Question

How can four types of DNA nucleotides code for twenty different amino acid types?

a. Purines and pyrimidines form tRNA codes for each specific amino acid

b. Combinations of two purines and pyrimidines form codes for specific amino acids

c. Combination of two purines and pyrimidines form twenty codes for amino acids

d. Combinations of three of the four DNA nucleotide types can form sixty-four codes e. Each purine and pyrimidine form a code for a specific amino acid

Answer 1

Option D- Combinations of three of the four DNA nucleotide types can form sixty-four codes .

There 4 Types of Nucleotides based on the Presence of Nitrogen bases-Adenine ,uracil,Guanine,Cytosine.

But these 4 nucleotides can Code for 20 Aminoacids.

This is because,Combination of 3 nucleotides Out of the Four types of nucleotides can Result in 64 types of Codons.All these Codons Code for an aminoacid.Since Some of the codons Code for the same Aminoacid,there will only Production of 20 types of Amino acids.

That is these Nucleotiodes in a combination of three codes for an Amino acid.

For Example

UUU codes for Phenyl Alanine

UUA codes for Phenyl Alanine

UUG codes for Leucine

UUC codes for Leucine

Similarly ,there will be a total of 64 codons that codes for 20 different types of Aminoacids