Test 2 Ch. 15 And Ch. 9

Front 1

Order Liver, Hair cells, and Intestinal cells by frequency of cell division

Back 1

Most Frequent: Intestinal

Infrequent: Liver Cells

Never divide: Hair cells

Front 2

What is the product of a stem cell division?

Back 2

When a stem cell divides it makes 1 differentiable cell + a new stem cell

Front 3

What are the 3 checkpoints in internphase?

Back 3

G1, S, and G2

Front 4

Most of a cells life is spent in what phase of the cell cycle?

Back 4

Interphase

Front 5

During what stage of interphase does most growth occur?

Back 5

G1

Front 6

What is the purpose of G2 checkpoint?

Back 6

To check if S phase went properly and to check if we're ready for M phase

Front 7

The cell cycle starts after ____ phase

Back 7

After M phase

Front 8

What are the 3 pathways possible after the restriction point?

Back 8

1) Halt cell cycle and go to G0

2) Try to fix the damage

3) If we can't fix the damage --> Apoptosis

Front 9

What is the point of no return where a cell is committed to the cycle?

Back 9

G1 checkpoint

Front 10

What if the the cell fails to pass the G1 checkpoint?

Back 10

It goes back to G0

Front 11

When is the start of organelle replication?

Back 11

Start after restriction point

Front 12

during what stage of the cell cycle is the most cell growth observed

Back 12

G1

Front 13

What is the Rb protein?

Back 13

Retinoblastoma protein is a tumor suppressor protein

Front 14

The Rb protein is the major protein in the __ checkpoint

Back 14

G1

Front 15

Rb is tightly bound to the ___ transcription factor

Back 15

E2F

Front 16

What happens to the Rb protein after the G1 restriction point?

Back 16

The Rb protein gets hyperphosphorylated and dissociates from the E2F transcription factor

Front 17

How does Rb act as a tumor suppresor?

Back 17

Hyperphosphorylation only occurs after the restriction point which frees up the E2F TF for transcription of products needed for S phase. Thus it prevents premature transcription of E2F products

Front 18

Growth factors induce a transition from __ to __ phase

Back 18

G0 --> G1

Front 19

What cyclin is responsible for the hyperphosphorylation of Rb?

Back 19

Cyclin D binds to CDK4, then CDK6, then CDK2 which each phosphorylate Rb

Front 20

When is the ONLY stage in the cell cycle where a cell is sensitive to growth factors?

Back 20

G1

Front 21

What is the longest phase of the cell cycle?

Back 21

G1 Phase

Front 22

What is the second longest phase in the cell cycle and how long does it last?

Back 22

S phase lasts 9 hours

Front 23

What is the second shortest phase of the cell cycle and how long does it last?

Back 23

G2 lasts 4 hours

Front 24

What is the shortest phase in the cell cycle and how long does it last?

Back 24

M phase lasts 1 hour

Front 25

What is the difference between a chromosome and chromatid?

Back 25

2 chromatids = 1 chromosome

Front 26

When are chromatids produced?

Back 26

S phase

Front 27

What cyclin and CDK partners are involved in the mid-G1 phase-CDK complex?

Back 27

Cyclin D with CDK4 and CDK6

Front 28

What cyclin and CDK partners are involved in the late-G1/S phase-CDK complex?

Back 28

Cyclin E with CDK 2

Front 29

What cyclin and CDK partners are involved in the S phase-CDK complex?

Back 29

Cyclin A with CDK 2 and CDK 1

Front 30

What cyclin and CDK partners are involved in the M phase-CDK complex?

Back 30

Cyclin B with CDK 1

Front 31

Concentration of cyclins ____ while concentration of CDK _____

Back 31

Cyclin cycle but CDK's are constant

Front 32

What proteins are capable of pausing the cell cycle and in what stage would this be most effective?

Back 32

Cyclin-CDK inhibitors and most inhibition occurs at G1/S

Front 33

What is the role of ATP in an inactive Cyclin-CDK Complex?

Back 33

The ATP provides an inorganic phosphate to the partly active cyclin-cdk complex to further expose the T-loop and to fully activate the complex

Front 34

What's so important about the T loop?

Back 34

T-loop exposure is necessary for catalytic activity and further exposure of the T-loop is essential in complete activation

Front 35

Inhibition of the Cdk-activating Kinase (CAK) results in?

Back 35

This slows the cell cycle but doesn't halt it since the Cyclin-CDK complex is partially functional

Inhibition would prevent further exposure of the T-loop and phosphorylation of the T-loop

Front 36

What's the purpose of ubiquitin-protein ligases

Back 36

Tag for degradation to the proteosome in an effort to prevent retrograde movement through the cell cycle

Front 37

SCF and APC have the same purpose. How do they achieve this in terms of their relation to E1 and E2 and what is this purpose?

Back 37

SCF/APC bind to a protein and ligates the E1-activated Ub that was transported by E2 to tag it for destruction

Front 38

SCF doesn't degrade which cyclin

Back 38

Cyclin B is not degraded by SCF

Front 39

What is the function of each of the 3 components of the ubiquitin degradation system

Back 39

E1 = Ubiquitin activating enzyme = Activates ubiquitin

E2 = Ubiquitin-conjugating enzyme = Transfer Ub from E1 -- > E3

E3 = Ubiquitin Protein Ligase = Ligases the poly ub chain

Front 40

What are the 3 components of the SCF trimer complex?

Back 40

Skp - Cullin - F-box

Front 41

____ protein is critical is stabilizing components of the internal transport system and it's strands form tangles inside neurons of Alzheimer sufferers

Back 41

Tau!

Front 42

What signals E1 to activate Ub?

Back 42

Phosphorylation of Serine, Threonine, and Tyrosine

Front 43

SCF acts mostly in ____ phase by ____ inhibitors involved in cell cycle arrest at the ___ phase?

Back 43

G1/S, degrading, G1

Front 44

What are the 2 ubiquitin-protein ligases (E3) critical to the cell cycle?

Back 44

SCF and Anaphase-promoting complex

Front 45

What is unique about how SCF recognizes a substrate compared to APC/C?

Back 45

SCF recognizes a phosphorylated protein rather that a specific AA sequence

Front 46

What is the structure of APC/C?

Back 46

It is a apoenzyme until bound by Cdc20

Front 47

What is the function of Wee1 Kinase? Where is Wee1 kinase mostly active?

Back 47

To add an inhibitory phosphate in order to pause the cell cycle until repairs can be completed

It is mostly active in G2 and closer to mitosis

Front 48

How is Wee1 kinase's action reversed?

Back 48

Cdc25 phosphatase

Front 49

Binding of a growth factor stimulates production of which cyclin?

Back 49

Cyclin D

Front 50

What is the order in which cyclins are produced and degraded?

Back 50

Cyclin D --> Cyclin E --> Cyclin A --> Cyclin B

Front 51

What is the maturation-promoting factors aka what is M cyclin?

Back 51

Cyclin B + Cdk1 and Cdk2

Front 52

What lamins are found in the nuclear pore and which are not?

Back 52

A and C are intermediate structures found in the nuclear pore and B is in the nucleoplasmin

Front 53

What would lead to less lamin B?

Back 53

DNA replication + ageing

Front 54

What cyclin-cdk complex is responsible for degradation and reformation of the nuclear envelope?

Back 54

M cyclin-Cdk1 complex

Front 55

How does the APC aid in promoting anaphase?

Back 55

APC tags and destroys cyclin B between metaphase and anaphase which allows reformation of nuclear envelope

Front 56

How does the APC aid in separation of sister chromatids?

Back 56

APC tags securin which consequently releases separin

Front 57

What is the function of separin?

Back 57

It cleaves condensin and cohesin

Front 58

APC won't degrade cyclin ___ until the spindle fiber checkpoint has ensured that all fibers are attached and tensed

Back 58

Cyclin B!

Front 59

how does helicase separate DNA?

Back 59

Heicase breaks AT bonds which are weaker and the consequential destabalization leads to breaking of the GC bonds

Front 60

What is responsible for relieving stress and then ligating during DNA replication?

Back 60

Topoisomerase/Gyrase

Front 61

Why do we need a primase?

Back 61

Polymerase cannot make DNA denovo so we need a primer which is supplied by primase

Front 62

How is rapid weight loss a symptom of cancer?

Back 62

Cancer is #1 usage of ATP due to the constant energy needed for divisions

Front 63

How accurate is DNA preservation after proofreading?

Back 63

1 mutation/ 1 billion bases

Front 64

What is SSBP?

Back 64

Single Strand Binding Protein

Front 65

Why do we write 5' --> 3'?

Back 65

We use the 5' triphosphates to couple the formation of a phosphodiester with the 3' hydroxyl

Front 66

What is unique about the replication bubbles of eukaryotes?

Back 66

Eukaryotes use ultipe origins to replicate the chromosome. These bubbles then merge

Front 67

What molecule is responsible for fusing 2 adjacent bases in DNA?

Back 67

DNA Ligase

Front 68

Why does more sunlight lead to elevated mood?

Back 68

In the absense of light, seratonin is degraded to melatonin, thus depleting this hormone

Front 69

What direction does exonuclease (proof-reading) activity write?

Back 69

3' --> 5'

Front 70

If DNA Pol I can remove primer and replace it with DNA, why do we need DNA Pol III?

Back 70

DNA Pol I can only produce short strands due to a missing "clamp" that DNA Pol III has

Front 71

What activates the 3' --> 5' exonuclease activity?

Back 71

An unpaired base due to the kink that it will introduce to the DNA which has a constant width which destabilizes Pol exposing the exonuclease core

Front 72

What is the function of DNA Pol II

Back 72

Fix mutations

Front 73

What's different between the proof reading ability of DNA Pol I and DNA Pol II

Back 73

DNA Pol I ONLY takes care of replication mistakes, not mutations

Front 74

What does the RNA Primase provide that is necessary for extension?

Back 74

It provides an -OH at the 3'

Front 75

Who has a longer primer, E. Coli or eukaryotes?

Back 75

Eukaryotes are ~35 nucleotides total while E. Coli is 2-5 nucleotides

Front 76

What enables the SSBP to do their job?

Back 76

SSBP's have a higher affinity for ssDNA than dsDNA

Front 77

What is the role of Mg2+ in the Pol complex?

Back 77

Mg2+ increases the nucleophilicity of 3' Oxygen

Front 78

The __' end is always shortened after replication

Back 78

5 and this is the telomere region that we lose due to a inability to write over where the primer was

Front 79

HIgher methylation levels are observed in telomerase gene promoter regions of _____ cell types

Back 79

Differentiated

Front 80

Accumulation of ____ leads to shortnened telomeres due the compounds _____ and an insufficient amount of ____ to metabolize the compound

Back 80

Acetyl Aldehyde, cytotoxicity, ADH2 enzyme

Front 81

Fructose gets uptaken faster than glucose due to passive channels in the gut. How does this lead to oxidative stress?

Back 81

Fructose gets degraded to glucose when its needed or to triglycerides when we dont It's the accumulation of triglycerides that is bad because they're easily oxidizable.

Front 82

Why did Carol Geider get a Nobel prize in 2009?

Back 82

She figured out that telomeres shorten progressively in telomerase-null mice which led to shorter lifespans

Front 83

How can we prevent amyloid fibril aggregation in terms of tubulin?

Back 83

Irreversibly bind GTP to beta tubulin to prevent catastrophe

Front 84

What element of the SCF allows for specificity of binding?

Back 84

F-box

Front 85

What ultimately dictates the exit of mitosis?

Back 85

Proteolysis

Front 86

What would be the effect of improper spindle fiber attachment on APC?

Back 86

It would inhibit CDC20-APC complex

Front 87

How is lamin effected in progeria?

Back 87

A mutated lamin will retain it's fernesyl anchor and form a deformed nuclear membrane --> Apoptosis

Front 88

Define Semi-conservative replication

Back 88

Each daughter DNA contains 1 parental strand

Front 89

Polymerase can only replicate while reading __ --> __ and can only synthesize __ --> __

Back 89

Reading 3' --> 5'

Synthesize 5' --> 3'

Front 90

How does Zovirax prevent Herpes Simplex replication?

Back 90

Inhibits Helicase-Primase complex