Brainscape's Knowledge GenomeTM

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


See full index

bio > intercellular compartments > Flashcards

intercellular compartments Flashcards

1
Q

List some of the different intercellular compartments:

A

nucleus, ER (smooth and rough), golgi apparatus, plasma membrane, lysosome, endosome.

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

How are organelles constructed?

A

Daughter cell inherits organelles from its mother during cell division.

Many organelles enlarge and are distributed to two daughter cells during division

Proteins targeted to correct organelle, due to Inheritance of important translocators in the cell membranes of these organelles

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

Describe nucleus evolution *

A

membranes that surround nucleus are continuous with some of the ER.
Plasma membrane of cells invaded into cell to surround region of DNA and form nucleus.
Nuclear environment is similar to cytosol.
ER lumen came from plasma membrane pinching in to look like extracellular environment.

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

How did mitochondria evolve?

A

Endosymbiosis where mitochondria evolved from an ancient cyanobacterium which has been engulfed by an early eukaryotic mitochondriate ancestor.

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

What are the steps of transport between compartments?

A
  1. Gated transport - from nucleus to cytosol
  2. Protein translocation through membrane transport, occurs between cytoplasm and mitochondria and cytoplasm and ER
  3. Vesicular Transport - ER to Golgi to Endosome, lysosome or plasma membrane via constitutive and regulated secretory pathway.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are signal sequences and signal peptidases?

A
  • Signal sequences are a Protein sorting signal that specifies a particular destination in the cell
  • can also be multiple internal sequences that form a 3D signal patch.
  • Signal peptidases are enzymes that removes a signal when sorting is complete.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How are signal sequences tested?

A

The ER signal sequence is removed from ER protein and attached to a cytosolic protein.

Can also be removed or mutated

Nuclear localization signals can be mutated

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

Describe nuclear structure.

A

Nucleus is enclosed by nuclear envelope that consists of outer membrane continuous with ER and inner membrane.

Nuclear pore complexes are used for transport in and out.

Perinuclear space continuous with ER

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

How do molecules diffuse through nuclear pore complex?

A

Small molecules diffuse through NPC, large molecules use signal sequence and receptors for transport, but usually transported in folded state.

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

What is a nuclear localization signal?

A

It is recognized by nuclear import receptors (importins) and not cleaved after transport.

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

What are the steps of nuclear import?

A
  1. Protein binds to receptor, moves through nuclear pore complex to nucleus.
  2. Ran-GTP binds to receptor, changes shape of Nuclear Import Receptor to make it release cargo protein.
  3. In cytosol, GTP is hydrolyzed, RAN-GDP dissociates from receptor, helps NIR bind another nuclear protein.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do Ran-GAP and Ran-GEF do?

A

Regulators of RAN Function, Results in compartmentalization of Ran-GTP and Ran-GDP

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

How to GEF and GAP function?

A

GEF causes release of GDP so GTP can bind.

GAP induces hydrolysis of GTP to GDP.

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

Describe steps of nuclear export

A
  1. Protein binds to export receptor using Ran-GTP, which keeps cargo bound to receptor.
  2. Protein moves to cytosol.
  3. Ran GTP converted to Ran GDP, cargo is released to cytosol.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe mitochondrial protein import:

A

Has to be imported in unfolded state.
Signal sequence or matrix proteins is an amphiphilic alpha helix that is recognized by receptors.

includes positive amino acids on one side and hydrophobic on the other.

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

Describe TOM Complex

A

TOM Complex - moves proteins across outer mitochondrial membrane into intermembrane space or outer mitochondrial membrane (all proteins going to the mitochondria from cytoplasm pass through this complex.

17
Q

Describe tim 22/23 complexes

A

23 -inner part, move proteins from intermembrane space into matrix or the inner mitochondrial membrane (single transmembrane domain)

22- inner part: moves proteins from intermembrane space into inner mitochondrial membrane (multiple transmembrane domains)

18
Q

describe oxa complex

A

inner part: moves proteins from matrix into the inner mitochondrial membrane (origin: made in the matrix or transported to the matrix).

19
Q

Describe Sam complex

A

outer part, moves beta barrel proteins from intermembrane space into outer mitochondrial membrane

20
Q

Describe the signal sequence for import into nucleus.

A

Consists of lysines and arginines.

21
Q

Describe rough er

A

Membrane bound ribosomes, functions in lipid and protein biosynthesis.

22
Q

Describe smooth er.

A

functions in hormone synthesis, detox in liver, intracellular ca2+ storage, no ribosomes, functions in vesicle transport to golgi

23
Q

How does protein translocation occur

A

co or post translational import into the ER in unfolded state.

24
Q

What has to happen for the protein to translocate to the ER?

A

SRP (signal recognition particle) recognizes signal sequence to direct ribosome to ER.

25
Q

how does translocation of soluble proteins occur?

A

Binding of start transfer results in opening of the translocator and movement of protein into the ER lumen

Signal peptidase then cleaves signal sequence.

26
Q

How does translocation of a single pass transmembrane protein occur?

A

Stop Transfer Sequence anchors the protein in the membrane and changes conformation of translocator to release protein laterally into membrane

27
Q

Describe transmembrane proteins with an internal signal sequence.

A

Orientation favors most positively charged amino acids in the cytosol

Internal sequences aren’t cleaved off

28
Q

Describe multipass transmembrane proteins -

A

includes hydrophobic start and stop transfer sequences.

29
Q

How is number of peaks related to number of transmembrane domains?

A

They are equal.

30
Q

What modifications occur in the ER?

A

Disulfide bond formation, n-linked oligosaccharide added to Asn in ER lumen.

31
Q

Describe Unfolded protein Response

A

Increases transcription of genes that encode chaperone proteins, which is caused by activation of gene regulatory proteins (transcription factors)

32
Q

What are the different sensors for misfolded proteins?

A

IRE1, PERK, ATF6

33
Q

How does ATF6 function?

A

ATF6 undergoes cleavage event (proteolysis) and releases portion of protein which becomes a transcription factor.

34
Q

How does IRE1 function?

A

Regulates splicing of mrna causing transcription of regulatory gene.

35
Q

How does lipid bilayer synthesis occur?

A

Phospholipid synthesis occurs in the cytosolic leaflet of the ER membrane.

Translocators move
lipids between
leaflets of the
membrane.

36
Q

How does PERK function?

A

It phosphorylates, inactivating translation initiation factor, reducing proteins that enter ER. There is selective translation of gene reg. protein.

bio (23 decks)

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