Brainscape's Knowledge GenomeTM

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


See full index

Cell biology > Membrane composition > Flashcards

Membrane composition Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

flippases

A

Move phospholipids from outer to inner leaflet of bilayer
Requires ATP
Highly specific

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

floppases

A

Move phospholipids from inner to outer leaflet of bilayer
Requires ATP
Specific

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

scramblases

A

Move phospholipids in both directions
No ATP needed
Non-specific

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

factors affecting membrane fluidity

A

Temperature
Acyl chain length
Acyl chain saturation

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

Effect of temperature on membrane fluidity

A

cold=rigid/less fluid
so at cold temperatures, an organism would have more unsaturated fatty acids

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

effect of acyl chain length on membrane fluidity

A

shorter chains increase fluidity as they have fewer van der waals forces so are less tightly packed

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

effect of acyl chain saturation on membrane fluidity

A

Unsaturated fatty acids form kinks so cant pack closely together so increase fluidity

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

is the membrane symmetrical or asymmetrical

A

asymmetrical

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

why do hydrophobic molecules clump together

A

reduce SA:V in contact with water

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

lipid movement within membranes

A

Lateral diffusion
Flip-flop (not spontaneous)
Rotation
Flexion

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

how is membrane fluidity measured

A

FRAAP (fluorescence recovery after photobleaching)
protein of interest is labelled with a fluorescent marker, and the fluorescence in a small patch of membrane is then irreversibly “bleached” by a pulse of light from a focused laser. The time it takes for fluorescence to return to the bleached membrane patch provides a measure of how rapidly unbleached, fluorescently labelled proteins diffuse through the bilayer into the area. This “recovery” is plotted on a curve that shows fluorescence over time.

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

noncytosolic monolayer

A

phosphatidylcholine
sphingomyelin
Glycolipids
cholesterol (= to cytolsolic)

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

cytosolic monolayer

A

phosphatidylserine
phosphatidylethanolamine
phosphatidylinositols
cholesterol (= to non cytosolic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

types of membrane protein

A

Integral
Peripheral
Lipid-anchored

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Peripheral membrane proteins

A

Bind to surface by electrostatic interactions with the heads of lipids or other proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Lipid-linked membrane protein

A

lipid covalently attached to protein

17
Q

nonpolar aliphatic R groups

A

glycine
alanine
valine
leucine
methionine
isoleucine

18
Q

aromatic R groups

A

phenylalanine
tyrosine
tryptophan

19
Q

polar, uncharged R groups

A

serine
threonine
cysteine
proline
asparagine
glutamine

20
Q

charged R groups

A

lysine
arginine
histidine
aspartate
glutamate

21
Q

The polar nature of peptide bonds are not energetically favourable in the hydrophobic core of the lipid bilayer. How is this problem overcome

A

Hydrogen bonding between the partial negative charge in the carbonyl oxygen and the partial positive charge of the amide hydrogen in a regular pattern
Neutralises charges
Length of chain compressed due to the hydrogen bonding- alpha helix formation
This involves the backbone-not side groups

22
Q

beta barrel integral membrane protein

A

all carbonyl oxygens and amide hydrogens are also bonded in a regular pattern, but the hydrogen bonding patterns are further away. Tend to be found in mitochondrial outer membrane and bacterial outer membranes.

23
Q

helical bundle membrane proteins

A

the integral proteins that form alpha helices in the membrane

24
Q

antiparallel beta sheet

A

is formed with adjacent -strands running in opposite directions. Every other side chain extends above or below the sheet
Hydrogen bonding between strands

25
Q

dimensions of lipid bilayer

A

50 angstroms
30 of which are the hydrophobic region

26
Q

extended conformation, 1 residue=

A

3.5 angstrom

27
Q

alpha helical conformation, 1 residue=

A

1.5 angstrom
20 residues to span hydrophobic core

28
Q

hydrophobicity scale

A

negative=hydrophobic amino acid
Average hydrophobicity of a stretch of amino acids is calculated, plotted on graph
When window is over a hydrophobic stretch of amino acids there is a trough
troughs indicate transmembrane regions
Hydrophobicity analysis does not predict beta-barrel membrane proteins.

29
Q

how to remove integral membrane proteins from the lipid bilayer

A

detergents

30
Q

how to remove peripheral membrane proteins that are attached to protein

A

high salt concentrations

31
Q

protein channels structure-multipass transmembrane proteins

A

series of alpha helices that cross bilayer multiple times
hydrophilic side chains form an aqueous pore

Cell biology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions