20.5 - The Genetic Code

Question 1

what does mRNA carry

Answer 1

it carries the genetic code for a protein

Question 2

the genetic code is indeed a

Answer 2

triplet code

Question 3

Each group of three nucleotides in the sequence of the mRNA is called a

Answer 3

codon

Question 4

each codon codes for a

Answer 4

single amino acid

Question 5

a three-letter genetic code contains sixty-four words, called____ but there are only ___ amino acids

Answer 5

codons

20

Question 6

there are _______ than are required to specify all of the amino acids found in proteins.

Answer 6

44 more codons

Question 7

Three of the codons—________—specify termination signals for the process of translation.

Answer 7

UAA, UAG, and UGA

Question 8

Francis Crick (recall Watson and Crick and the double helix) proposed that the genetic code is a

Answer 8

degenerate code

Question 9

The term degenerate is used to indicate that different triplet codons may serve as code words for the

Answer 9

same amino acid

Question 10

methionine and tryptophan are the only amino acids that have a

Answer 10

single codon

Question 11

erine and leucine have

Answer 11

6 codons each

Question 12

the rest amino acids have atleast

Answer 12

2 codons

Question 13

The genetic code is also somewhat

Answer 13

mutation resistant

Question 14

For those amino acids that have multiple codons, the first two bases are _____ and thus identify the amino acid, and only the third position is _____.

Answer 14

often identical

variable

Question 15

Mutations—changes in the nucleotide sequence—in _______ therefore often have no effect on the amino acid that is incorporated into a protein.

Answer 15

the third position