Membrane transport

Question 1

Plasma membrane

Answer 1

Boundary of cell - encloses and supports cell contents
Separates intracellular vs extracellular materials
Fluid mosaic model
Attaches cells to other cells, to the surrounding matrix
Cell communicate with others through cell membrane
Determines what can move in and out of cell (selectively permeable)
Membrane potential

Question 2

Channel proteins

Answer 2

Form tiny channel through the plasma membrane
Molecules of certain size, shape and charge can pass through
Non-gated ion channels - always open
Gated ion channels - open/closed by certain stimuli

Question 3

Carrier proteins

Answer 3

(Transporters)
Integral proteins move ions from one side of membrane to other
- specific binding sites
- protein changes shape to transport ions or molecules
- resumes original shape after transport
- uniporters, symporters, antiporters

Question 4

Solute

Answer 4

Dissolved substance in solution

Question 5

Solvent

Answer 5

Liquid that holds solutes (usually water)

Question 6

Solution

Answer 6

Mixture formed when solute is dissolved in solvent

Question 7

ATP powered transport

Answer 7

Requires energy in the form of ATP

Transports substances against their concentration gradient, so cell can accumulate substances - sodium potassium pump

Question 8

Diffusion

Answer 8

Molecules move from an area of higher conc to lower conc

Continues until the molecules have evenly distributed themselves throughout the solution

Question 9

Diffusion through Cell Membrane

Answer 9

• Certain specific non-lipid soluablle molecules/ions diffuse through membrane channels
• Other non-lipid soluble molecules can’t enter cell
• Lipid soluble molecules diffuse directly though plasma membrane

Question 10

Facilitated diffusion

Answer 10

Move large, water soluble molecule or electrically charged molecules across plasma membrane
Amino acids and glucose in, manufactured proteins out
Passive

Question 11

Osmosis

Answer 11

Diffusion of water across a selectively permeable membrane
Effect of the concentration of the solution - determines how much water moves across the membrane
more concentrated a solution, more water will move into the solution - strong pull

Question 12

Osmolarity

Answer 12

The pull on water created by solutes
Measured in Osmoles/L
Weak solution - low osmolarity value
Concentrated solution - high osmolarity value

Question 13

Osmolarity of intracellular fluid

Answer 13

290 osmoles/L

Question 14

Isotonic Solutions

Answer 14

Solution has the same osmolarity as inside of cell - water will move between cell and solution at equal rates

Question 15

Hypotonic solution

Answer 15

Solution has lower osmolarity than cell - water moves into cell