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Flashcards in Transport Across the Membrane Deck (32)
1

Explain Hydrophobic

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

2

Explain Hydrophilic

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

3

Define Active Transport

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

4

Define the Fluid Mosaic Model

A phospholipid bi-layer studded with large proteins.

5

Explain a glycoproteins role

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

6

Explain a glycolipids role

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

7

Impact of a hypertonic solution on a cell.

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

8

Impact of hypotonic solution on a cell

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

9

Impact of an isotonic solution on a cell

No net movement, doesn't gain or loose water

10

Define a hypertonic solution

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

11

Define a hypotonic solution

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

12

Define an Isotonic solution

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

13

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

Alcohol and steroids (non-polar)

H2O, gases, urea, (small polar)

14

Explain the Fluid Mosaic Model

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

15

Define Osmosis

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.

16

Define a Simple Diffusion

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

17

Define Facilitated Diffusion

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.

18

Define Solute

The solute is dissolved into the solvent
e.g the salt in the saline solution

19

Define Solvent

The substance that the solute gets dissolved into

e.g the water in the saline solution

20

Define Solution

A mixture in which the solute evenly distributed throughout the solvent

21

Explain carrier proteins

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.

22

Define Bulk Transport

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

23

What type of substances use facilitated diffusion.

They are too large
-polar
-uncharged

24

What are the factors affecting permeability

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

25

Define Simple Diffusion

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

26

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

- 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.

27

What are the three key aspects of the cell theory

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

28

What are some distinct features of prokaryotic cells

No membrane bound organelles
No membrane bound nucleus

29

Distinct features of a eukaryotic cell

Distinct membrane bound nucleus
membrane bound organelles

30

What is the role of the cell membrane?

To control movement of molecules in and out of the cell

31

What does the cell membrane consist of

A phospholipid bilayer studded with proteins

32

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

Only allows some subtsances to pass through it