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Histology Exam 1 TonyFrim > Cytoskeleton and Organelles > Flashcards

Cytoskeleton and Organelles Flashcards

1
Q

Rigid, hollow cylinders of tubulin. Organized into curvy structures that radiate from MTOC

A

Microtubules

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2
Q

Flexible, contractile filaments of actin. Organized into linear bundles beneath plasma membrane

A

Microfilaments

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3
Q

Intermediate filaments

A

Ropelike fibers of keratin, lamina, or vimentin. Provide mechanical strength and carry stresses

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4
Q

Functions of cytoskeleton

A

maintain cell shape; stabilize cell adhesion and placement; facilitate movement(organelle motility/ chromosome separation/cilia and flagella-Microtubules)(muscle contraction/cell migration-Actin)

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5
Q

Long cylinders composed of tubulin heterodimer of α and β tubulin

A

microtubules

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6
Q

All tubulin monomers bind ___

A

GTP

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7
Q

Which end of the polarized microtubules binds GTP

A

Plus end of microtubule binds GTP (promotes polymerization)

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8
Q

Hydrolyzed GDP at which end of microtubule

A

Minus end (favors dissociation)

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9
Q

Tubulin subunits form long rows called

A

protofilaments

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10
Q

How many protofilaments associate to form the tubule?

A

13 protofilaments

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11
Q

Half life averages of microtubules are around __ mins

A

10 minutes

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12
Q

Faster growing end of microtubule

A

Plus End

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13
Q

Basal bodies have what type of arrangement of microtubules

A

9 x 3 arrangement

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14
Q

Microtubules occur as ______ in cilia and ______ in basal bodies

A

doublets; triplets

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15
Q

More stable: microtubules or microfilaments

A

microfilaments

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16
Q

F-actin

A

Filamentous actin

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17
Q

G-actin

A

globular actin monomers

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18
Q

In microfilaments, one complete turn involves how many monomers

A

Fourteen

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19
Q

Microfilaments

A

helical actin filaments

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20
Q

Invagination of cell surface during cytokinesis

A

Cleavage furrow

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21
Q

Cleavage furrow provides contractile apparatus to “pinch off”

A

daughter cells

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22
Q

Stress fibers

A

Actin bundles along basal cell surface terminate at focal adhesions; stabilize integrin adhesions

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23
Q

Actin organized by

A

α-actinin, talin

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24
Q

Actins role in integrin adhesion

A

Provide tension for migration and adhesion; provide scaffold for intracellular signal transduction

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25
Q

Adhesion belts

A

Circumferential actin near apical cell surface
– Stabilize cadherin-mediated adherens junctions
• Organized by catenins, -actinin - Provide scaffold for intracellular
signal transduction

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26
Q

Lamellapodia

A

outward projections of cytoplasm the leading edge of migrating cells

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27
Q

Microvilli

A

Fingerlike extension at cell surface; Increases cell surface area

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28
Q

Where is membrane skeleton (spectrin) most prominent

A

erythrocytes (but spectrin is ubiquitous)

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29
Q

Sickle cell anemia involves modification of

A

spectrin skeleton

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30
Q

______ links spectrin to Band 3 and Glycophorin

A

Ankyrin

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31
Q

Intermediate filaments size relative to microfilaments and microtubules

A

“intermediate”

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32
Q

Assembly and disassembly of intermediate filaments are regulated by

A

phosphorylation of proteins

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33
Q

How many basic types of intermediate filaments

A

Six basic types

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34
Q

Rope-like polymers of long, fibrous protein

A

Intermediate filaments

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35
Q

One of the most common markers for neoplasia

A

Change in cytokeratin expression

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36
Q

Type I intermediate filament

A

acidic keratin

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37
Q

Type II intermediate filament

A

neutral to basic keratin

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38
Q

Type III intermediate filaments

A

vimentin, desmin, glial fibrillary acid protein, peripherin

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39
Q

Type IV intermediate filaments

A

neurofilaments (axons and dendrites)

