Class 12 Biology MCQ – Molecular Basis of Inheritance – Genetic Code


This set of Class 12 Biology Chapter 6 Multiple Choice Questions & Answers (MCQs) focuses on “Molecular Basis of Inheritance – Genetic Code”.

1. Which of the following refers to a proposition which directs the sequence of amino acids during protein synthesis?
a) DNA fingerprinting
b) Genetic Code
c) Transcription
d) Endolysis
View Answer

Answer: b
Explanation: The change in nucleic acids is responsible for the change in amino acids in the protein. This observation led to the proposition of genetic code. Genetic code is responsible for directing the sequence of amino acids during protein synthesis.

2. How many bases are required for coding 20 amino acids?
a) 1
b) 2
c) 3
d) 4
View Answer

Answer: d
Explanation: George Gamow who was a physicist mentioned that to be able to code for 20 amino acids, we require 4 bases. The code should also be made up of 3 nucleotides. The code should be made up of bases in a particular combination.

3. How many codons code for an amino acid?
a) 3
b) 8
c) 90
d) 61
View Answer

Answer: d
Explanation: There are a total of 64 codons. Among these 64 codons, 61 codons are responsible for coding the amino acids. The remaining 3 codons do not take part in producing the amino acids. On the other hand, they are responsible for stopping the production of amino acids. Hence, they are called as “Stop Codons”.
Note: Join free Sanfoundry classes at Telegram or Youtube

4. When is a codon said to be unambiguous?
a) When it codes for 2 amino acids
b) When it codes for 1 amino acids
c) When it codes for 3 amino acids
d) When it codes for 4 amino acids
View Answer

Answer: b
Explanation: One codon codes for only one amino acid. And so, the coding is said to be unambiguous and specific. In some cases, one amino acid is coded more than once by many codons. These are called are degenerates.

Sanfoundry Global Education & Learning Series – Biology – Class 12.

To practice all chapters and topics of class 12 Biology, here is complete set of 1000+ Multiple Choice Questions and Answers.

Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

Subscribe to his free Masterclasses at Youtube & discussions at Telegram SanfoundryClasses.