Cell Membranes and Signaling

Question 1

membrane proteins allow…

Answer 1

• communication with outside environment
• specialized membrane functions
• some tethered to intracellular structures

Question 2

Intergral membrane proteins

Answer 2

emebeded in membrane

Question 3

Peripheral membrane protein

Answer 3

loosely attached

Question 4

6 Membrane Protein functions

Answer 4

1) transport channels
2) receptors for signal transduction (nothing passes through membrane, more message is passed on causing other things to trigger)
3_cytoskeleton attachment
4) enzyme activity
5) intracellular attachment (cellular adhesion of molecules)
6) cell-cell recognition

Question 5

amphipathic

Answer 5

partially hydrophobic, partially hydrophilic

Question 6

what can just pass through membrane?

Answer 6

lipid soluble

Question 7

fluid mosaic model

Answer 7

some of the membranes move sideways within the pane of the plasma membrane

Question 8

fluid membrane

Answer 8

unsaturated (kinks)

Question 9

viscous membrane

Answer 9

saturated (no kinks, packed tightly)

Question 10

cholesterol…

Answer 10

reduces membrane fluidity at moderate temps but hinders solidification at low temps

Question 11

an ice dwelling fish would…

Answer 11

have higher UNSATURATED fatty acids (harder to solidify)

Question 12

diffusion:

Answer 12

substances move until they are equally and randomly distributed –> equilibrium

Question 13

simple diffusion

Answer 13

:solutes move, ALWAYS move down concentration gradient

Question 14

osmolarity

Answer 14

concentration metric, # of molecules per volume f fluid

Question 15

osmosis

Answer 15

movement o water to equalize osmolarity (when salute cant pass, water will)

Question 16

tonicity

Answer 16

ability of solution to alters cells water volume

Question 17

plasmolyzed (plants)

Answer 17

shriveled (humans)

Question 18

aquaporins

Answer 18

channel specifically for water

Question 19

channel

Answer 19

mediated diffusion
- ion gated
-voltage gated

Question 20

active transport

Answer 20

moves molecules against their concentration gradient, requires a carrier and energy input

Question 21

carrier mediated diffusion

Answer 21

physically moves large molecules

Question 22

co-transport

Answer 22

uses stored energy from active transport
1) active transport pumps ions uphill, creating a concentration gradient
2) the ions are allowed to flow down their concentration gradient
(builds concentration gradient in order to do other work)

Question 23

vesicular (bulk) transport

Answer 23

endocytosis (bring inside)
exocytosis (taking cell outside)

Question 24

electrogenic pump

Answer 24

contributes to voltage difference across plasma membrane

Question 25

Local signaling

Answer 25

gap junctions
cell-cell recognition
paracrine(local regulator synaptic

Question 26

long distance signaling

Answer 26

endocrine
nervous tissue

Question 27

3 stages of cell signaling

Answer 27

1) reception: recognizing the signal molecule
2) transduction: convert original signal into form that can trigger cellular response
3) response: finally it triggers specific activity

Question 28

ligand

Answer 28

signaling molecule that binds to another specific molecule
1) plasma membranes
2) intracellular receptors

Question 29

G protein coupled receptor

Answer 29

• utilizes transmembrane receptors
• binds GTP (energy shuttle molecule similar to ATP) to a G protein
• activates another enzyme

Question 30

ligand ion channel

Answer 30

• channel only opens with specific ligand binds
• allows movement of molecules that may trigger intracellular response

Question 31

intracellular receptors

Answer 31

lipid soluble signal scan diffuse through plasma membrane!
ex. steroids

Question 32

phosphorylation cascade

Answer 32

protein kinase: transfer a phosphate group –> phosphorylate –> active

protein phosphate: remove a phosphate group –> deactivate