Class 12 Molecular Basis of Inheritance MCQs with Answer

Class 12 Chemistry Molecular Basis of Inheritance MCQs with Answer

At Horizon Competition School, our Class 12 Chemistry MCQs on the Molecular Basis of Inheritance are meticulously designed to aid students in mastering this intricate topic. Covering essential concepts such as DNA replication, genetic code, mutations, and gene expression, these multiple-choice questions offer comprehensive preparation for Class 12 Chemistry exams.

Our MCQs challenge students to apply their understanding of molecular biology principles to solve problems effectively. With each question, students are encouraged to think critically and analyze genetic scenarios, enhancing their problem-solving skills.

Accompanied by detailed explanations, our MCQs provide invaluable insights into the underlying concepts, ensuring thorough comprehension. Students receive immediate feedback on their answers, enabling them to identify areas for improvement and track their progress effectively.

By practicing Class 12 Chemistry MCQs on the Molecular Basis of Inheritance at Horizon Competition School, students can build confidence, sharpen their analytical skills, and excel in their examinations.

Q1. If the base sequence of a codon in mRNA is 5′-AUG-3′, the sequence of tRNA pairing with it must be:

1. 5′ – UAC – 3′.
2. 5′ – CAU – 3′.
3. 5′ – AUG – 3′.
4. 5′ – GUA – 3′.

Q2. Who amongst the following scientists had no contribution in the development of the double helix model for the
structure of DNA?

1. Rosalind Franklin.
2. Maurice Wilkins.
3. Erwin Chargaff.
4. Meselson and Stahl.

Q3. With regard to mature mRNA in eukaryotes:

1. Exons and introns do not appear in the mature RNA.
2. Exons appear but introns do not appear in the mature RNA.
3. Introns appear but exons do not appear in the mature RNA.
4. Both exons and introns appear in the mature RNA.

Q4. The amino acid attaches to the tRNA at its:

1. 5′ – end.
2. 3′ – end.
3. Anti codon site.
4. DHU loop.

Q5. Which of the following are the functions of RNA?

1. It is a carrier of genetic information from DNA to ribosomes synthesising polypeptides.
2. It carries amino acids to ribosomes.
3. It is a constituent component of ribosomes.
4. All of the above.

Q6. Which was the last human chromosome to be completely sequenced:

1. Chromosome 1.
2. Chromosome 11.
3. Chromosome 21.
4. Chromosome x.

Q7. In some viruses, DNA is synthesised by using RNA as template. Such a DNA is called:

1. A-DNA.
2. B-DNA.
3. cDNA.
4. rDNA.

Q8. Control of gene expression takes place at the level of:

1. DNA-replication.
2. Transcription.
3. Translation.
4. None of the above.

Q9. While analysing the DNA of an organism a total number of 5386 nucleotides were found out of which the
proportion of different bases were: Adenine = 29%, Guanine = 17%, Cytosine = 32%, Thymine = 17%. Considering
the Chargaff’s rule it can be concluded that:

1. It is a double stranded circular DNA.
2. It is single stranded DNA.
3. It is a double stranded linear DNA.
4. No conclusion can be drawn.

Q10. The human chromosome with the highest and least number of genes in them are respectively:

1. Chromosome 21 and Y.
2. Chromosome 1 and X.
3. Chromosome 1 and Y.
4. Chromosome X and Y.

Q11. Both deoxyribose and ribose belong to a class of sugars called:

1. Trioses.
2. Hexoses.
3. Pentoses.
4. Polysaccharides.

Q12. If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is:
5′ – A T G A A T G – 3′,
The sequence of bases in its RNA transcript would be;

1. 5′ – A U G A A U G – 3′.
2. 5′ – U A C U U A C – 3′.
3. 5′ – C A U U C A U – 3′.
4. 5′ – G U A A G U A – 3′.

Q13. The promoter site and the terminator site for transcription are located at:

1. 3′ (downstream) end and 5′ (upstream) end, respectively of the transcription unit.
2. 5′ (upstream) end and 3′ (downstream) end, respectively of the transcription unit.
3. The 5′ (upstream) end.
4. The 3′ (downstream) end.

Q14. The fact that a purine base always paired through hydrogen bonds with a pyrimidine base leads to, in the DNA
double helix:

1. The antiparallel nature.
2. The semiconservative nature.
3. Uniform width throughout DNA.
4. Uniform length in all DNA

Q15. The DNA site where DNA-dependent RNA polymerase binds for transcription, is called.

1. Operator.
2. Promotor.
3. Regulator.
4. Receptor.