Chapter 14.6.1 (Exam 3) Code

Question 1

What is the role of the genetic code?

Answer 1

The genetic code specifies which amino acids will be used to build a protein

Question 2

What is a codon?

Answer 2

Codon: sequence of three bases, something like a three-letter “word”

Each codon specifies a particular amino acid (aa)

Question 3

What is the start codon? Which amino acid does it code for?

Answer 3

AUG - Methionine

Question 4

What are the stop codons? Do they code for any amino acids?

Answer 4

UAA UGA UAG

No, they do not

Question 5

Describe some important qualities of the genetic code.

Answer 5

For most amino acids, there is more than one codon—the genetic code is redundant

But the genetic code is not ambiguous—each codon specifies only one amino acid

The genetic code is nearly universal: the codons are the same in all organisms

Question 6

What are the 3 major players involved in translation?

Answer 6

mRNA (to synthesize a polypeptide)

Transfer RNA- links mRNA codons with specific amino acids

Ribosomes

Question 7

What are the 3 functions of each tRNA?

Answer 7

Get charged– get attached to its specific amino acid

Binds to mRNA at a triplet called the anticodon, which is complementary to an mRNA codon

Interacts with ribosomes, noncovalently

Question 8

Why aren’t there 61 different tRNAs for each individual codon?

Answer 8

Wobble base pairing occurs at the third position of the codon–anticodon interaction, the 3’ end of the codon

Wobble-base pairing results in different codons for the same amino acid being recognized by the same tRNA

Question 9

What is one example of wobble-base pairing?

Answer 9

Codons for phenylalanine—UUU and UUC—are recognized by the same tRNA