cell membrane + passive transport

Question 1

lipid bilayers are more permeable to ______ ______ and to _____ _____

Answer 1

small molecules (CO2, /H2O), NP substances (bilayer has a np interior, so like attracts like)

Question 2

what are the 2 mechanisms/types for transport?

Answer 2

passive
active

Question 3

what is the special characteristic of passive transport?

Answer 3

molecules move naturally (no energy required) from high to low concentration

Question 4

what is the passive transport of water across the membrane called?

Answer 4

osmosis

Question 5

hypertonic vs hypotonic vs isotonic

Answer 5

hyper: more solute less water, RBC shrink
hypo: less solute more water, RBC lyse
iso: solute = water, rbc happy

Question 6

facilitated diffusion

Answer 6

while osmosis only focuses on water transport, facilitated diffusion refers to the transport of everything else

Question 7

how does concentration, molecular size, and temperature influence the SPEED of facilitated diffusion?

Answer 7

concentration: the more difference of concentration between 2 areas, the faster the speed of diffusion

molecular size: smaller molecules diffuse faster

temperature: the higher the temp, the higher the KE, so the diffusion rate is faster

Question 8

when is equilibrium reached?

Answer 8

when molecules stop moving in one direction

Question 9

what are the two types of protein for facilitated diffusion?

Answer 9

Carrier proteins + Channel proteins

Question 10

what are carrier proteins? why are they sometimes called uniporters?

Answer 10

lets thru specific POLAR molecules (ex: sugar + amino acids) by binding solute molecules on one side and releasing on other
called uniporter bc can transport only 1 to 2 things at a time

ex: glucose transporter on RBC

Question 11

what are channel proteins? how many subtypes are there?

Answer 11

straightforward passage
3 types, pores, gated, and aquaporin

Question 12

what are pores?

Answer 12

a channel protein under facilitated diffusion
large nonspecific channels made of porins

Question 13

what are gated channels? what do they transport? what is opening/closing based on?

Answer 13

channels that work like a open/close gate + transport ions
opening/closing is based on binding sites + size filter

Question 14

what are the 3 types of gated channels? (v, l, m)

Answer 14

voltage channel: voltage based

ligand channel: specific ligand binding based

mechanosensitive channel: pressure on receptor based

Question 15

what is an aquaporin? is it selective or no?

Answer 15

simple channel that transports water
no, always open

Question 16

integral membrane proteins (2 types) + describe each + how do c and n-terminus apply to them

Answer 16

integral monotropic: embedded on one side
transmembrane: protrudes on both sides
single pass: c on one end, n on other
multipass: crosses multiple times, c and n terminus can be on same or diff sides (ex: 7 tm)

Question 17

peripheral proteins, location + hydro phobic or philic?

Answer 17

think of location; since they stay on the surface of the membrane, and the membrane is polar, these guys have to be hydrophilic because they’re gonna deal with a lot of water
don’t penetrate bilayer
bound to membrane w weak electrostatic forces + h-bonds
spectrin is a peripheral protein of RBC’s

Question 18

what is glycosylation + why is it important?

Answer 18

its post translational modification, addition of glycans to a membrane protein
its important bc it determines protein structure + function