Telomerase and s

Quiescent cells are in what pahse of the cell cycle?

G0

Where is G0 located?

an offshoot og G1

Are cells still metabolically active in G0

Yes

Are cells still dividing in G0

NO

Is G0 a permanent state of the cell cycle?

No

Primary stimulation

lack of nutrition and growth factors

are adult stem cells capable of regenerating tissue?

Yes

Are adult stem cells inherently active?

NO

Are Hepatocytes metabolically active? Where are they located?

Yes; liver

Do hepatocytes divide?

No

What type of tissue comprises fibroblasts?

active connective tissue cells

When do fibroblasts become mitotically active?

injury/inflammation

What do fibroblasts do?

repair

Cells that are permanently arrested somewhere in the cell cycle are known as.,,

senescent

Are senescent cells metabolically active? Can they divide?

Yes, no

Once cells are in senescence, can they ever get out?

NO, they are arrested

What stimulates senescence?

aging and DNA damage

What are examples of senesence?

replicative, stress-induced, post mitotic

What is permanent growth arrest of terminally differentiated cell types (e.g., neurons, myocytes, adipocytes, etc.)

post-mitotic senescence

What type of senescence is limited replicative potential of normal cells due to telomere attrition or dysfunction

replicative senescence

What is another name for premature senescence (before telomeres shorten) due to various stressors (e.g., oxidative damage, DNA damage, oncogene activation, etc.)

stress-induced senescence

when there is a lack of nutrition, ________ will occur

quiescence

where there is cell stress,___________ will occur

senescence

What is a big deciding factor regarding cell growth/proliferation?

mTOR

Telomeres(TTAGGG) are associated with what type of senecencee?

replicative

Shelterin is what

protein complex bound to telomeric repeats

What is the purpose of telomere loops?

ensure that telomere ends are not exposed and are protected from premature degradation

By how much do telomeres shorten with each division?

50-200 bp

What is the mitotic clock?

process where after telomeres are short enough that the cell stops dividing

TRF2 (telomere binding factor 2) is involved in what?

senescence

POT1 (protection of telomeres 1) is involved in

apoptosis

cell lines that have entered the crisis phase will undergo ______ whereas those that survivie will become ____________

crisis, immortalized

Telomerase is what type of enzyme? what does it do?

reverse transcriptase? elongate chromosomes

DNA polymer that uses internal RNA as a primer

TERT

RNA template for synthesis of new telomere DNA

TERC

do most cancer cells have telomerase?

yes

Where is TERT located?

5p

The upstream promotor of TERT is rich in…

CpGs

normal somatic cells are ___________ whereas methylated cells __________

unmethylated, methylated

If there are too many pro-proliferative transcirpiton factors for the promotor of TERT, this may cause…

TERT to activate

C228T and C250T are what?

promotor mutations