Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCBM > Biological membranes > Flashcards

Biological membranes Flashcards

1
Q

What are membrane functions

A
  1. barrier
  2. cellular organization
  3. transport
  4. signal transduction
  5. cell-cell communication
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

membrane lipids are ____which mean they have a hydrophobic and hydrophilic component.

A

amphipathic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the hydrophobic and hydrophilic region of glycerophospholipid

A

diacylgycerol; phosphorylated alcohol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the hydrophobic and hydrophilic region of sphingomyelin

A

ceramide; phosphorylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the hydrophobic and hydrophilic region of glycosphingolipid

A

ceramide; sugar residues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the hydrophobic and hydrophilic region of cholesterol

A

hydrocarbon rings; OH group at carbon 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Inner and outer leaflets of single membranes have different compositions:

A

One layer exposed to environment and one layer exposed to interior of cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What gets flipped out to exterior of cell during apoptosis and serves as a signal for phagocytosis

A

Phosphatidylserine; usually very little on outer leaflet, entirely internal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does flipase do

A

move PE (phosphatidylehanolamine) and PS (phosphatylserine) from outer to cystolic leaflet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does amount of membrane movement depend on

A

percentage of unsaturated fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does floppase do

A

moves phospholipids from cystolic to outer leaflet (one used by phosphotidylserine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do scramblase’s do

A

moves lipids in either direction, toward equilibrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What physical factors affect fluidity of membrane

A
  1. temperature
  2. pressure
  3. membrane potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what chemical factors affect fluidity of membrane

A
  1. head group of phospholipid
  2. FA chain length
  3. FA unsaturation
  4. cholesterol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what indirect factors affect fluidity of membrane

A
  1. hormones
  2. adaptation to stress
  3. cell cycle
  4. cell differentiation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Unsaturated has more fluidity bc:

A

they cannot pack as tightly as saturated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

% of saturated fats affects melting temp bc:

A

more long chain saturated fats inc melting temp due to packing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Lateral diffusion of cell-surface proteins is very fast:

A
  1. virus induced fusion

2. mixture of labeled proteins from the membranes in heterokaryon (hybrid cell)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Flourescence recovery after photobleaching is a techniqe to monitor lateral diffusion of lipids and proteins in membranes. How does it work?

A
  1. Shine light on it –> bleaches out flourescence
  2. Fourescence intensity goes very down
  3. Wait and it starts to recover as other still labeled monomers come to that region
    - This shows that there is a lot of movement within our membranes.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the fluid mosaic model

A

lipid bilayer composed of phospholipids and sphingolipids. There are peripheral proteins, integral proteins, glycolipids

21
Q

what are the membrane proteins

A
  1. peripheral
  2. amphitropic
  3. integral
  4. lipid (GPI) -linked
22
Q

What are amphitropic proteins

A

proteins that bind loosely to suruface of lipid bilayer and can be released.

23
Q

what is a glycophorin

A

a well characterized membrane protein of RBC’s.

  1. Hydrophobic domain
  2. Hydrophillic domain (intracellular)
  3. Membrane spanning (hydrophobic)
24
Q

what are integral proteins

A

All have an alpha helical, hydrophobic region of aa that will be the membrane spanning portion.

25
Q

what are lipid rafts

A

stable microdomains of cholesterol and sphingolipids that can form on either the inner or outer leaflet that serve as sites for lipid -linked protein attachment

26
Q

What is a caveolin

A

protein dimers that are lipid-linked to the cell membrane, they produce invaginations in the cell membrane

27
Q

what processes cause membrane fusion

A
  1. building of vesicles from golgi complexes
  2. exocytosis
  3. endocytosis
  4. viral infection
  5. fusion of sperm and egg
28
Q

what is exocytosis

A

membrane fusion and nuerotransmitter release

29
Q

what proteins does exocytosis use

A

SNARE’s and SNAP25; form zipped up component and keeps pulling it toward fusion until you get an opening for contents of vesicles to be released.

30
Q

what is endocytosis

A
  1. phagocytosis of particulate matter
  2. pinocytosis take up extracellular fluid
  3. receptor mediated endocytosis
31
Q

What is receptor mediated endocytosis

A

LDL receptors bind to LDL particles that cause them to be endocytosed.

32
Q

What is familial hypercholesterolemia

A

People who have defective LDL receptors accumulate high levels of LDL in their blood that cause them to have heart attacks and atherosclerasis

33
Q

What are the 2 types of active transport

A
  1. Primary active transport: Directly use ATP hydrolysis to move things in and out
  2. Secondary active transport: Use ATP hydrolysis to create a conc. gradient that is used to symport other things in and out
34
Q

Lipid bilayer is not a barrier for :

A
  1. gases (oxygen, CO2)
  2. ethanol (polar molecules and small uncharged)
  3. water
35
Q

what can’t cross lipid bilayer

A
  1. large molecules - glucose
  2. ions
  3. polar charged molecules - aa, nucleotides, sugar phosphates
36
Q

What is solute movement across membranes like

A

movement of charged solutes will depend on a combination of chemical and electrical gradients: electrochemical potential

37
Q

Transporter reduces delta G of _____

A

diffusion; makes it more efficient to get it in and out

38
Q

What are the 6 major types of membrane transport

A
  1. Simple diffusion: nonpolar compounds only, down conc gradient (high to low)
  2. Fascilitated diffusion: uses protein; from high to low
  3. Primary active transport: against electrochemical gradient
  4. Secondary active transport:
  5. ion channels:
  6. ionophores:
39
Q

What are general classes of transporters

A
  1. uniporters: carry 1 molecule back and forth
  2. symporter: take 2 molecules in same direction
  3. antiport: taking one in and one out at the same time
40
Q

what is the driving force in Simple diffusion

A

entropy

41
Q

what is hypertonic

A

high salt solution than intracellularly so water diffuses out and cell shrivels

42
Q

what is isotonic

A

salt conc is same inside and out. cell is in equilibrium

43
Q

what is hypotonic

A

higher salt conc inside than outside, so water goes inside cell to make equal conc. cells swell

44
Q

What is a good ex of fasciliated diffusion

A
  1. chloride bicarbonate exchanger. it uses an antiporter

2. GLUT1 Transporter

45
Q

What are three types of Primary active transporters

A
  1. P type: Na/K ATPase, SERCA calcium pumps
  2. F type: uses proton gradient; ex is mitochondrial ATP synthase
  3. ABC Type: dimer with 2 ATPase. Ex: CFTR
46
Q

How does Na/K+ ATPase work

A

Sets up membrane potential. Makes it more negative on the inside and more positive on outside. Ships 3 Na out and 2 K+ in. Low sodium inside, high potassium

47
Q

What are ion channels

A
  1. Resting is always open
  2. Voltage gated: responds to change in membrane potential
  3. Ligand gated: responds to extracellular neurotransmitter
  4. signal gated: responds to int cellular signal transduction events.
48
Q

How do voltage gated K+ channels work

A

Contain R residues that are pulled toward - charged cytosol. When membrane depolarizes, pull is lessened, conformation changes, pore opens.

49
Q

what are ionophores

A

masks charge and shuttle ions across membrane.

MCBM (59 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions