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Flashcards in FInal 4 Deck (101):
1

Provide mechanical strength in cells

IF

2

Used for cell locomition and cell surface shape

Actin

3

Determine position of organelles and direct movement

MTs

4

Specialized structures that increase absorptive surface area in epithelial cells

Microvilli

5

What kind of cytoskeletal material are nuclear lamina made from?

IFs

6

Cytoskeletal material used for flagella

MTs

7

Birthplace of all cytoplasmic MTs

MTOC

8

What are MTs protofilaments?

Polymers of alpha-beta tubulin heterodimers

9

Which subunit of MT does not cleave GTP to GDP?

Alpha

10

How many MT protofilaments assemble to form a tube?

13

11

What do actin monomers bind?

ATP

12

How many actin protofilaments intertwine to form a fiber?

2

13

What do two monomers of IFs form?

Coiled-coil dimer

14

What do two coiled-coil dimers of IFs form?

Staggered tetramer in an antiparallel arrangement

15

How many protofilaments of IFs twist into a ropelike filament?

8

16

What is the rate-limiting step for actin filament assembly?

Nucleation

17

What is the nucleation process of filament assembly dependent upon?

Concentration

18

Free actin and tubulin monomers are bound by what?

NTP

19

What happens when a GTP cap is lost?

MT will fray and shrink

20

Name for when MTs shrink due to loss of GTP cap

Catastrophe

21

MTs regrowing after a catastrophe

Rescue

22

What does taxol do to MTs?

Stabilizes them, essentailly killing rapidly dividing cells

23

Complex responsible for initiating MTs

gamma-TuRC

24

What end of MTs are inside MTOC

Negative

25

Complex responsible for initiating actin arrays

Arp2/3

26

Where do Arp2/3 usually nucleate?

PM

27

What angle do Arp2/3 bind to sides of existing actin filaments to form branches?

70

28

2 actin monomer binding proteins

Thymosin, profilin

29

Actin filament destabilizing protein

cofilin

30

Actin filament severing protein

Gelsolin

31

2 actin filament capping proteins

CapZ, tropomodulin

32

MT binding protein

Stathmin

33

MT filament binding protein

MAPs

34

2 MT filament destabilizer

Catasrophin, katanin

35

Actin-based motor

Mysoin

36

MT-based plus-end directed motor

Kinsein

37

MT-based negative-end directed motor

Dynein

38

WHat happens when myosin is treated with trypsin?

Heads and a small piece of tail are released from the tail

39

What happens when myosin is treated with papain?

Splits the heads up and removes the tail

40

Which myosin moves towards the minus end?

Mysoin Vi

41

What is the fastest motor protein?

Dynein

42

Which motor protein "walks"

Kinesin

43

While ____ binds tightly with bound NTP, ____ binds tightly without NTP

Kinesin, mysoin

44

One dimensional finger-like projection of actin

Filopodia

45

Two dimensional sheet-like structure of actin

Lamellipodia

46

Three dimenisional projections used for phagocytosis

Pseudopodia

47

3 extracellular stimuli receiving g-proteins that actin cytoskeleton responds to

Rho, Rac, Cdc42

48

Produces large numbers of actin stress fibers

Rho

49

Yields large numbers of filopodia

Cdc42

50

Generates very large lamellapodia that encircles the cell

Rac

51

How long is S-phase

10-12

52

Comittment to undergo another round of cell division

Start point (G1)

53

Key part of prophase

Chromsomes condense

54

Key part of prometaphase

Breakdown of nuclear envelope

55

Key part of metaphase

Chromosomes aligned at equator

56

Key part of anaphase

Chromosomes are being pulled apart

57

Key part of telophase

Chrosomes are at the poles

58

How is centrisome duplication triggered?

G1/S-Cdk complex

59

MTs that radiate in all directions

Astral MTs

60

Attach end-on to kinetochore

Kinetochore MTs

61

Span distance between bipolar spindle

Overlap MTs

62

Push overlap MTs against each other

Kinesin-5

63

PUll spindles towards each other

Kinesin-14

64

Attach chromosomes to MTs for positioning

Kinesin-4, Kinesin-14

65

Attach astral MTs to periphery and pull spindles apart

Dyneins

66

3 forces that move chromosomes on the spindle

Kinetochore generated poleward force, poleward MT flux, polar ejection force

67

What force is Anaphase A defined by?

Kinetochore generated poleward force and MT flux

68

What force is Anaphase B defined by?

SPindle poles move apart, dynein pulling on astral MTs

69

Visible pucker in PM during cytokinesis

Cleavage furrow

70

How do cleavage furrows form?

Contraction along actomyosin contractile ring

71

Region between future duaghter cells

Midbody

72

What is the organization and deposition of contractile ring regulated by?

RhoA

73

WHat kind of proteins are cyclin dependent kinases?

Serine/threonine kinases

74

4 classes of cyclins

G1/S, S, M, G1

75

Bind to Cdks at the end of G1 and commit the cell to DNA replication

G1/S cyclin

76

Bind to Cdks during S-phase and are required for the initiation of DNA replication

S-cyclin

77

Promote events of mitosis and G2/M transition

M-cyclins

78

Promote the passage through "start" point by helping govern G1/S cyclins

G1-Cyclins

79

2 steps of Cdk activation

Cyclin binding alters conformation of T-loop, CAK phosphorylates a threonine residue within T-loop

80

Inhibitory protein of Cdk

Wee1

81

Inhibitory protein of Wee1

Cdc25

82

General family of inhibitor proteins of Cyclin-Cdk

CKI (Cdk inhibitor)

83

Responsible for initiating S-phase by destruction of G1-Ss cyclins and CKIs

SCF

84

Responsible for initiating M-phase by destruction of M cyclins and regulators

APC/c

85

3 enzymes that function in series for attachment of ubiquitin

E1, E2, E3

86

What activates APC/C?

Cdc20

87

Initiate DNA replication once per cycle and ensures that every base of DNA is faithfully replicated once

S-Cdks

88

Where does DNA replication begin?

ORF

89

COmplex of initiator proteins that assembles on ORF during late mitosis

pre-RC

90

WHat does preRC mature into?

Preinitiation complex

91

What mediates preinitiation complex?

S-Cdks

92

First two molecules nucleates by ORC complex

Cdc6, Cdt1

93

What does S-cdk phosphorylate to allow replication machinery to work?

Cdc6

94

How is Cdt1 bound until it is liberated by S-Cdk

Geminin

95

What is geminin destoryed by?

APC/C

96

What are duplicated chromosomes held together by?

Cohesin

97

When triggers entry into mitosis?

Accumulation of M-cyclins

98

Phosphatase that removes the brakes on the regulatory factors stopping M-Cdk

Cdc25

99

What triggers siter-chromatid separation?

APC/C

100

Protein that uses negative feedback to block APC/C from initiating sister-chromatid separation

Mad2

101

How does the exit of mitosis occur?

Inactivation of M-cdk activity by APC/C degradation