Class XII · Biology practice
Molecular Basis of Inheritance MCQs
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668 questions in this collection · Page 23 of 67
Question 221 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
Which bond is broken by the enzyme Helicase?
Helicase separates the two DNA strands by breaking the hydrogen bonds holding the nitrogenous bases together.
Question 222 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
The leading strand is synthesized in which direction?
The leading strand is synthesized continuously in the 5-prime to 3-prime direction, moving towards the replication fork.
Question 223 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
Which mutation results in the change of a single base pair?
A point mutation involves the substitution of a single base pair, as seen in Sickle Cell Anemia.
Question 224 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
Frameshift mutations are caused by?
Insertions or deletions of nucleotides (not in multiples of 3) shift the reading frame of the genetic code.
Question 225 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
The initiator tRNA in prokaryotes carries which amino acid?
In prokaryotes, the initiator tRNA is charged with N-formylmethionine (fMet). In eukaryotes, it is Methionine.
Question 226 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
Which site on the ribosome accepts the new incoming aminoacyl-tRNA?
The A-site (Aminoacyl site) is where the new tRNA carrying an amino acid enters the ribosome.
Question 227 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
During translation, the polypeptide chain is held at which site?
The P-site (Peptidyl site) holds the tRNA carrying the growing polypeptide chain.
Question 228 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
Termination of translation occurs when the ribosome encounters?
When a stop codon (UAA, UAG, UGA) reaches the A-site, no tRNA binds; instead, Release Factors bind to terminate translation.
Question 229 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
Which scientist proved that DNA replication is semi-conservative using Nitrogen isotopes?
Meselson and Stahl used N-15 and N-14 isotopes to prove the semi-conservative mode of replication.
Question 230 of 668
📘 CLASS XII
Molecular Basis Of Inheritance
What is the function of the enzyme Permease in the Lac Operon?
Permease facilitates the entry of lactose into the bacterial cell.
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