Brainscape's Knowledge GenomeTM

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


See full index

ANAT 212 > Lecture 7 > Flashcards

Lecture 7 Flashcards

1
Q

name proteasome subunits

A

20s core
19s regulator - cap

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

describe 20s core of proteasome

A

2 outer rings of 7 similar alpha subunits - interact with gap
2 inner rings of 7 similar beta subunits
3 of beta subunits = have protease activity on inside surface - 6 proteins cut into aas
19s cap attaches to outer ring

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

describe 19s cap of proteasome

A

base with AAA-family ATPase subunits
protein unfoldase = unfolds to primary structure, line of aas goes into core
lid with nonatpase subunits = polyub receptors, dubs (cut and recycle ubs)
one up and one down

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

what is AAA

A

family of atp dependent proteins with many diff functions

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

describe ub receptor function

A

increase efficiency of targetting
select only k48 chains - lysines
recognizes poly ub if on lysine 48
protect adjacent premature DUB activity = reversible

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

name 2 types of ub receptors

A

intrinsic receptors
extrinsic receptors

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

describe intrinsic ub receptors

A

cap subunits = rpn10 and rpn13 bind poly ub

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

describe extrinsic ub receptors

A

shuttling ub receptors
separate from proteasome
bind poly ub through ub associated domain = UBA = proteasome must be close by, but not efficient so brings close to proteasome to be degraded
have ub like domain = UBL that is recognized by cap

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

describe proteasome cap = parts

A

ub receptor rpn13 and 10 = recognize tail and then attach to cap
base has AAA atpases = unfold and gets into core
unfoldase Rpt 1-6
lid
core
DUB rpn 8/11

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

describe cap functions - binding

A

lid ub receptors bind poly ub or ubl domains of shuttling receptors
dubs remove ub chains
base unfoldase passes substrate into core

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

describe proteasome core

A

cavity inside core
small and narrow
proteins have to stay unfolded
2 active subunits in each beta ring, 6 sites total with protease activity
one cuts at basic aa, one at acidic aa, one at hydrophobic aas
peptides diffused out and are digested into aas by peptidases = cuts into aas but if polypeptide = degraded by peptidases in cytosol

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

name step 1 of proteasome function

A

19s cap recognizes poly ub or ubl domain of shuttling receptor

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

name step 2 of proteasome function

A

dubs remove poly ub from substrate and pass it to base

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

name step 3 of proteasome function

A

base subunits use atpase activity to unfold substrate and feed it inside 20 s core

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

name step 4 of proteasome function

A

proteolytic beta subunits cleave substrate into short peptides or aas

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

describe ub proteasome summary - 8 steps

A

1 - Ub is activated by E1 and transferred to E2 on Cys side chains
2- E3 selects substrate polypeptide and transfers Ub from E2 to Lys side chains in the substrate
3- E2/E3 attaches more Ub onto Lys48 of the previous Ub, to make poly- Ub chain
4 - Poly-Ub is bound by shuttling receptor with UBL domain
5- 19s cap lid binds poly-Ub, or UBL domain of shuttling receptor
6- DUB removes poly-Ub
7 -19s base ATPase unfolds substrate
8 - Proteasome core cleaves at basic, acidic and hydrophobic sites

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

describe the cell - cytosol

A

soup
all reactions happen in cytosol - part pf cytoplasm

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

describe the cell - PM

A

allows cells to communicate to exterior and receive signals from interior
regulation of what gets in and out = vesicles and communications
proteins inserted in pm = not cytosolic proteins
Integrated into memebranes

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

describe the cell - secretory pathway

A

made in ER - proteins = transferred to golgi, modified and secreted to pm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

describe the cell - endocytic pathway

A

take components form outside cell
vesicles fused by lysosome
isolated in cytosol by membranes = components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

is a cell empty

A

hell NAH
very crowded
transport must be regulated or would be hard

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

describe secretory pathway

A

a transport system between several types of organelles and the cell surface (Plasma Membrane)
synthesis of proteins, lipids at the endoplasmic reticulum (ER)
traffic through Golgi, to the plasma membrane (PM)
internalization through endosomes, to degradation in lysosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

are all organelles connected to secretory pathway

A

nooooo not all organelles
ex - mito

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

describe lumen

A

interior of secretory organelles = continuous with each other and extracellular space
vesicles bud from one organellar membrane and fuse with another without releasing contents into cytosol
lumenal environment (salts, ph, protein, cofactors) = similar to extracellular space (plasma) BUT DIFF from cytosol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is main diff between cytosol and lumen (extracellular)

A

cytosol = reducing environment, no disulfide cysteine bonds
ER = oxidizing so losing electrons, disulfide bonds between cysteine here

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

name 4 important functions of biological membranes

A

provide enclosure to cells and to organelles within cells - like doors, regulate in and out
allow regulated transport of materials between compartments
provides sites within cells for biochemical reactions - can favour certain ones
supports contacts with environment outside cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

describe important function of biological membranes - provide sites

A

Photosynthesis, oxidative phosphorylation
metabolism of biological molecules = lipids, glycans, others

28
Q

describe important function of biological membranes - supports contacts

A

cell motion, recognition of other cells, cell fusion = with exterior, like fibroblasts
transmission of signals from exterior to interior of cells

29
Q

describe properties of membranes

A

form hydrophobic barriers between aq compartments (hydrophilic) within cell - cytosol and organellar lumens
flexible and can be formed into diff shapes

30
Q

what are membranes selectively permeable to

A

small hydrophobic molecules
not to charged/polar molecules and big hydrophobic

31
Q

what controls the movement of impermeable molecules across membrane

A

specialized protein complexes control movement of impermeable molecules across membranes

