test4

Question 1

Enables proteins to bind to phosphotyrosines

Answer 1

SH2 or PTB domains

Question 2

Enables proteins to bind proline-rich regions of proteins

Answer 2

golgi

Question 3

The activity of the Sos protein

Answer 3

Ras-GEF

Question 4

Constitutive Ras activity is associated with

Answer 4

cancer

Question 5

associated with the inner nuclear membrane

Answer 5

intermediate filaments (lamins)

Question 6

found at the cell cortex and within microvilli

Answer 6

actin filaments

Question 7

the contractile ring is made of this

Answer 7

actin (and myosin)

Question 8

forms actin bundles that can associate with myosin II

Answer 8

alpha-actinin

Question 9

binds individual actin subunits, preventing assembly

Answer 9

thymosin

Question 10

prevents actin:myosin cross-bridging

Answer 10

tropomyosin

Question 11

nucleates new actin fiber formation on the side of existing fibers

Answer 11

Arp2/3 complex

Question 12

binds individual subunits and speeds elongation

Answer 12

profilin

Question 13

What does kinesin-13 do

Answer 13

it is a catastrophe factor that destabilizes microtubules

Question 14

associate with the growing plus ends of microtubules

Answer 14

+Tips

Question 15

What is the function of stathmin?

Answer 15

binds pairs of microtubule dimers, preventing polymerization

Question 16

Associates with the minus ends and is found at the MTOC

Answer 16

gamma-TuRC

Question 17

What nucleotide to tubulin proteins bind and what happens when it is hydrolyzed

Answer 17

alpha and beta bind GTP:GDP if beta tubulin binds GDP, the protofilaments/microtubules become less stable

Question 18

What fluorescent dye is typically used for cell cycle analysis by flow cytometry (a DNA histogram)

Answer 18

Propidium iodide (PI)

Question 19

Cyclin-Cdk complexes G-Cdk, G/S-Cdk, S-Cdk, and M-Cdk go with what cyclins and Cdk partners?

Answer 19

G-Cdk - Cyclin D ; Cdk4, Cdk6
G/S-Cdk - Cyclin E ; Cdk2
S-Cdk - Cyclin A ; Cdk2, Cdk1
M-Cdk - Cyclin B ; Cdk1

Question 20

Mitogens signaling via Ras activate a

Answer 20

MAP kinase cascade

Question 21

Which transcription factor stimulates delayed-response gene expression

Answer 21

Myc

Question 22

How is Rb inactivated?

Answer 22

by phosphorylation

Question 23

What might excessive mitogen signaling lead to?

Answer 23

Myc and p53-dependent cell cycle arrest or apoptosis

Question 24

DNA double strand breaks activate which kinase?

Answer 24

ATM

Question 25

UV-induced DNA damage induces which kinase?

Answer 25

ATR

Question 26

How do Chk1/Chk2 destabilize the p53:Mdm2 complex?

Answer 26

phosphorylation of p53

Question 27

How does p53 activation lead to cell cycle arrest?

Answer 27

Expression of the CKI, p21

Question 28

What negative feedback mechanism regulates p53 levels?

Answer 28

p53 can transactivate the Mdm2 gene, leading to p53 oscillations in response to persistent DNA double strand breaks

Question 29

cells responding to signaling factors they secrete themselves

Answer 29

autocrine signaling

Question 30

different types of intercellular signaling

Answer 30

contact dependent, paracrine, synaptic, endocrine

Question 31

positive feedback can generate

Answer 31

all or none responses

Question 32

What are some cell surface receptors?

Answer 32

ion channel coupled receptors, G protein coupled receptors, enzyme coupled receptors

Question 33

What are some intracellular receptors?

Answer 33

preformed signaling complex on a scaffold protein assembly of signaling complex on an activated receptor assembly of signaling complex on phosphoinositide docking

Question 34

intracellular signaling proteins can act as molecular switches by?

Answer 34

GTP binding or phosphorylation

Question 35

What are some mechanisms of receptor desensitization

Answer 35

``` receptor down regulation receptor inactivation receptor sequestrination inactivation of signaling protein production of inhibitory protein ```

Question 36

How do G proteins work

Answer 36

ligands binding to GPCR activate G proteins

Question 37

cAMP activates which enzyme?

Answer 37

PKA

Question 38

What binding domain enables proteins to bind to phosphoinositides?

Answer 38

PH

Question 39

How are RTKs activated?

Answer 39

by signaling proteins that cause dimerization and trans-autophosphorylation of RTKs

Question 40

What are MAPK cascades?

Answer 40

central signaling pathways that regulates a wide variety of cellular processes

Question 41

The PI 3 kinase pathway promotes what

Answer 41

cell survival and growth

Question 42

What transmits info from extracellular chemical signals to the nucleus resulting in DNA transcription and expression of genes

Answer 42

JAK/STAT signaling

Question 43

What happens in interphase?

Answer 43

cell grows and makes a copy of its DNA

Question 44

What happens in M phase?

Answer 44

cell separates DNA into 2 sets and divides cytoplasm

Question 45

What are the major control steps of the cell cycle?

Answer 45

start transition, G2/M, metaphase to anaphase

Question 46

Activation of Cdk requires what?

Answer 46

a CAK - Cdk activating kinase

Question 47

How is Cdk activity regulated?

Answer 47

by inhibitory phosphorylation and cyclin level changes

Question 48

what are the phases of mitosis?

Answer 48

prophase metaphase anaphase telophase

Question 49

what are the 3 types of microtubules?

Answer 49

astral kinetochore interpolar

Question 50

major motor proteins of mitotic spindle

Answer 50

kinesins and dyneins

Question 51

cohesins do what

Answer 51

regulate separation of sister chromatids

Question 52

cytokinesis is driven by

Answer 52

an actin contractile ring containing myosin II

Question 53

3 major types of cytoskeletal protein filaments

Answer 53

actin, microtubules, intermediate filaments

Question 54

nucleation is what in the formation of cytoskeletal polymers

Answer 54

rate limiting step

Question 55

critical concentration is

Answer 55

when steady state phase is reached

Question 56

toxins that affect actin filaments

Answer 56

actin and tubulin

Question 57

listeria moves by

Answer 57

polymerizing actin

Question 58

smooth muscle does not express

Answer 58

troponin

Question 59

microtubules are formed

Answer 59

by the polymerization of a dimer of 2 globular proteins

Question 60

tubulin forms

Answer 60

microtubulin

Question 61

which end of microtubules is more dynamic

Answer 61

positive end

Question 62

rescue phase= | catastrophe phase=

Answer 62

growth phase | shrinking

Question 63

kinesin moves to | dyneins move to

Answer 63

kinesins move to plus end dyneins move to minus end

Question 64

cell projection is a

Answer 64

cell protrusion