Bihar Board - Class 12 Biology - Chapter 6: Molecular Basis of Inheritance Short Answer Question

Class 12th Bihar Board chapter Molecular Basis of Inheritance in Biology explain the structure and function of DNA, genetic code, and mechanisms of inheritance. Vidyakul provides comprehensive resources, including short-questions-answers, to help students understand the complex concepts and succeed in exams.

Short Answer type

Q.1. State the function of histones in DNA packaging.

A.1.

• They play a role in gene regulation.

• They help the DNA to wind around it.

• The histones are positively charged proteins, which can easily bind to the negatively charged DNA.

Q.2. What is the difference between heterochromatin and euchromatin?

A.2 Heterochromatin is a tightly packed DNA, which can be identified when stained in an extreme nuclear stain.

Euchromatin is a lightly packed DNA, which can be identified when stained in a less nuclear stain.

Q.3. Name any three viruses with RNA as the genetic material.

A.3. The viruses in which the genetic material is RNA is called the RNA virus. The three examples of the RNA virus.

1. Influenza Virus.

2. Hepatitis C Virus.

3. Human Immunodeficiency Virus.

Q.4. Give a reason for the discontinuous synthesis of DNA on one of the parental strands?

A.4. The biological process of DNA synthesis naturally occurs in 5′ to 3′ direction. In the double-stranded DNA, the strands are parallel and antiparallel to each other. During the synthesis of DNA, both the strands act as templates and only one (3′ to 5′ direction) can synthesize the parallel strand in 5’→3′ direction. The other strand 5′ to 3′ is synthesized in the opposite direction producing small stretches of DNA known as Okazaki fragments. This is the reason for the discontinuous synthesis of DNA on one of the parental strands.

Q.5. What is DNA polymorphism?

A.5. DNA’s polymorphism is the variation in the DNA sequence arising due to mutation at non-coding sequences.

Q.6. Retroviruses do not follow central dogma.  Comment on this statement

A.6. Retroviruses do not follow central dogma, because they possess RNA as genetic material instead of the DNA, which is later converted into DNA by the enzyme reverse transcriptase.

Q.7. Explain about the dual polymerase present in E.coli.

A.7. The DNA polymerase present in E.coli is a DNA dependent polymerase. This DNA polymerase helps in the:

1. Replication process.

2. Performs the 5′ to 3′ polymerase activity as well as 3′ to 5′ exonuclease activity.

3. The DNA polymerase III also has the ability to proofread the wrong nucleotides and substitute it with the correct one.

Q.8. Mention any two functions of AUG codon.

A.8. The AUG codon is also called the start codon. The two important functions of AUG codon include:

1. It codes for methionine.

2. It acts as an initiation codon for protein synthesis.

Q.9. What is the function of aminoacyl t-RNA synthetase?

A.9. Aminoacyl t-RNA synthase plays a major role in the biosynthesis of proteins by attaching an appropriate amino acid to the tRNA molecules.

Q.10. Explain the process of DNA fingerprinting in one definition.

A.10. DNA fingerprinting is a technique that is used to analyze the genetic makeup of living beings. It is widely used for DNA analysis in forensic tests and paternity tests to identify the biological parents of the child, and also to identify the criminal during forensic investigations.

Q.11. define the process of translation.

A.11. The translation is the process of protein synthesis in which the mRNA is used to synthesize proteins. The mRNA sequence is decoded to specify the amino acid of a polypeptide. The process of translation is carried out in the following steps:

• Initiation.

• Elongation.

• Termination.

Q.12. Mention any two applications of DNA fingerprinting.

A.12: (i) To identify criminals in the forensic laboratory.

(ii) To identify the real or biological parents in case of disputes.

(iii) To identify racial groups to rewrite the biological evolution.