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668 questions in this collection · Page 17 of 67
Question 161 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
Why is DNA more stable than RNA?
DNA is more stable because it is double-stranded (protection), lacks the reactive 2-prime hydroxyl group found in RNA, and contains Thymine which is more stable than Uracil.
Question 162 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
The presence of 2-prime OH in RNA makes it?
The 2-prime hydroxyl group in ribose makes RNA chemically reactive and prone to hydrolysis, making it less stable (labile) than DNA.
Question 163 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
RNA can act as a catalyst. Such RNA molecules are called?
RNA molecules that possess catalytic activity, behaving like enzymes, are termed Ribozymes (e.g., 23S rRNA).
Question 164 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
The "RNA World" hypothesis suggests that?
The hypothesis posits that RNA was the first genetic material because it can both store genetic information and catalyze chemical reactions essential for life.
Question 165 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
Meselson and Stahl used which organism for their experiment?
Meselson and Stahl used the bacterium Escherichia coli (E. coli) to demonstrate the semi-conservative nature of DNA replication.
Question 166 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
In the Meselson-Stahl experiment, N-15 is distinguished from N-14 by?
N-15 is a heavy isotope, not a radioisotope. It is distinguished from the lighter N-14 based on density differences using Cesium Chloride density gradient centrifugation.
Question 167 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
After one generation of replication in N-14 medium, E. coli DNA originally grown in N-15 showed?
After one generation, the DNA consisted of one old heavy strand (N-15) and one new light strand (N-14), resulting in a hybrid or intermediate density.
Question 168 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
Taylor used radioactive thymidine to prove semi-conservative replication in?
Taylor and colleagues used radioactive thymidine on the root tips of Vicia faba (faba beans) to show that eukaryotic chromosomes also replicate semi-conservatively.
Question 169 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
The enzyme DNA Helicase is responsible for?
Helicase unzips or unwinds the DNA double helix by breaking the hydrogen bonds between the nitrogenous bases.
Question 170 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
Single Stranded Binding (SSB) proteins function to?
SSB proteins bind to the separated DNA strands to prevent them from re-annealing (snapping back together) and protect them from degradation.