Membrane dynamics

Question 1

intracellular fluid

Answer 1

inside the cell

-high concentration of potassium and proteins

Question 2

Extracellular fluid

Answer 2

plasma and interstitial fluid
interstitial fluid: high in Na and Cl
plasma: high in Na, Cl, and proteins

Question 3

Transport mechanism physical and energy requirements

Answer 3

physical; size, and lipid solubility
energy ; direction your moving it
- flowing down a gradient- passive
--> concentration: uncharged molecules
--> electrochemical: charged molecules
- Moving against gradient - active
--> uses ATP

Question 4

Ficks law

Answer 4

Rate of simple diffusion:
Rate of diffusion = surface area * concentration gradient* membrane permeability
Membrane permeability = lipid solubility/ molecular size

Question 5

Channel proteins that allow water to flow

Answer 5

leakage = open
gated = chemically, mechanically, and voltage
*only for facilitated diffusion

Question 6

Carrier proteins

Answer 6

change confirmation: never form direct connection between intra and extracellular fluids

• slower but can move bigger molecules(glucose & aminos)
• Can be used against a gradient; uniporter, co transporter(sym and antiporter)
• show specificity, competition and saturation
• • can be either passive or active

Question 7

Primary active:

Answer 7

carrier protein, move something against gradient

= utilize ATP directly

Question 8

Secondary active

Answer 8

utilize ATP indirectly

• uses energy stored in concentration gradient(created using ATP) to move something else against gradient.
  ex: SGLT

Question 9

Vesicular transport

Answer 9

endocytosis: bringing something inside the cell (selectice, receptor mediated)
Exocytosis: taking stuff out of the cell; ongoing, regulated usually by Ca++ when you want to release things and when you want to communicate

Question 10

Water movement

Answer 10

cant cross the lipid bilayer, need aquaporins, released by posterior pituitary,

Question 11

vasopressin

Answer 11

released by posterior pituitary; allow rapid movement of water across membrane through the use of aquaporins

Question 12

Osmosis

Answer 12

Water moves across a membrane in response to a solute concentration gradient to equalize concentrations.
- Higher osmolarity = higher concentration so water will flow.

Question 13

isosmotice

Answer 13

equal num of solute particles/unit volume

Question 14

hyperosmotic

Answer 14

more particles /unit volume

Question 15

hyposmotic

Answer 15

fewer particles/unit volume

Question 16

Tonicity

Answer 16

compares solution to cell and predicts H2O movement in/out of cell.

• osmolarity is not enough to determine if osmosis will occur b/c the membrane, may or may not be permeable to the solute
• depends only on concentration of non-penetrating solutes

Question 17

Tonicity: what happens to a cell when the solution and cell are isosmotic?

Answer 17

cell doesn’t change shape

Question 18

Tonicity: what happens when a solution is hypotonic to a cell?

Answer 18

Cells swells

Question 19

Tonicity: what happens to a cell when the solution is hypertonic to a cell?

Answer 19

the cell shrinks