Plasma membrane

Question 1

is it permeable, non permeable or selectively?

Answer 1

selectively permeable

Question 2

structure of plasma membrane

Answer 2

protein icebergs in a phospholipid sea

Question 3

what are the benefits of it being fluid

Answer 3

proteins and molecules can move around very fast

Question 4

Types of membrane proteins

Answer 4

1) Peripheral - loosely attached
2) Integral - embedded in membrane, partly inside partly outside - inside membrane is hydrophobic and outside is hydrophilic
3) integral transmembrane proteins - inserted in RER as ribisome is making them, outside of it faces into lumen of ER

Question 5

Secretory pathway of transmembrane proteins

Answer 5

go thru ER, into transport vesicles, into golgi and out to plasms mb after exocytosis

Question 6

Passive transport and what can go thru

Answer 6

diffusion of molecules down concentration gradient (high to low), no energy required
small hydrophobic molecules can go through - oxygen and steroids

Question 7

Active transport

Answer 7

Diffusion of molecules up concentration gradient, requires energy

Question 8

how does passive transport work

Answer 8

small hydrophobic molecules can pass through, proteins outside the cell will carry these just outside mb and it is released and diffused into hydrophobic membrane, proteins inside cell will pick it up and suck them into membrane

Question 9

Facilitated diffusion

Answer 9

polar charged molecules cannot go through because of hydrophobic membrane, use transport proteins to get across

Question 10

what are channel proteins and ungated vs gated ones

Answer 10

form a channel for molecules to go through in passive transport
gated channels can be held closed till cell wants to open
ungated channels are always open and can’t close like aquaporin

Question 11

carrier proteins

Answer 11

bind molecule on one side, change shape and release on other side, used for passive and active transport

Question 12

osmosis and aquaporin?

Answer 12

osmosis is diffusion of water

aquaporin is an ungated channel proteins letting water go through

Question 13

hypotonic vs hypertonic and isotonic

Answer 13

hypotonic is a low concentration relative to outside, water flows out
hypertonic - high concentration relative to outside, water flows in
isotonic - equal concentration

Question 14

what does a sodium potassium pump do and what kind of transport

Answer 14

active transport, carrier proteins

pumps 3 Na+ out and 2 K+ in (we have high [Na+] inside and high [K+] outside

Question 15

Conformation 1 of sodium potassium pump

Answer 15

carrier protein facing inside cell, 3Na+ binding sites will bind Na+ with high affinity, 2 K+ binding sites have low affinity for K+

Question 16

Conformation 2 of sodium potassium pump

Answer 16

carrier protein facing outside cell, 3Na+ binding sites have low affinity to Na+, 2 K+ binding sites have high affinity for K+

Question 17

how does phosphorylation control which conformation it is in

Answer 17

if pump is phosphorylated it is in C2

if not phosphorylated it is in C1

Question 18

ATPase activity in pump

Answer 18

can catalyze reaction with ATP to make ADP+P, which gives the energy to pump against the concentration gradient

Question 19

what creates a membrane potential and what is that

Answer 19

difference in charge across a membrane - created bc every pump of Na/K makes the inside of the cell negative so it creates a difference in charge

Question 20

what is an electrogenic pump

Answer 20

ion pumps that create membrane potentials (H+, Na+/K+…)

Question 21

what is an electrochemical gradient

Answer 21

gradient with charge and concentration component - has charge attraction to move things across

Question 22

dendrites purpose

Answer 22

receive info

Question 23

purpose of axon

Answer 23

takes electrical messge away from cell body and to next neuron

Question 24

receiving cell: how does it work for reception of ligand

Answer 24

membrane protein binds to ligand outside of cell, makes receptor change and submit signal inside cell

Question 25

receiving cell: signal transduction

Answer 25

Connects the signal reception process to the cellular response

Question 26

what is cell to cell recognition

Answer 26

when membrane proteins on neighboring cells bind to each other which changes shape of cell and makes a signal

Question 27

Synaptic signaling

Answer 27

signaling between neurons using neurotransmitters

Question 28

Paracrine signaling and why is it important

Answer 28

signaling between 2 non neurons - very important for development for cells to figure out what cell to become as an adult (development of eye)