Chapter 15

Question 1

enzymes as a result of translation

Answer 1

mutations in genes can lead to nonfunctional enzymes

Question 2

auxotrophic mutants

Answer 2

cannot synthesize a particular amino acid because and enzyme in the biosynthesis pathway os broke by a mutation
1. give auxotrophic mutants a compound that comes after the broken enzyme in the pathway and the mutant will live
2. give auxotrophic mutants a compound that comes before the broken enzyme in the pathway and the mutant will not live

Question 3

what makes up an amino acid?

Answer 3

amino group, hydrogen, carboxyl group, and R group- side chain
the radical group gives each amino acid unique chemical properties- non polar allopathic, aromatic, positive or negative charge, etc.

Question 4

what bonds join amino acids?

Answer 4

peptide bonds

Question 5

primary protein structure

Answer 5

sequence of amino acids
determined by codons

Question 6

synonymous

Answer 6

codons that specify the same amino acid

Question 7

start codon is for ______

Answer 7

methionine

Question 8

secondary protein structure

Answer 8

folds and twists due to amino acid interactions

Question 9

tertiary protein structure

Answer 9

further folding due to secondary structure interactions

Question 10

quaternary protein structure

Answer 10

association among multiple polypeptides

Question 11

protein domains

Answer 11

self-stabilizing and independently functioning region of polypeptide chain; often has distinct function

Question 12

process of translation

Answer 12

1. tRNA charging
2. initiation (differences between bacteria and eukaryotes)
3. elongation
4. termination

Question 13

tRNA charging

Answer 13

1. tRNA joins with correct amino acid due to aminoacyl tRNA synthetase
2. requires ATP

Question 14

initiation (bacteria)

Answer 14

1. ribosome separates into small and large subunits
2. small subunit binds to Shine-Dalgrano sequence upstream of stop codon
3. initiation factors do something
4. GTP is hydrolyzed
5. large subunit joins to complete the ribosome

Question 15

initiation (eukaryotes)

Answer 15

1. initiation complex recognizes 5’ cap and binds there
2. Kozak sequence indicates start codon
3. mRNA is exported to cytoplasm
4. unmodified methionine is first amino acid

Question 16

elongation

Answer 16

1. helicase in small ribosomal subunit unwinds secondary structures in mRNA
2. charged tRNA come to A site of ribosome
3. peptide bond forms between AA in P site and AA in A site
4. tRNAs exit from the E site of the ribosome
5. ribosome moves 5’ to 3’ dow the mRNA molecule

Question 17

termination

Answer 17

1. no tRNA matches a stop codon
2. release factors help polypeptide, tRNA, and mRNA dissociate

Question 18

what is different about translation in bacteria?

Answer 18

translation can occur as a transcript is being produced

Question 19

post translational protein modifications

Answer 19

1. molecular chaperones help proteins fold properly
2. large precursors may be trimmed or cleaved
3. other chemical groups may be aded
4. signal sequences may be removed