Question

Which are true, and which are false?

a) Genetic material must encode phenotypes

b) Genetic material must contain nitrogen, but not sulfur

c) The structure of DNA is described as a double helix with two parallel strands.

d) Covalent (phosphodiester) bonds connect nucleotides in a strand; noncovalent (hydrogen) bonds hold strands into a double-stranded structure

e) All organisms contain DNA that is roughly 25% A, 25% T, 25% G, and 25% C.

f) A-, B-, and Z-form DNA are all right-handed helixes.

Answer 1

A.) False.

Some genetic material may not code for phenotype. And some genetic material may not even code for anything (Introns).

B.) True.

Genetic material consist of Nitrogen, Carbon, Hydrogen, Oxygen and Phosphorus.

C.) False.

The structure of DNA is described as a double helix with two anti-parallel strand.

D.) True.

Phosphodiester bond connects the nucleotide in a strand.

Two hydrogen bond is formed between A & T, three hydrogen bond is formed between G & C.

E.) False.

The ratio of A to T remains the same likewise the ratio of G to C remains the same in all organism with double stranded DNA as their genetic material. But the amount of these bases present in an organism varies.

F.) False.

Z- form is left handed, whereas A and B form are right handed.