membrane physiology

Question 1

what is fluid outsid ethe cell called?

Answer 1

extracellular fluid

Question 2

what is fluid inside the cell called?

Answer 2

intracellular fluid

Question 3

what are the functions of the cell membrane?

Answer 3

act as a barrier
act as an exchange gateway
act as a communicator for environmental changes
stabilize tissue structure

Question 4

what is the structure of the membrane?

Answer 4

lipid bilayer. hydrophilic head abd hydrophobic tail

Question 5

what type of molecule is EXPLICITLY not allowed to cross the membrane without a channel, carrier or transporter?

Answer 5

an aqueous molecule

Question 6

if a substance can cross the membrane unassisted, what does that mean for the membrane?

Answer 6

the membrane is permeable to it

Question 7

what type of permeability does the cell membrane have?

Answer 7

selective permeability

Question 8

what is a passive force?

Answer 8

forces that do not require cellular energy to produce movement across the membrane

Question 9

what is active force?

Answer 9

forces that require the cell to use energy (ATP)

Question 10

what 2 properties influence a substances permeability to the membrane?

Answer 10

solubility

size

Question 11

can uncharged, non-polar molecules pass the membrane?

Answer 11

yes

Question 12

can charged, polar molecules pass the membrane?

Answer 12

no

Question 13

what 2 forces are passive molecules driven by?

Answer 13

chemical and electrical gradients

Question 14

what is the electrochemical gradient?

Answer 14

when both the electrical and chemical gradients act simultaneously

Question 15

what is diffusion across the lipid bilayer defined as?

Answer 15

simple diffusion

Question 16

will more surface area on the membrane help or hinder diffusion?

Answer 16

help

Question 17

will a thicker membrane help or hinder diffusion?

Answer 17

hinder

Question 18

what is osmosis?

Answer 18

the net diffusion of water down its concentration gradient in the presence of an unequally distributed solute

Question 19

what is tonicity?

Answer 19

the effect of a solution on cell volume

Question 20

what happens to the cell in an isotonic solution

Answer 20

volume remains constant

Question 21

what happens to cell volume in a hypotonic solution?

Answer 21

water rushes in the cell and the cell swells (higher solute concentration inside cel)

Question 22

what happens to cell volume in a hypertonic solution?

Answer 22

water moves out of the cell, the cell shrinks (higher solute concentration outside cell)

Question 23

what is passive transport/facilitated diffusion?

Answer 23

having to use a carrier protein with the concentration gradient

Question 24

what is active transport?

Answer 24

having to use a carrier protein against the concentration gradient

Question 25

what are the 3 characteristics of facilitated diffusion?

Answer 25

specificity
saturation
competition

Question 26

what is the difference between simple diffusion and facilitated diffusion besides the use of a carrier?

Answer 26

simple diffusion: rate of transport is proportion to the amount of solute in the ECF

facilitated diffusion: can only work until the carrier is saturated/reaches a maximum value

Question 27

what is an example of active transport?

Answer 27

the Na-K ATPase pump

Question 28

what is endocytosis?

Answer 28

taking a molcule into the cell via vessicles

Question 29

what is exocytosis?

Answer 29

taking contents into a vessicle and dropping it off at the membrane to leave the cell

Question 30

what is phagocytosis?

Answer 30

when a phagosome (vessicle) eats a particle

Question 31

where are the secretions for exocytosis packaged?

Answer 31

the ER and golgi complex