Brainscape's Knowledge GenomeTM

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


See full index

Cell Lecture > Exam 3 - Ch 12 through Ch 15 > Flashcards

Exam 3 - Ch 12 through Ch 15 Flashcards

1
Q

components of the endomembrane system

A

ER
Golgi apparatus
Endosomes
Lysosomes

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

endoplasmic reticulum

A

continuous network of flattened sacs and cisternae filled with lumen

roughER + smoothER

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

what are cisternae

A

tubules of the ER

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

function of the rough ER

A

site of protein synthesis

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

functions of the smooth ER

A

drug detox, carb metabolism, calcium storage, steroid synthesis

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

function of the golgi apparatus

A

processing and sorting of proteins

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

function of endosomes

A

carry material brought into cell

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

function of lysosomes

A

digestion of material

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

where are ribosomes held on the rER

A

on the cytosolic side by receptor proteins

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

signal peptide sequence

A

determines the fate of protein transportation

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

what events happen for a protein that enters the lumen of the rER

A
  1. signal recognition particle (SRP) recognizes and binds to signal peptide sequence and the SRP receptor on the ER membrane
  2. Pore opens with energy from GTP
  3. Signal peptide sequence is cleaved by signal peptidase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the different forms that integral membrane proteins can have (3)

A
  1. bulk outside due to stop-transfer sequences
  2. bulk inside due to start-transfer sequences
  3. even due to alternating stop and start transfer sequences
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the different pathways of post-translational import

A
  1. into ER lumen
  2. into mitochondria/chloroplast membranes
  3. into mitochondria/chloroplast matrix/stroma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what do chaperone proteins do

A

associated with protein synthesis in the cytosol to keep it unfolded and then pulling the polypeptide into the ER lumen and folding them

also do so for the chloroplasts/mitochondria

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

where are most of the proteins used in the mitochondria/chloroplasts coded

A

nuclear genes

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

when are polypeptides known to be sent to mitochondria and chloroplasts

A

when they are synthesized on free ribosomes and have a transit sequence

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

what does transit peptidase do

A

cleave the transit sequence once its threaded through the pore of the mitochondria/chloroplast

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

how do chaperone proteins fold the polypeptides once in the lumen/matrix/stroma

A

by binding to the hydrophobic regions of the polypeptide and folding them internally

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

what is ER-associated degradation

A

when improperly folded or modified proteins are exported from the ER and degraded in the cytosol by proteasomes

the proteasomes look for the ubiquitin tag to know what to degrade

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

ER stress

A

When too many unfolded/mid folded proteins accumulate

There are diseases associated with this

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

What is a cell’s response to ER stress

A

Destroying the proteins

Trying to refold the proteins

Commit apoptosis

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

Where is smooth ER that focuses on drug detox and carbohydrate metabolism

A

In hepatocytes

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

Where is smooth ER that focuses on calcium storage

A

Muscle cells

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

How does the smooth ER detox drugs

A

Enzymes perform hydroxylation

This makes the molecule more soluble

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

How does the smooth ER breakdown glycogen stores

A
  1. Glycosidic bonds broken
  2. Glucose phosphorylation
  3. Phosphate removed by glucose-6-phosphatase
  4. Glucose leaves via GLUT2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How does the ER play a role in biosynthesis of membranes

A

Phospholipids from the ER are moved by phospholipid exchange proteins to other membrane organelles and the plasma membrane

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

What is the Golgi apparatus composed of

A

Cisternae are stacked disk-shaped sacs of flattened membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the two sides of the golgi

A
  1. Cis-golgi network: toward the ER side receives vesicles from the ER
  2. Trans-golgi network: away from ER side and where vesicles leave
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

movement through the golgi (two ways)

A
  1. stationary cisternae model: vesicles move between each cisternae as they remain stationary
  2. cisternal maturation model: cisternae move themselves from CGN toward TGN
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Glycosylation

A

starts in the ER and finished in Golgi

  1. N-linked glycosylation: add oligosaccharide to the nitrogen on the terminal amino group of asparagine residues
  2. O-linked glycosylation: add oligosaccharide to the oxygen on the hydroxyl group of serine or threonine residues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

KDEL sequence

A

protein tag that keeps soluble proteins in the ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what does mannose-6-phosphate do in protein trafficking

A

send proteins to lysosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Secretory pathways (3)

A
  1. Constitutive
  2. Regulated
  3. Polarized
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

constitutive secretion definition and example

A

when secretory vesicles move directly from TGN to plasma membrane; continuous and unregulated

mucous secretion in intestines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

regulated secretion

A

when secretory vesicles accumulate in cell before fusing w/plasma membrane; need extracellular signal to fuse and release contents

insulin

36
Q

polarized secretion

A

secretory vesicles release proteins only on one side of the cell

nerve cells and their neurotransmitters

37
Q

signaling in exocytosis

A
  1. specific extracellular signal binds to cell surface receptor
  2. second messenger released (usually Ca2+)
  3. [second messenger] signals regulated secretion
38
Q

receptor-mediated endocytosis

A

ligand/receptor interaction

39
Q

phagocytosis

A

ingestion of large particles, microorganisms, or cells

40
Q

pinocytosis

A

internalization of external fluid

maintains SA/volume ratio

41
Q

what are coated vesicles

A

vesicles with protein coats on the cytosolic side

helps to determine location

42
Q

examples of coated vesicles

A

clathrin-coated: from TGN to endosomes

COPI-coated: from golgi back to ER

COPII-coated: from ER to golgi

caveolin-coated: unknown, may be involved w/cholesterol uptake

43
Q

what are lysosomes

A

activated endosomes than contain digestive enzymes capable of degrading all macromolecules