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40
Q

Rod shaped organelles- have an outer bounding membrane and inner membrane that invaginated to form cristae

A

Mitochodrion

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41
Q

Name of area between the outer and inner membranes of mitochondria

A

intermembrane space

42
Q

Inner matrix compartment of mitochondria contain granules that bind…

A

(Mg +2 and Ca +2)

43
Q

Matrix granules increase in number when

A

cations increase in cytoplasm. (may help regulate cytosolic ion concentration)

44
Q

Mitochondrion matrix contains all the enzymes of the TCA cycle except

A

succinate dehydrogenase (located on the inner mitochondrial membrane)

45
Q

Elementary particles contain

A

ATP synthase

46
Q

enzyme involved in coupling oxidation to phosphorylation of ADP to form ATP

A

ATP synthase

47
Q

Mitochondria have their own genetic apparatus composed of

A

circular DNA, mRNA, tRNA, and rRNA

48
Q

Most mitochondrial proteins are encoded by

A

nuclear DNA

49
Q

Mitochondrial Energy Generation

A

Energy produced by oxidation of fatty acids, glucose, and amino acids using Krebs cycle

50
Q

ATP in mitochondrial energy generation is generated by

A

chemiosmotic coupling

51
Q

Two types of Endoplasmic reticulum

A

Rough(granular ER) and smooth (agranular ER)

52
Q

Endoplasmic reticulum is the site of

A

noncytosolic protein synthesis

53
Q

The interior ER region is called the

A

cisterna (or lumen)

54
Q

ER is abundant in cells synthesizing

A

secretory proteins

55
Q

Phospholipids for new membranes are produced in

A

cytosolic half of ER

56
Q

Where is cholesterol produced?

A

Endoplasmic reticulum

57
Q

Ceramide is produced in the

A

ER

58
Q

Many proteins in the ER have what sugars attached?

A

N-linked (Asn) oligosaccarides . (further modified in the Golgi)

59
Q

Irregular network of membrane-bound channels which lack ribosomes

A

Smooth ER

60
Q

Where are smooth ER found in abundance?

A

Steroid synthesizing cells and cells involved in synthesis of triglycerides and cholesterol

61
Q

Golgi complex consist of

A

several stacks of disk-shaped cisternae(saccules)

62
Q

Describe cisternae of Golgi

A

slightly curved, with flat centers and dilated rims

63
Q

Major functions of Golgi Apparatus (5)

A

1)modify N-oligosaccharides on Asparagine 2)distribute non-cytosolic proteins to plasma membrane, lysosomes, and secretory vesicles 3)assembles proteoglycans from proteoglycan core proteins 4)adds mannose 6-phosphate to proteins that are targeted for lysosomes 5) sulfates sugars on proteoglycans

64
Q

Cis (entry) face of Golgi

A

consists of cis Golgi network and cis cisterna and is the forming cisternae, located at the side of the stack facing the rER, and associated small transfer vesicles

65
Q

Medial compartment of Golgi

A

comprises a few cisterna lying between cis and trans faces

66
Q

Trans (exit) face of Golgi

A

comprises the maturing cisternae, which are located at the side of the stack facing vacuoles and secretory granules

67
Q

Trans golgi network

A

lies apart from the last cistern at the trans face and is separated from the golgi stack

68
Q

microbodies

A

membrane-bound ovoid organells

69
Q

Functions of peroxisomes in human liver

A
  • Breakdown (by oxidation) of excess fatty acids.
  • Breakdown of hydrogen peroxide (H2O2), by-product of fatty-acid oxidation. Catalyzed by the enzyme catalase.
  • Participates in cholesterol synthesis. One of the enzymes involved, HMG-CoA reductase, is the target of cholesterol-lowering “statins”.
  • Participates in the synthesis of bile acids.
  • Participates in the synthesis of the lipids used to make myelin.
  • Breakdown of excess purines (AMP, GMP) to uric acid.
70
Q

Disease caused by defective peroxisome assembly

A

Zellweger syndrome

71
Q

nonliving components of the cell that do not possess metabolic activity and are not bounded by membranes.

A

inclusions(pigments, lipid, crystalline, storage and secretory granules, glycogen)

72
Q

The formation and transport of vesicles within a cell is aided by

A

vesicle coating proteins

73
Q

Transport vesicles are coated with either

A

clathrin or coating protein (COP)

74
Q

COP coated vesicles transport between

A

rER ans Golgi (and various Golgi stacks)

75
Q

Clathrin mediates transport of

A

vesicles from the trans-golgi network and from the plasma membrane

76
Q

Lysosomes

A

dense, membrane bound organelles of heterogeneous morphology. Primary=storage; Secondary=engaged in degradative process

77
Q

Lysosomes contain

A

acid hydrolyses to degrade proteins, nucleic acids, oligosaccharides and phospholipids

78
Q

Lysosome membrane contains proton pump for…

A

acidifying the lysosome interior

79
Q

Tubulovesicular structures formed by endocytosis from plasma membrane

A

endosome

80
Q

Endosomes usually fuse with

A

lysosomes

81
Q

Early endosomes

A

more electron lucent; may fuse with other vesicles to form CURL(compartment of uncoupling of receptor and ligand)

82
Q

Late endosomes

A

more electron dense interior; more acidic pH (5.5); develop via fusion with lysosomes or endosomal “maturation”

83
Q

Cell drinking via small vesicles

A

pinocytosis

84
Q

Pinocytosis is a part of normal cell activities and not a triggered process therefore it is a _________ process

A

constitutive process

85
Q

Uptake of microorganisms, cells, and foreign particles by a cell into a phagosome

A

phagocytosis

86
Q

Some cells specialized for phagocytosis (degrade proteins and cellular debris)

A

Macrophages

87
Q

Phagocytosis may or may not involve

A

cell-surface receptors

88
Q

Ingestion and degradation of foreign material taken into cell by receptor mediated endocytosis or phagocytosis

A

Heterophagy

89
Q

Digestion of endocytosed ligands may occur in

A

multivesicular bodies

90
Q

Digestion of phagocytosed microorganisms and foreign particles may be completed in

A

phagolysosomes

91
Q

Segregation of an organelle or other cell component within membranes from the rER to form an autophagic vacuole (autophagosome).

A

Autophagy

92
Q

Receptor-mediated endocytosis

A

specific uptake of a substance (e.g., low-density lipoproteins, EGF) by a cell with plasma-membrane receptors for that substance (ligand).

93
Q

Process of ligands being endocytosed

A

(1) Ligand binds to receptor (2). Membrane invagination and endosome formation (3). Proton pump acidifies endosomal compartment (4) Endosome moves along microtubule tracks towards trans Golgi reticulum (TGR).(5) Interaction with TGR determines fate of ligand and receptor.

94
Q

3 possible fates for ligand in RME

A
  • Ligand degraded in lysosome and receptor recycled (LDL)
  • Ligand and receptor recycled (transferrin)
  • Ligand and receptor both degraded in lysosomes (Epidermal growth factor)
95
Q

non-coated pit that has a cholesterol binding protein

A

caveolin

96
Q

cholera and tetanus utilize a _______ _______ pathway

A

clathrin independent

97
Q

Release of cell material by secretory granule membrane fusion with the plasma membrane

A

exocytosis

98
Q

Regulated secretion (exocytosis)

A

Release of proteins and other materials stored in the cell in response to an extracellular signal

99
Q

Constitutive secretion (exocytosis)

A

“continuous” release of material without any storage step or extracellular signal

100
Q

In immune cells, exosomes carry molecules needed for

A

adaptive immune response

101
Q

Exosomes can be captured by other cells and

A

transfer info to another cell

102
Q

Where are exosomes formed?

A

Multivesicular bodies/ endosomes

Histology Exam 1 TonyFrim (8 decks)

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