Cytoskeleton and Organelles Flashcards Preview

Histology Exam 1 TonyFrim > Cytoskeleton and Organelles > Flashcards

Flashcards in Cytoskeleton and Organelles Deck (102):
1

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

Microtubules

2

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

Microfilaments

3

Intermediate filaments

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

4

Functions of cytoskeleton

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

5

Long cylinders composed of tubulin heterodimer of α and β tubulin

microtubules

6

All tubulin monomers bind ___

GTP

7

Which end of the polarized microtubules binds GTP

Plus end of microtubule binds GTP (promotes polymerization)

8

Hydrolyzed GDP at which end of microtubule

Minus end (favors dissociation)

9

Tubulin subunits form long rows called

protofilaments

10

How many protofilaments associate to form the tubule?

13 protofilaments

11

Half life averages of microtubules are around __ mins

10 minutes

12

Faster growing end of microtubule

Plus End

13

Basal bodies have what type of arrangement of microtubules

9 x 3 arrangement

14

Microtubules occur as ______ in cilia and ______ in basal bodies

doublets; triplets

15

More stable: microtubules or microfilaments

microfilaments

16

F-actin

Filamentous actin

17

G-actin

globular actin monomers

18

In microfilaments, one complete turn involves how many monomers

Fourteen

19

Microfilaments

helical actin filaments

20

Invagination of cell surface during cytokinesis

Cleavage furrow

21

Cleavage furrow provides contractile apparatus to "pinch off"

daughter cells

22

Stress fibers

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

23

Actin organized by

α-actinin, talin

24

Actins role in integrin adhesion

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

25

Adhesion belts

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

26

Lamellapodia

outward projections of cytoplasm the leading edge of migrating cells

27

Microvilli

Fingerlike extension at cell surface; Increases cell surface area

28

Where is membrane skeleton (spectrin) most prominent

erythrocytes (but spectrin is ubiquitous)

29

Sickle cell anemia involves modification of

spectrin skeleton

30

______ links spectrin to Band 3 and Glycophorin

Ankyrin

31

Intermediate filaments size relative to microfilaments and microtubules

"intermediate"

32

Assembly and disassembly of intermediate filaments are regulated by

phosphorylation of proteins

33

How many basic types of intermediate filaments

Six basic types

34

Rope-like polymers of long, fibrous protein

Intermediate filaments

35

One of the most common markers for neoplasia

Change in cytokeratin expression

36

Type I intermediate filament

acidic keratin

37

Type II intermediate filament

neutral to basic keratin

38

Type III intermediate filaments

vimentin, desmin, glial fibrillary acid protein, peripherin

39

Type IV intermediate filaments

neurofilaments (axons and dendrites)

40

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

Mitochodrion

41

Name of area between the outer and inner membranes of mitochondria

intermembrane space

42

Inner matrix compartment of mitochondria contain granules that bind...

(Mg +2 and Ca +2)

43

Matrix granules increase in number when

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

44

Mitochondrion matrix contains all the enzymes of the TCA cycle except

succinate dehydrogenase (located on the inner mitochondrial membrane)

45

Elementary particles contain

ATP synthase

46

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

ATP synthase

47

Mitochondria have their own genetic apparatus composed of

circular DNA, mRNA, tRNA, and rRNA

48

Most mitochondrial proteins are encoded by

nuclear DNA

49

Mitochondrial Energy Generation

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

50

ATP in mitochondrial energy generation is generated by

chemiosmotic coupling

51

Two types of Endoplasmic reticulum

Rough(granular ER) and smooth (agranular ER)

52

Endoplasmic reticulum is the site of

noncytosolic protein synthesis

53

The interior ER region is called the

cisterna (or lumen)

54

ER is abundant in cells synthesizing

secretory proteins

55

Phospholipids for new membranes are produced in

cytosolic half of ER

56

Where is cholesterol produced?

Endoplasmic reticulum

57

Ceramide is produced in the

ER

58

Many proteins in the ER have what sugars attached?

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

59

Irregular network of membrane-bound channels which lack ribosomes

Smooth ER

60

Where are smooth ER found in abundance?

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

61

Golgi complex consist of

several stacks of disk-shaped cisternae(saccules)

62

Describe cisternae of Golgi

slightly curved, with flat centers and dilated rims

63

Major functions of Golgi Apparatus (5)

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

Cis (entry) face of Golgi

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

Medial compartment of Golgi

comprises a few cisterna lying between cis and trans faces

66

Trans (exit) face of Golgi

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

67

Trans golgi network

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

68

microbodies

membrane-bound ovoid organells

69

Functions of peroxisomes in human liver

• 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

Disease caused by defective peroxisome assembly

Zellweger syndrome

71

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

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

72

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

vesicle coating proteins

73

Transport vesicles are coated with either

clathrin or coating protein (COP)

74

COP coated vesicles transport between

rER ans Golgi (and various Golgi stacks)

75

Clathrin mediates transport of

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

76

Lysosomes

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

77

Lysosomes contain

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

78

Lysosome membrane contains proton pump for...

acidifying the lysosome interior

79

Tubulovesicular structures formed by endocytosis from plasma membrane

endosome

80

Endosomes usually fuse with

lysosomes

81

Early endosomes

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

82

Late endosomes

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

83

Cell drinking via small vesicles

pinocytosis

84

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

constitutive process

85

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

phagocytosis

86

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

Macrophages

87

Phagocytosis may or may not involve

cell-surface receptors

88

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

Heterophagy

89

Digestion of endocytosed ligands may occur in

multivesicular bodies

90

Digestion of phagocytosed microorganisms and foreign particles may be completed in

phagolysosomes

91

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

Autophagy

92

Receptor-mediated endocytosis

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

93

Process of ligands being endocytosed

(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

3 possible fates for ligand in RME

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

95

non-coated pit that has a cholesterol binding protein

caveolin

96

cholera and tetanus utilize a _______ _______ pathway

clathrin independent

97

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

exocytosis

98

Regulated secretion (exocytosis)

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

99

Constitutive secretion (exocytosis)

"continuous" release of material without any storage step or extracellular signal

100

In immune cells, exosomes carry molecules needed for

adaptive immune response

101

Exosomes can be captured by other cells and

transfer info to another cell

102

Where are exosomes formed?

Multivesicular bodies/ endosomes