Final review 2

Question 1

Actin filament/microtubule structure

Answer 1

twisted two stranded 8-9nm diameter

Question 2

Microtubule structure?

Answer 2

Hollow tubes 24nm diameter

Question 3

Intermediate filament structure?

Answer 3

rope-like structure, 10nm diameter

Question 4

What is G-actin?

Answer 4

globular, monomeric actin

Question 5

What is F actin?

Answer 5

filamentous actin polymer

Question 6

What is a thin flexible filament that is highly dynamic?

Answer 6

F - actin

Question 7

What end is the ATP binding site?

Answer 7

Minus end

Question 8

What are sequestering proteins responsible for?

Answer 8

Important to maintain a high concentration of monomeric actin in the cell

Question 9

What are the three responsibilities of actin networks?

Answer 9

Shape cells, move cells, and divide cells

Question 10

What are myosin motors?

Answer 10

Force-generating ATPases that walk along actin cables

Question 11

What is a tubulin subunit made of?

Answer 11

a and b tubulin

Question 12

What tubulin binds tightly to GTP and does not hydrolyze the nucleotide?

Answer 12

A tubulin

Question 13

What tubulin hydrolysis and exchanges the bound nucleotide?

Answer 13

B tubulin

Question 14

A tubulin is bound to what and what is B tubulin?

Answer 14

a tubulin is bound to GTP whereas b tubulin is GDP-bound

Question 15

What direction does kinesis go in while transporting cargo on microtubule tracks?

Answer 15

to positive end

Question 16

What microtubule tracks goes to negative end?

Answer 16

Dynein

Question 17

What initiates transcription?

Answer 17

promoter (TATA box)

Question 18

what is the role of the TATA box?

Answer 18

Recruits general transcription factors

Question 19

What does the general transcription factor recruit?

Answer 19

RNA polymerase

Question 20

What direction does transcription run?

Answer 20

5’ to 3’ of coding strand

Question 21

What is polyadenylation?

Answer 21

(poly A tail) the process where Adenines added to the 3’ end of the mRNA

Question 22

What are the three steps mRNA needs to go through before it is able to be transported out of the nucleus?

Answer 22

Capped, polyadenylated, spliced

Question 23

What is the role of nuclear lamina?

Answer 23

Structural support (intermediate filament)

Question 24

What are the most abundant and largest protein complexes in the cell?

Answer 24

Ribosome

Question 25

What is the role of tRNA synthase?

Answer 25

links proper amino acid to the corresponding tRNA

Question 26

What is the start codon?

Answer 26

ATG

Question 27

What happens at each site of the ribosome?

Answer 27

A site - first binding site of aminoacyl-tRNA P site - tRNA linked to the polypeptide E site - Exit site for the tRNA

Question 28

What is the chaperone Hsp 70 responsible for?

Answer 28

binds to hydrophobic regions and prevents aggregation of unfolded protein (gives the protein enough time to find the proper fold)

Question 29

What is the chaperon Hsp60 responsible for?

Answer 29

forms a large cavity that separated the unfolded protein from the cytosol and thus prevents aggregation

Question 30

What is the function of the ER?

Answer 30

Protein translocation, protein folding, protein glycosylation, protein quality control, calcium ion storage

Question 31

Where are transmembrane proteins and soluble lumenal proteins translated?

Answer 31

At the ER

Question 32

What terminus is luminal and which one is in the cytosol?

Answer 32

The N-terminus is lumenal, the C-terminus is in the cytosol

Question 33

What occurs in the N-linked glycosylation?

Answer 33

modification of the amino group

Question 34

What occurs during O-linked glycosylation?

Answer 34

modification of a OH group

Question 35

What happens to most proteins that are translated and translocated at the ER?

Answer 35

Become glycosylated

Question 36

What can glycosylation help with?

Answer 36

can increase stability of secreted proteins

Question 37

Why is glycosylation of surface proteins important?

Answer 37

for recognition of self versus foreign (immune system)

Question 38

In hydropathy, what does a positive number indicate?

Answer 38

hydrophobic

Question 39

What are Rab proteins?

Answer 39

small GTPases that act as regulators/switches

Question 40

Explain vesicle fusion with the golgi

Answer 40

the ER derived vesicles uncoat, tether with the Golgi, dock and fuse with the Golgi membrane

Question 41

What does small GTPases require to hydrolyze GTP and exchange GDp with GTP?

Answer 41

Require GAPs and GEFs

Question 42

What is the role of the golgi apparatus?

Answer 42

Protein sorting

Question 43

What side of the golgi aparatus receives vesicles?

Answer 43

cis side

Question 44

what side of the golgi forms transport vesicles that traffic to the endosome or the cell surface?

Answer 44

trans side

Question 45

What occurs in constitutive secretion?

Answer 45

delivery of plasma membrane proteins

Question 46

What is regulated secretion?

Answer 46

mainly used for secretion of regulatory proteins (insulin), fusion of vesicle with plasma membrane is regulated

Question 47

What is phagocytosis?

Answer 47

engulfing of large particles and performed by macrophages

Question 48

What is pinocytosis?

Answer 48

uptake of fluid-filled vesicles that are formed by clathrin

Question 49

What is the lysosome/vacuoles?

Answer 49

Acidic compartment with a large number of enzymes that degrade macromolecules

Question 50

What is a proteasome?

Answer 50

large protein complex that degrades poly-ubiquitinated proteins

Question 51

What is autophagy induced by?

Answer 51

starvation

Question 52

What is responsible for the degradation of soluble proteins in both the cytoplasm and the nucleus?

Answer 52

the proteasome

Question 53

What is autophagy?

Answer 53

is a degradation pathway for organelles and other large structures

Question 54

What does starvation cause?

Answer 54

the degradation of cytoplasmic proteins by autophagy which releases amino acids important to survive the starvation conditions

Question 55

What occurs during M phase of the cell?

Answer 55

cell divides

Question 56

What happens during G1 and S phase of the cell cylcle?

Answer 56

the cell grows in g1 and DNA replicate in S

Question 57

What phase is interphase?

Answer 57

G1, S, G2

Question 58

What is the cell cycle controlled by?

Answer 58

Cyclin-dependent kinases (CDKs)

Question 59

What chemical reaction do CDks assist with?

Answer 59

Phosphorylation of proteins that are responsible for the cell cycle

Question 60

Cyclins are ubiquinated and degraded by what?

Answer 60

proteasome