Class XII · Biology practice

Principles of Inheritance and Variation MCQs

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519 questions in this collection · Page 18 of 52

Question 171 of 519
📘 CLASS XII

Principles Of Inheritance And Variation

Which bond stabilizes the double-helix structure of DNA by holding complementary bases together?
Weak hydrogen bonds form between complementary base pairs (A-T and G-C), linking the two antiparallel strands of the DNA helix.
Question 172 of 519
📘 CLASS XII

Principles Of Inheritance And Variation

The enzyme that joins the Okazaki fragments on the lagging strand during DNA replication is:
DNA Ligase seals the nicks between the fragmented segments (Okazaki fragments) created during the discontinuous synthesis of the lagging strand.
Question 173 of 519
📘 CLASS XII

Principles Of Inheritance And Variation

In the context of the genetic code, the term 'degenerate' means:
The genetic code is degenerate because multiple codons (triplets) can code for the same single amino acid.
Question 174 of 519
📘 CLASS XII

Principles Of Inheritance And Variation

During protein synthesis, the anticodon is found on which molecule?
The transfer RNA (tRNA) molecule contains the anticodon loop, which is complementary to the codon on the mRNA, allowing it to bring the correct amino acid to the ribosome.
Question 175 of 519
📘 CLASS XII

Principles Of Inheritance And Variation

What are the non-coding sequences within a eukaryotic gene that are removed during mRNA processing?
Introns are intervening, non-coding sequences that are spliced out from the pre-mRNA (hnRNA), leaving the coding sequences (exons) to form the mature mRNA.
Question 176 of 519
📘 CLASS XII

Principles Of Inheritance And Variation

Which of the following is found in RNA but not in DNA?
RNA contains the base Uracil (U) instead of Thymine (T), and its sugar is Ribose instead of Deoxyribose.
Question 177 of 519
📘 CLASS XII

Principles Of Inheritance And Variation

The process of 'splicing' in eukaryotes involves:
Splicing is the step in post-transcriptional processing where non-coding introns are excised from the primary transcript and the coding exons are ligated together to produce mature mRNA.
Question 178 of 519
📘 CLASS XII

Principles Of Inheritance And Variation

The strand of DNA that is copied during transcription is called the:
RNA polymerase reads the template strand (usually 3' to 5') to synthesize the RNA molecule (5' to 3'), which will be complementary to the template strand.
Question 179 of 519
📘 CLASS XII

Principles Of Inheritance And Variation

What is the primary function of ribosomes in a cell?
Ribosomes are the cellular machinery responsible for translation, where they read the mRNA sequence and synthesize a polypeptide chain (protein).
Question 180 of 519
📘 CLASS XII

Principles Of Inheritance And Variation

Which type of bond links amino acids together to form a polypeptide chain?
Peptide bonds are covalent bonds formed between the carboxyl group of one amino acid and the amino group of the next during translation.
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