44
Q

how do lysosomes form

A

enzymes are fused into endosomes until they can no longer fuse, and the pH drops, then activating lysosome

45
Q

lysosome function

A

to degrade foreign material brought into cell by phagocytosis and receptor-mediated endocytosis; soluble materials are released into cytosol; insoluble materials remain in lysosome = residual bodies (CELLULAR AGING)

breakdown of damaged/unneeded cellular parts

extracellular digestion (release of enzymes to the outside of the cell)

46
Q

macrophagy

A

when an entire organelle is broken down by lysosome

47
Q

microphagy

A

when cytoplasmic molecules are broken down by lysosome

48
Q

lysosomal storage disease

A

when lysosomes lack a functional enzyme to breakdown a particular substance, so that substance accumulates

diagnosed prenatally

49
Q

vacuole location

A

in plant cells

50
Q

provacuole is analogous to _____

vacuole formation is analogous to ______

A

endosome

lysosome formation

51
Q

vacuole functions

A

store hydrolytic enzymes

maintain turgor pressure

regulate cytosolic pH

protein storage

malate storage (CAM plants)

anthocyanin storage (flower color)

toxin storage

52
Q

peroxisomes

A

contain catalase that degrade hydrogen peroxide and release water

not derived from ER

53
Q

what is the cytoskeleton

A

a network of interconnected filaments and tubules that extends throughout the cytosol

increases internal organization and maintains cell shapes

54
Q

functions of the cytoskeleton

A 
cell movement
cell division
organelle and mRNA movement
cell signaling
cell to cell adhesion
55
Q

what are the elements of the cytoskeleton and their relative size

A

microtubules, intermediate filaments, and microfilaments

from biggest to smallest

56
Q

what are the subunits for microtubules

A

alpha and beta tubulin heterodimers

57
Q

what are the subunits for intermediate filaments

A

occur as single filaments or any bundles

58
Q

what are the subunits for microfilaments

A

actin monomers

59
Q

function of microtubules

A

moving components within cells or moving fluid outside of cells

60
Q

types of microtubules

A

cytoplasmic (inside cell)

axonemal (outside cell)

61
Q

examples of cytoplasmic microtubules

A

nerve cell axons
spindle fibers

“interstate system”

62
Q

examples of axonemal microtubules

A

cilia
flagella
basal bodies

63
Q

what is microtubule structure

A

long, hollow cylinders w/outer wall of 13 protofilaments

doublets (2 microtubules) are found in cilia and flagella

triplets (3 microtubules) are found in basal bodies and centrioles

64
Q

how are microtubules formed

A

nucleation + elongation

alpha and beta tubulin dimers are formed and then joined together to form alternating rings

all dimers face same direction, giving polarity

dimers add to positive end more often

65
Q

where do microtubules originate

A

at the microtubule-organizing center (MTOC)

66
Q

microtubules-associated proteins (MAPs)

A

bind along microtubules so it may interact with other cellular structures

ex: Tau protein in axons

67
Q

+ - TIP proteins

A

stabilize the + end of the microtubule to decrease the likelihood of disassembly

68
Q

catastrophins

A

promote microtubule disassembly

69
Q

functions of microfilaments

A

muscle contraction
cell migration
maintain cell shape
produce cleavage furrow during cell division

70
Q

microfilament structure

A

globular (single actins) has ATP

filamentous (helical strands of globular actin) has ADP

71
Q

types of actin

A

muscle-specific (alpha actin)

nonmuscle-specific (beta and gamma actins)

72
Q

actin-binding proteins

A
  1. thymosin beta-4: binds the free ATP of G-actin
  2. formin promotes the addition of G-actin
  3. gelsolin breaks up microfilaments
  4. capz prevents + elongation
  5. filamin splices crisscrossed filaments so they may connect
  6. actinin stabilizes ordered arrays
73
Q

what are microvilli

A

microfilaments that line intestinal cells to increase SA for digestion and absorption

74
Q

function of intermediate filaments

A

to provide structure and allow for tension in animal cells

75
Q

examples of intermediate filaments

A

keratin in epithelial cells
vimentin in connective tissue
desmin in muscle cells

76
Q

intermediate filaments are usually how many protofilaments

A

8

77
Q

plectin proteins

A

help connect the 3 cytoskeleton elements

78
Q

what are the three levels of movement

A

tissue level, cellular level, and intracellular level

79
Q

what is tissue level movement

A

cells in muscle tissue contracting

ex: bending limbs, beating heart, uterine contractions

80
Q

what is cellular level movement

A

motility of one or a few cells

ex: cilia, flagella, amoeboid movement, cancer invasion, actin dependent migration

81
Q

what is intracellular level movement

A

components within the cell need to be shuttled

ex: chromosome separation during anaphase, RNA movement, vesicles moving

82
Q

how are microtubule interactions mediated

A

by kinesins and dyneins

83
Q

how are microfilament interactions mediated

A

by myosins

84
Q

what are kinesins and dyneins

A

microtubule-associated motor proteins that “walk” along the microtubule

kinesins move toward + end
dyneins move toward - end

85
Q

how do kinesins move

A

leading globular head binds to ATP

other globular head swings forward and binds

Cell Lecture (8 decks)

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