Midterm 3

Question 1

cell membranes

Answer 1

selective barriers for receiving info, motility, molec import/export

Question 2

arrangement of ambiphatic lipids and proteins in a biological membrane

Answer 2

lipid bilayer of phospholipids with hydrophilic heads and hydrophobic tails

Question 3

water forms a cage-like structure around

Answer 3

hydrophobic molecs

Question 4

hydrophilic molecs

Answer 4

form bonds with w

Question 5

phospholipids form what in water

Answer 5

liposome

Question 6

bilayer and flip-flop

Answer 6

lipids can move laterally but rarely flip flop

Question 7

2 properties that affect membrane fluidity

Answer 7

1. length of carbon bond (shorter = more fluid, longer = less fluid)
2. # of double bonds (unsaturated has double bond = more fluid, saturated has none = less fluid)

Question 8

proteins can be associated with the membrane by

Question 9

asymmetric distribution of phospholipids is caused by

Answer 9

scramblases and flippases

Question 10

proteins fabricated in the non-cytosolic/lumen will be transported to

Answer 10

the plasma membrane (extracellular space)

Question 11

cytosolic facing proteins

Answer 11

remain cytosolic

Question 12

membrane domains are formed

Answer 12

by tethering proteins to structures inside/outside the cell

Question 13

glycocalyx

Answer 13

carbohydrate layer on plasma membrane

Question 14

functions of sugars in glycocalyx

Answer 14

protects the cell from mechanical damage and functions in cell-cell recognition and adhesion

Question 15

what major ions are in high concentration inside cells

Answer 15

K+, Na+, Cl-

Question 16

which molecs will diffuse fastest across a lipid membrane

Answer 16

smaller, hydrophobic

Question 17

simple diffusion

Answer 17

molecs move from one location to another by random, thermally driven motion

Question 18

passive transport

Answer 18

spontaneous movement of a solute down its electrochem grad

Question 19

active transport

Answer 19

movement of a solute across its electrochem grad (uses E)

Question 20

ion channels

Answer 20

allows ions through a channel based on size/electric charge

Question 21

ion transporters

Answer 21

transport ions/molecs that fit into specific binding site

Question 22

concentration gradients and electrochem forces drive passive transport via

Answer 22

electrochem grad

Question 23

3 mechanisms for moving solutes against their electrochem grads

Answer 23

1. coupled pumps
2. ATP-driven pumps
3. light-driven pumps

Question 24

Na/K pump

Answer 24

Na+ out, 2K+ in - uses ATP; high Na+ outside high K+ inside

Question 25

Ca2+ pump

Answer 25

pumps out of the cell using ATP (cell comm. and muscle contraction)

Question 26

Na+ and glucose transporter on gut cells

Answer 26

uses import of Na+ to import glucose

Question 27

what electrochem grad is used to import/export solutes in plants/bacteria/fungi

Answer 27

electrochem H+ grad

Question 28

ion channel selectivity

Answer 28

only those with appropriate size and charge will pass

Question 29

voltage-gated ion channels

Answer 29

controlled by membrane potential

Question 30

ligand-gated ion channels

Answer 30

opening controlled by binding of the ligand

Question 31

mechanically-gated ion channels

Answer 31

controlled by mechanical force

Question 32

a trace from a patch clamp recording

Answer 32

shows current over time passing thru membrane channels

Question 33

resting potential of the cell is established

Answer 33

differences in voltage across plasma membrane

Question 34

action potential

Answer 34

traveling wave of electrical excitation used to carry messages by neurons

Question 35

how do neurons transmit signals across synapses

Answer 35

triggered by the entry of Ca2+ in the postsynaptic cell that can adjust the amount of neurotransmitter released, or adjust how the postsynaptic cell responds

Question 36

drugs

Answer 36

blocks uptake or makes channels easier to open

Question 37

optogenetics

Answer 37

uses light to control the neurons that have light-gated ion channels