Question

1)
a) Explain the meaning and signifance of the fact that the genetic code is degenerate?

b) Briefly describe how complimentary base pairing explains:

- the structure of the DNA double helix
- DNA replication
- transcription
- binding of a codon to an anticodon

Answer 1

codon degeneracy means : 1 amino acid can be coded by more than one codon.

in genetic code system we have total 64 codons.

1 start codon three stop codon and remaining 60 codons are engaged in the coding function of 20 amino acids.

that is why we say that triplet codons have degeneracy property.

2. DNA helical structure: DNA is double helical structure in which 1 helix make interaction with another helix with the help of hydrogen bonds.

In the DNA we have nitrogenous bases purine and pyrimidine. purine make hydrogen bonding with pyrimidine

Adenine pairs with thymine with two hydrogen bonds.

Cytosine makes pairing with guanine with 3 hydrogen bonds.

due to this hydrogen bond the structure of double helix make stability.

when these hydrogen bonds broken down then double helix becomes separate and form to single helix.

DNA replication: the replication of DNA occurs when new nucleotides Incorporated complementary to the old strand.

DNA polymerase is an enzyme which polymerises the new strand by the use of nucleotides and attach complementary to the old strend.

replication of DNA fully depends on the complementary base pairing of nucleotides.

Transcription: in the process of transcription in the process of transcription RNA is formed by the sequence of DNA.

In in the structure of RNA we have nitrogenous bases similar to DNA that is adenine, guanine, cytosine and uracil.

RNA have you uracil nstead of thymine.

Binding of codon to anticodn: this relation occurs at the time of protein formation when anticodons of t RNA make binding with the clones of RNA.

anticodon t RNA have complementary triplet codon for m RNA. for example mRNA have codon CGC then tRNa with GCG complementary sequance binds with this mRNA.