GI: Genetic Code and Nucleic Acids

Question 1

Genetic code

Answer 1

The sequence of base triplets in mRNA which code for specific amino acids.

Question 2

How is genetic code read?

Answer 2

Each base triplet is read in sequence, separate from the triplet before it and after it.

Question 3

Give three characteristics of the genetic code:

Answer 3

1. Non-overlapping
2. Degenerate
3. Universal

Question 4

How is the genetic code non-overlapping?

Answer 4

Base triplets (codons) in mRNA don’t share their bases.

Question 5

How is the genetic code degenerate?

Answer 5

There are more possible combinations of triplets than there are amino acids, so some amino acids are coded for by more than one base triplet.

Question 6

How many possible combinations of triplets are there?

How many possible combinations of amino acids are there?

Answer 6

Triplets = 64

Amino acids = 20

Question 7

Start/stop triplets/codons

Answer 7

Tell the cell when to start and stop the production of the protein.

Question 8

How is the genetic code universal?

Answer 8

The same specific base triplets code for the same amino acids in all living things.

Question 9

Describe the relationship between DNA and mRNA:

Answer 9

mRNA is a complementary copy of DNA.

Question 10

Describe the relationship between tRNA anticodons and mRNA codons:

Answer 10

tRNA anticodons are complementary copies of mRNA codons

Question 11

What base from DNA is replaced in RNA and what is it replaced with?

Answer 11

T is replaced with U