Question

The bond that links a base to a sugar is a glycosidic bond. What is the name of the kind of bond that links a sugar to a phosphate group?

Define the primary structure of DNA/RNA. Compare and contrast to the primary structure of proteins.

In proteins, a peptide read from the N terminal to the C terminal. Is there a kind of direction in DNA/RNA as well? Briefly explain.

Give the equation for Chargaff’s rules. What does it mean?

Who proposed DNA was a double helix? In what decade?

What kinds of forces hold the double strands of a DNA double helix together? Do the two strands go in the same direction or in opposite directions?

Hydrogen bonds can be disrupted by heat. Which base pair can withstand more heat based on the answer above?

When DNA replicates, how is it able to “unwind” its double helix?

Answer 1

Ester bond links a sugar to a phosphate group.

Primary Structure of DNA/RNA is sequence of nitrogenous bases in the nucleic acid chain.

Primary Structure of Protein is the linear chain of amino acids linked by peptide bonds. Hence, Proteins are also called polypeptides.

Yes DNA/RNA is also read from direction 5' to 3' like proteins (N terminal to C terminal). The polymer has at one end free phosphate moiety at 5' end of sugar, which is referred to as 5'- end. Similarly, at the other end of the polymer the sugar has a free OH of 3'C group which is referred to as 3'- end.

According to Erwin Chargaff for a double stranded DNA, the ratios between Adenine and Thymine and Guanine and Cytosine are constant and equals one.

[C+G] < [A+T]..... ( A = T and C = G )

We have to entitled answer only one question in case of long question and first four question in case of short question or MCQ.