Final review 3

Question 1

What is the site of controlled ubiquination called?

Answer 1

degron

Question 2

What are degrons controlled by?

Answer 2

Phosphorylation

Question 3

What is the phase known as “point of no return”?

Answer 3

S phase

Question 4

What is highly precise when copying DNA?

Answer 4

DNA polymerase

Question 5

Explain okazaki fragments

Answer 5

at the lagging strand DNA polymerase synthesize DNA fragment by a back stitching mechanism

Question 6

What provides starting primer for DNA polymerase?

Answer 6

Primase

Question 7

What helps extend the template to the 3’ end of the DNA?

Answer 7

Telomerase

Question 8

What are histones?

Answer 8

help package genome

Question 9

What ties together the sister chromatids?

Answer 9

cohesion

Question 10

What initiates microtubule formation?

Answer 10

centrosome

Question 11

What is the microtubule system that forms between the two centrosomes

Answer 11

spindle

Question 12

The ends of the microtubules attach to what of the sister chromatids?

Answer 12

kinetochores

Question 13

How are the chromosomes pulled by the centrosome?

Answer 13

By microtubule shortening

Question 14

Describe microtubule disassembly

Answer 14

microtubules disassemble at the kinetochores which moves a system of sliding rings towards the centrosome

Question 15

What is DNA damage checkpoint initiated by?

Answer 15

p53

Question 16

Why is p53 known as a Tumor Suppresor gene?

Answer 16

because a mutation to the p53 gene can cause increase in cancer

Question 17

Germ cells vs stomatic

Answer 17

germ cells are gametes
stomatic cells are the rest of the organism

Question 18

What is apoptosis?

Answer 18

programed cell death

Question 19

what is Necrosis?

Answer 19

Bursting of cell due to damage, causes inflamation

Question 20

What morphology changes occurs during apoptosis?

Answer 20

Chromatin compaction, condensation of cytoplasm, the break of the nuclear envelope, nuclear fragmentation, blebbing, cell fragmentation

Question 21

How is DNA fragmentation obeserved?

Answer 21

Agarose gel electrophoresis

Question 22

What occurs during DNA fragmentation during apoptosis?

Answer 22

Apoptosis activates nucleases that cleave off DNA

Question 23

Where do the nucleases cut the DNA?

Answer 23

Between the nucleosomes

Question 24

What is apoptosis executed by?

Answer 24

Caspases

Question 25

How is apoptosis activated from inside the cell? (intrinsic pathway)

Answer 25

cytochrome C

Question 26

Explain apoptosis from outside the cell (extrinsic pathway)

Answer 26

The killer lymphocyte with a Fas ligand comes to the target cell and connect to the Fas death receptor

Question 27

What are villi?

Answer 27

specialized epithelial areas of the gut that function in the absorption of nutrients

Question 28

Why must villi cells be constantly replaced?

Answer 28

because of the high turnover rate

Question 29

In the intestine, new cells are produced, where and by what?

Answer 29

bottom of the crypt by a set of stem cells

Question 30

What directly links the cytoplasm of neighboring cells?

Answer 30

gap junctions

Question 31

What forms a strong physical connection between cells?

Answer 31

Desmosomes

Question 32

What forms the extracellular matrix?

Answer 32

proteins and polysaccharide

Question 33

Regulatory steps of a protein in order

Answer 33

DNA, RNA transcript, mRNA in nucleus, mRNA in cytosol, protein, degraded protein

Question 34

What are transcription factors?

Answer 34

DNA binding proteins that regulate transcription initiation

Question 35

Homeodomains form what type of bonds?

Answer 35

Hydrogen bonds with nucleobases

Question 36

What is a transcription activator?

Answer 36

DNA binding protein that increases transcription of a gene

Question 37

What is a transcription Repressor ?

Answer 37

DNA binding protein that decreases transcription of a gene

Question 38

What is an enhancer?

Answer 38

DNA sequence that is recognized by a transcription activator

Question 39

What is a silencer?

Answer 39

DNA sequence that is recognized by a transcription repressor

Question 40

What occurs during DNA methylation?

Answer 40

suppresses gene expression by attracting transcription reppresors

Question 41

What are the characteristics of cell-surface receptors?

Answer 41

signaling molecule are hydrophilic and requires signal transduction mechanism

Question 42

What are intracellular receptor characteristics?

Answer 42

signal is a hydrophobic molecule and binds directly to the intracellular receptor which often acts as a transcriptional regulator

Question 43

Nuclear hormone receptors are regulated by what

Answer 43

ligand-regulated transcription factors.

Question 44

What is the signal transduction pathway?

Answer 44

- rapid relay of extracellular signal to the intracellular target - amplification of the signal - modulation of signal - integration of different signals

Question 45

Relaying signal by:

Answer 45

- protein phosphorylation - GTP-binding proteins - protein-protein interaction - second messenger molecules such as cAMP, Calcium, IP3

Question 46

GPCRs have how many transmembrane domains?

Answer 46

7 domains

Question 47

The activated GPCR acts as what?

Answer 47

GEF

Question 48

What is a messenger in cell signaling?

Answer 48

Ca2+

Question 49

Why does Ca2 have a large affect on the cell?

Answer 49

Naturally Ca2+ levels are low so when raised cell is not adjusted

Question 50

What is caused by fertilization of an egg by a sperm?

Answer 50

Calcium influx resulting a response in plasma membrane that blocks a second fertilization