The backbone of the DNA strand is formed by the alternating sugar (deoxyribose) and phosphate groups. The nitrogenous bases project inwards from this backbone.
Question 102 of 668
📘 CLASS XII
The reading frame of mRNA is shifted by?
Insertions or deletions of nucleotides (not in multiples of 3) shift the reading frame of the ribosome, altering the amino acid sequence downstream of the mutation.
Question 103 of 668
📘 CLASS XII
If the ratio of (A+T)/(G+C) in one strand is 0.7, what is it in the complementary strand?
Since A pairs with T and G pairs with C, the amount of A+T on one strand equals the amount of T+A on the complementary strand. The same applies to G+C. Therefore, the ratio (A+T)/(G+C) remains the same for both strands.
Question 104 of 668
📘 CLASS XII
Which enzyme is used to synthesize DNA from an RNA template (Reverse Transcription)?
Reverse Transcriptase is an enzyme found in retroviruses that synthesizes a complementary DNA (cDNA) strand using an RNA template, reversing the central dogma flow.
Question 105 of 668
📘 CLASS XII
H2A, H2B, H3, and H4 occur in the nucleosome as?
The histone core consists of two molecules each of H2A, H2B, H3, and H4, forming an octamer (8 units) around which DNA wraps.
Question 106 of 668
📘 CLASS XII
The process of translation occurs in the?
Translation, the synthesis of proteins from mRNA, takes place on ribosomes located in the cytoplasm (or on the rough ER) of the cell.
Question 107 of 668
📘 CLASS XII
The start codon AUG codes for which amino acid?
AUG is the universal start codon and it specifically codes for the amino acid Methionine. In prokaryotes, it codes for formylated-methionine.
Question 108 of 668
📘 CLASS XII
How many nitrogen atoms are present in a Purine ring?
A purine ring consists of a nine-membered double-ring structure containing 4 nitrogen atoms at positions 1, 3, 7, and 9.
Question 109 of 668
📘 CLASS XII
Which bonds hold the two DNA strands together?
The two strands of the double helix are held together by hydrogen bonds between complementary nitrogenous bases (A-T and G-C).
Question 110 of 668
📘 CLASS XII
In a nucleoside, the nitrogen base is attached to which carbon of the sugar?
The nitrogenous base is always attached to the C1 (1-prime) carbon of the pentose sugar via the N-glycosidic bond.
