CHAPTER 15

Question 1

AMINO acids

Answer 1

monomers of proteins

Question 2

the amino acids in proteins are joined together by

Answer 2

peptide bonds to form polypeptide chains

Question 3

peptide bond

Answer 3

attaches tot he carboxyl group of one amino acid and amino group of another

Question 4

how many possible codons are there

Answer 4

64

Question 5

genetic code (condon)

Answer 5

genetic code which consists of three amino acids

Question 6

how many sense codons are there

Answer 6

61 because 3 are stop codons

Question 7

degenerate

Answer 7

there is 61 codons and only 20 different amino acids so code contains more information than is needed to specify amino acids

• code is redundant
  amino acids may be specified by more than one codon

Question 8

synonymous codons

Answer 8

codons that specify the same amino acids

Question 9

wobble hypothesis

Answer 9

nonstandard pairings of bases could take place at the third position of a codon

• allow some trnas to pair with more than one mrna codon

Question 10

start codon

Answer 10

first codon of mrna to specidy an amino acid

Question 11

stop codons

Answer 11

UAA, UAG, AND UGA do not encode aminod acids and signals end of trnalation

Question 12

where does translation take place

Answer 12

on ribosomes

Question 13

four stages of protein synthesis

Answer 13

1. trna bind to amino acids
2. initiation
3. elongation - amino acids are joined one at a time to growing polypeptide chain
   termination - protein synthesis halts at termination codon

Question 14

trna charging

Answer 14

attachment of a trna to its appropiate amino acid requires energy from ATP

Question 15

initiation of translation

Answer 15

1. mrna binds to small subunit of ribosome
2. initiator tRNA binds to mRNA through base pairin between intiation codon and anticodon
3. large ribosomal subunit joins initiation complec