Protein synthesis

Question 1

proteins are synthesized at the ____

Answer 1

ribosome

Question 2

During the process of translation, proteins are synthesized at the ____ by linking ___ ____ together in the order specified by the sequence of codons in mRNA

Answer 2

ribosome, amino acids

Question 3

prokaryotes are know as the ____S ribosomes

Answer 3

70

Question 4

eukaryotes are known as the ___S ribosomes

Answer 4

80

Question 5

what are the two parts of the prokaryotic ribosomes?

Answer 5

30S, 50S

Question 6

what are the two parts of the eukaryotic ribosomes?

Answer 6

40S, 60S

Question 7

a prokaryote can contain ____ ribosomes and a eukaryote can contain _____

Answer 7

20,000, 200,000

Question 8

what percent rRNA is the small pro subunit (30S)?

Answer 8

60

Question 9

what percent rRNA is the large pro subunit (50S)?

Answer 9

70

Question 10

what percent rRNA is the small euk subunit (40S)?

Answer 10

50

Question 11

what percent rRNA is the large euk subunit (60S)?

Answer 11

65

Question 12

What are the three phases of protein synthesis?

Answer 12

initiation, elongation, and termination

Question 13

Involves binding of mRNA to the small and large ribosomal subunits, and binding of an initiator tRNA

Answer 13

initiation

Question 14

Includes the formation of all peptide bonds of the growing polypeptide chain.

Answer 14

elongation

Question 15

Occurs when a “stop” codon is reached along the mRNA, which leads to the release of the completed polypeptide.

Answer 15

termination

Question 16

what is the purpose of the gap between the ribosomal subunits?

Answer 16

mRNA goes through, RNA, growing protein chain

Question 17

where does the new amino acid bind to the ribosome?

Answer 17

A site

Question 18

at what site does the growing polypeptide growing?

Answer 18

P site

Question 19

at what site is the exit site for tRNA

Answer 19

E site

Question 20

what holds the growing chain to the P site?

Answer 20

the anticodon and tRNA

Question 21

pro: EF-Tu

Answer 21

eEf1(alpha)

Question 22

pro: EF-Ts

Answer 22

eEF1(beta)(gamma)

Question 23

pro: EF-G

Answer 23

eEF2

Question 24

what is the eukaryotic release factor?

Answer 24

eRF1

Question 25

what are the prokaryotic release factors?

Answer 25

RF-1, RF-2, RF-3

Question 26

initiation begins with the binding of ____ and the ___ _____ to the 30S ribosomal subunit

Answer 26

mRNA, initiator tRNA

Question 27

all other parts of the growing chain attach to the ___ site except for the initiator, which attaches to the ___ site

Answer 27

A, P

Question 28

what happens to GTP during initiation?

Answer 28

breaks down into GDP

Question 29

what it the anticodon sequence of f-met-tRNA?

Answer 29

5’CAU3’

Question 30

The 70S initiation complex consists of the __ and __ ribosomal subunits, mRNA, and the initiator tRNA bound to the P site

Answer 30

30S and 50S

Question 31

The mRNA and ___ are in the gap between the two subunits

Answer 31

tRNA

Question 32

What else is involved in the initiation of protein synthesis?

Answer 32

The initiation factors IF-1, IF-3, IF-2, and GTP are also required

Question 33

The initiator ___ binds to the P site on the 30S subunit, and the ___ subunit joins the 30S subunit

Answer 33

tRNA, 50S

Question 34

The initiator tRNA of E coli is

Answer 34

f-Met-tRNA

Question 35

during peptide chain elongation, the first stage is the binding of a new ______ to the A site

Answer 35

aminoacyl-tRNA

Question 36

what elongation factor brings about the binding of a new aminoacyl-tRNA to the A Site?

Answer 36

EF-Tu

Question 37

what elongation factor recycles EF-Tu after it binds an aminoacyl-tRNA?

Answer 37

EF-Ts

Question 38

the ____ _____ activity is not due to a protein enzyme, but is due to an RNA enzyme activity of the peptidyl transferase center of the 23S rRNA and the 50S subunit

Answer 38

peptidyl transferase

Question 39

translocation of the peptide chain back to the P site is brought about by elongation factor _____

Answer 39

EF-G

Question 40

Peptidyl transfer is the step that forms the ___ ___ between the new amino acid and the growing polypeptide chain

Answer 40

peptide bond

Question 41

The elongation cycle requires what three factors?

Answer 41

EF-Tu, EF-Ts, EF-G

Question 42

activated EF-TU is required for aminoacyl-tRNA to bind, and it is activated by ____

Answer 42

GTP

Question 43

____ is the second enzyme in addition to EF-TU that needs to be activated by GTP

Answer 43

EF-G

Question 44

The binding of release factors to the A site transforms the ___ ___ ___, that forms the peptide bond between amino acids, into a hydrolase.

Answer 44

ribosomal peptidyl transferase

Question 45

The peptidyl transferase then ____ the bond linking the polypeptide to its tRNA carrier, thereby releasing the polypeptide

Answer 45

hydrolyzes

Question 46

the presence of a ___ ____ at the A site brings about the binding of 2 release factors to the A site (always at lease RF-3) along with GTP

Answer 46

stop codon

Question 47

the biding of release factors to the A site transforms the ribosomal peptydyl transferase into a ____, which breaks covalent bonds

Answer 47

hydrolase

Question 48

after dissocitation, there is ___ ____ between the pool of 50S ribosomes and 30S ribosomes

Answer 48

dynamic equillibrium

Question 49

a ____ is multiple ribosomes synthesizing proteins on a single mRNA molecule

Answer 49

polysome

Question 50

prokaryotic mRNAs can have up to _____ ribosomes attached

Answer 50

10

Question 51

what are Hsp70, GroES/GroEL exmaples of?

Answer 51

molecular chaperones that aide in the folding of proteins into the cell

Question 52

_____ percent of proteins require GroES/GroEL to fold (all else requires either none or Hsp70)

Answer 52

15 %

Question 53

After the 70S ribosomes dissociate from the mRNA, the ribosomes separate into free __ and ___ subunits

Answer 53

30S and 50S