Lippincott - Protein Synthesis

Question 1

direction of writing of codon

Answer 1

5’–>3’

Question 2

number of base combinations

Answer 2

64

Question 3

number of codons coding for amino acids

Answer 3

61

Question 4

stop codons

Answer 4

UAA, UAG, UGA

Question 5

start codon

Answer 5

AUG

Question 6

protein coded for by start codon

Answer 6

methionine

Question 7

characteristics of genetic code [4]

Answer 7

[1] specificity / unambiguity
[2] universality
[3] redundance / degeneracy
[4] nonoverlapping

Question 8

specificity of genetic code

Answer 8

a particular codon codes for only one amino acid

Question 9

universality of genetic code

Answer 9

genetic code found in all organisms

Question 10

redundance / degeneracy of genetic code

Answer 10

a single amino acid has more than 1 coding codon

Question 11

nonverlapping / commaless

Answer 11

code is read from a fixed starting point as a continuous sequence of bases

Question 12

consequences of altering nucleotide sequence [6]

Answer 12

[1] silent mutation
[2] missense
[3] nonsense
[4] triple repeat expansion
[5] splice site mutation
[6] frameshift

Question 13

silent mutation

Answer 13

single nucleotide mutation does not change the amino acid sequence

Question 14

missense

Answer 14

single nucleotide mutation changes amino acid sequence

Question 15

nonsense

Answer 15

single nucleotide mutation produces stop codon

Question 16

result of nonsense mutation

Answer 16

truncated protein

Question 17

triple repeat expansion

Answer 17

amplification of a codon resulting in abnormally high amounts of a single amino acid

Question 18

splice site mutations

Answer 18

failure to correctly splice the protein

Question 19

frameshift mutation

Answer 19

addition or deletion causes change in reading frame and abnormal protein

Question 20

how is amino acid linked to tRNA

Answer 20

carboxyl group of AA is in ester linkage with adenosine of CCA at 3’ end

Question 21

anticodon

Answer 21

complement of codon in mRNA

Question 22

codon

Answer 22

specifies amino acid needed for the sequence

Question 23

responsible for attachment of AA to tRNA

Answer 23

aminoacyl-tRNA synthetase

Question 24

mediators of circularization of mRNA preventing use of incompletely processed mRNA in translation

Answer 24

eIF-4 proteins, poly-A binding proteins

Question 25

where do eIF-4 proteins bind?

Answer 25

5' cap

Question 26

prokaryotic ribosomal components

Answer 26

70S = 50S + 30S

Question 27

eukaryotic ribosomal components

Answer 27

80S = 60S + 40S

Question 28

[T\F] ribosomal proteins are more abundant in eukaryotic ribosomes

Answer 28

T

Question 29

products of RER ribosomes

Answer 29

proteins for export

Question 30

products of cytosolic ribosomes

Answer 30

proteins for the cell's own use

Question 31

wobble hypothesis

Answer 31

movement of first anticodon base allows nontraditional pairing with 3rd base of codon, allowing tRNA to recognize more than 1 codon --> more flexible

Question 32

polycistronic synthesis

Answer 32

more than 1 coding region in mRNA

Question 33

monocistronic synthesis

Answer 33

only 1 coding region in mRNA

Question 34

type of coding in eukaryotes

Answer 34

monocistronic

Question 35

Shine-Dalgarno sequence

Answer 35

[1] purine rich sequence located upstream of AUG [2] ribosome can recognize SD sequence [3] binding or ribosome to SD sequence puts coding regions close to AUG

Question 36

direction of movement of ribosome along mRNA in translation

Answer 36

5' --> 3'

Question 37

sites of ribosome

Answer 37

A, P, E

Question 38

ribosome - A site

Answer 38

A (aminoacyl) site; first binding site for charged tRNA - specifies the next amino acid to be added to the chain

Question 39

ribosome - P site

Answer 39

P (peptidyl) site; second binding site for charged tRNA - carries chain of amino acids that have already been synthesized

Question 40

ribosome - E site

Answer 40

E (exit) site; third binding site for charged tRNA - occupied by empty tRNA about to exit

Question 41

elongation in transcription

Answer 41

addition of amino acids to carboxyl end of growing chain

Question 42

elongation factors

Answer 42

mediate the delivery of aminoacyl-tRNA to the mRNA template in the A site

Question 43

responsible for catalysis of peptide bond

Answer 43

peptidyltransferase

Question 44

translocation

Answer 44

process by which the ribosome moves forward 3 nucleotides after creating a successful peptide bond

Question 45

enzyme required for translocation in eukaryotes

Answer 45

EF-2-GTP

Question 46

release factor in eukaryotes

Answer 46

eRF

Question 47

polysomes

Answer 47

complex of 1 mRNA and a number of translating ribosomes

Question 48

important mechanism of translation regulation in eukaryotes

Answer 48

phosphorylation of eIF-2

Question 49

effect of eIF-2 phosphorylation

Answer 49

inactivation of protein, translation is not initiated

Question 50

cotranslational modification of protein

Answer 50

modification while protein is still attached to the ribosome

Question 51

posttranslational modification of protein

Answer 51

modification after synthesis has been completed

Question 52

trimming of proteins

Answer 52

proteins produced as large inactive complexes; cleavage/trimming is required to activate them

Question 53

examples of protein that uses trimming for regulation

Answer 53

inactive trypsinogen trimmed to become active trypsin

Question 54

covalent modifications that may activate or inactivate proteins [4]

Answer 54

[1] phosphorylation [2] glycosylation [3] hydroxylation [4] carboxylation

Question 55

mechanisms of protein folding [2]

Answer 55

[1] spontaneous | [2] nonspontaneous (through chaperone)

Question 56

chaperone

Answer 56

protein that facilitates the proper folding of other proteins