32
Q

how do membranes store energy

A

as concentration gradients - mainly happens in mitochondria
voltage - nerve cells
ph, potassium, sodium, calcium gradients

33
Q

describe model of membranes

A

fluid mosaic model = membranes made of lipid molecules and membrane proteins
lipids organized in bilayer = sheet that is polar on each side and hydrophobic in middle
hydrophobicity acts as a barrier to water soluble molecules
membrane proteins can rotate and diffuse laterally in fluid bilayer

34
Q

can phospholipids flip

A

noooooo
moves laterally or opens and closes

35
Q

name major membrane lipids

A

phospholipids - in all membranes
glycolipids = only at pm (not in er or golgi)
cholesterol = preferentially located in pm
other types with special functions

36
Q

what do all membrane lipids have

A

hydrophobic sections - interior

37
Q

what determines physical properties of membrane

A

lipid composition
mobility = diffusion, rotation
curvature, thickness

38
Q

can lipids flip

A

YAAAA
regulated by proteins
lipid in membrane can flip from one layer to next but proteins in membrane CANNOT

39
Q

describe phospholipids - abundance

A

most abundant lipids

40
Q

name phospholipids parts

A

polar head groups
2 fatty acid tails

41
Q

describe polar head groups of phospholipids

A

choline or other charged group
phosphate and glycerol
classification by head groups

42
Q

describe fatty acid tails groups of phospholipids

A

Hydrophobic
diff lengths
saturated = no double bonds, all single covalent bonds
unsaturated = 1 or more double bonds = forms kink in trail
found in many diff combos with head groups

43
Q

name phospholipid head groups

A

PC = phosphatidyl choline
PE = phosphatidyl ethanolamine
PS = phosphatidyl serine
most common
sphingomyelin = SM = not glycerol lipid but related

44
Q

which phospholipid head group is not abundant

A

PI = phosphatidyl inositol
can be phosphorylated and act as signalling molecules

45
Q

what affects lipid mobility

A

head group size and charge

46
Q

describe phosphatidyl ethanolamine

A

glycerol forms ester linkage with fatty acid tail = 3rd carbon binds phosphate and phosphate binds polar group

47
Q

describe phosphatidyl serine

A

has neg charge
usually faces cytosol

48
Q

describe phosphatidyl choline

A

Attached to choline

49
Q

describe sphingomyelin

A

has choline in polar head
bit diff
amide linkage to fatty acid tail

50
Q

describe phosphatidyl-inositol

A

other type of lipid
sugar
oh can be phosphorylated
regulatory molecule
faces cytosol

51
Q

describe fatty acid tails

A

2 of them
hydrocarbon chain of 14-24 carbons
varying number of double bonds
Saturated tails = straighter and more flexible = if long = membrane thicker, determines which proteins will be integrated
double bonds introduce bends in tail = reduce flexibility and length, has kink
types of tails in membrane determine thickness and fluidity
AMPHIPATHIC - polar head groups

52
Q

describe unsaturated fatty acid tails

A

cis double bond = less flexible
H’s in same plane
not as large
kink so shorter
increases fluidity of membrane

53
Q

describe saturated fatty acid tails

A

longer

54
Q

describe glycolipids

A

only found on outside surface of pm = always faces exterior of cell
head groups contain diff sugar groups in many combos = important for cell contacts with environment and other cells
sugar = glucose, galactose or nanosugar
ceramide = also basis of SM (sphingomyelin) and the 3 sugars = galactosecerebroside, ganglioside, sialic acid

55
Q

describe cholesterol

A

structurally diff from other lipids

56
Q

why is cholesterol rigid

A

steroid ring structure
lateral mobility, rotation much lower
reduces mobility pf surrounding phospholipids, makes fatty acid tails more rigid

57
Q

describe cholesterol structure

A

amphipathic
hydrophobic fatty acid tail (hydrophobic interaction = straight so thicker) and polar head group
integrated between lipids of membrane = provide rigidity, reduces lateral movements and rotations

58
Q

describe membrane symmetry

A

many biological membranes are asymmetric = lipid composition on each side is diff
asymmetry of pm is important for function
exterior has glycolipids
interior has stronger neg charge - high PS levels = transmits signals
asymmetry is not absolute but actively maintained

59
Q

describe inner and outer leaflet of membrane

A

outer = pc, sm, glycolipids
inner = pe, ps, pc, low amount of pi
(signalling) = molecules that transmit signals, has sugar and oh group = can be phosphorylated

60
Q

describe organelle lipids

A

lipid composition is diff between organelles, depends on biological requirements
other specialized lipids found in diff membranes

61
Q

describe main components of PM, ER and mito

A

PM = highest cholesterol, and SM
ER & mito = higher levels of PC and PE

62
Q

what are microdomains

A

regions of membrane that are organized laterally = sideways, in patches - diff from rest of membrane

63
Q

where are lipid rafts located

A

PM and trans-golgi = have special domains called lipid rafts

64
Q

describe lipid rafts

A

thicker than surrounding membrane - rich in cholesterol
lipids with longer tails cluster together in rafts

65
Q

what does cholesterol do - lipid rafts

A

cholesterol binding straightens lipid tails, causing thicker membrane = many cholesterols so v thick = 12-14 carbons, fatty acid trails may get together to make lipid rafts
diff protein content and biological function

66
Q

describe why microdomains are important

A

some proteins that regulate communication of cell to exterior = only integrated in these microdomains = diff from other membrane parts bc how thick they are

67
Q

what does glycerol do - fatty acids

A

link between polar head and 2 fatty acid tails

ANAT 212 (34 decks)

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