molecules across a semi-permeable membrane from areas of high concentration to areas of low concentration.

Question 17

Define Facilitated Diffusion

Answer 17

The passive net movement of molecules across a semi-permeable membrane, via protein channels or protein carriers. The molecules, are moving from areas of high concentration to areas of low concentration.

Question 18

Define Solute

Answer 18

The solute is dissolved into the solvent

e.g the salt in the saline solution

Question 19

Define Solvent

Answer 19

The substance that the solute gets dissolved into

e.g the water in the saline solution

Question 20

Define Solution

Answer 20

A mixture in which the solute evenly distributed throughout the solvent

Question 21

Explain carrier proteins

Answer 21

Upon binding with a SPECIFIC molecule, carrier proteins create an opening in the lipid bi-layer by undergoing a conformational change, thus enabling the larger and more polar molecules to exit.

Question 22

Define Bulk Transport

Answer 22

Vesicle mediated active transport that involves the movement of large particles across the cell membrane.

Question 23

What type of substances use facilitated diffusion.

Answer 23

They are too large

• polar
• uncharged

Question 24

What are the factors affecting permeability

Answer 24

Temperature, state of substance, surface area and composition of a membrane.

Question 25

Define Simple Diffusion

Answer 25

The passive net movement of molecules across a semi-permeable membrane from areas high concentration to areas of low concentration.

Question 26

Why is the properties of the phospholipid bi-layer important to the structure of the membrane.

Answer 26

• Sufficient flexibility to form vesicles around particles to be transported
• Ability to move laterally to allow the folding of the membrane
• Allows passage of lipid-soluble molecules.
• Makes the membrane strong and hard to break.

Question 27

What are the three key aspects of the cell theory

Answer 27

• All living organisms are comprised of cells
• Cells are the basic unit function of life
• All new cells arise from pre-exsisting cells

Question 28

What are some distinct features of prokaryotic cells

Answer 28

No membrane bound organelles

No membrane bound nucleus

Question 29

Distinct features of a eukaryotic cell

Answer 29

Distinct membrane bound nucleus

membrane bound organelles

Question 30

What is the role of the cell membrane?

Answer 30

To control movement of molecules in and out of the cell

Question 31

What does the cell membrane consist of

Answer 31

A phospholipid bilayer studded with proteins

Question 32

What is it mean by the cell membrane is semi-permeable?

Answer 32

Only allows some subtsances to pass through it