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Molecular Basis of Inheritance
Which property of DNA double helix led Watson and Crick to hypothesise...

Which property of DNA double helix led W | Class 12 Biology Chapter Molecular Basis of Inheritance, Molecular Basis of Inheritance NCERT Solutions

Welcome to the NCERT Solutions for Class 12 Biology - Chapter Molecular Basis of Inheritance. This page offers a step-by-step solution to the specific question from Exercise 1, Question 5: . With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 5: Which property of DNA double helix led Watson and Crick to hypothesise semi-conservative mode of DNA replication? Explain.

Answer:

Watson and Crick observed that the two strands of DNA are anti-parallel and complementary to each other with respect to their base sequences. This type of arrangement in DNA molecule led to the hypothesis that DNA replication is semi-conservative. It means that the double stranded DNA molecule separates and then, each of the separated strand acts as a template for the synthesis of a new complementary strand. As a result, each daughter DNA molecule would have one parental strand and a newly synthesized daughter strand.

Since only one parental strand is conserved in each daughter molecule, it is known as semi-conservative mode of replication.

Parental and Daughter Strand

Other Questions of Chapter Molecular Basis of Inheritance

Q: List two essential roles of ribosome during translation.

Why is the Human Genome project called a mega project?

Now, sequencing of total genomes getting is getting less expensive day by the day. Soon it may be affordable for a common man to get his
genome sequenced. What in your opinion could be the advantage and disadvantage of this development?

Define an operon. giving an example, explain an Inducible operon.

Q: What is DNA fingerprinting? Mention its application.

Replication was allowed to take place in the presence of radioactive deoxynucleotides precursors in E.coli that was a mutant for DNA ligase. Newly synthesised radioactive DNA was purified and strands were separated by denaturation. These were centrifuged using density gradient centrifugation. Which of the following would be a correct result?

Q: Group the following as nitrogenous bases and nucleosides:
Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.

Q: In the medium where E. coli was growing, lactose was added, which induced the lac operon. Then, why does lac operon shut down some time after addition of lactose in the medium?

Q: If the sequence of the coding strand in a transcription unit is written as follows:
5-ATGCATGCATGCATGCATGCATGCATGC-3
Write down the sequence of mRNA.

Q: Explain (in one or two lines) the function of the followings:
(a) Promoter
(b) tRNA
(c) Exons

Popular questions of class 12 Biology

Q: What is spermatogenesis? Briefly describe the process of spermatogenesis.

Q: Why is reproduction essential for organisms? Answer

Q: Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals.

Q: With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.

Q: What is oogenesis? Give a brief account of oogenesis.

Q: Describe the structure of a seminiferous tubule.

Q: What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.

Q: With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.

Q: Explain the Law of Dominance using a monohybrid cross.

Q: What are sacred groves? What is their role in conservation?

Recently Viewed Questions of Class 12 Biology

Taking examples under each category, discuss upstream and downstream processing.

Name the first transgenic cow. Which gene was introduced in this cow?

Q: Diagrammatically represent the experimental steps in cloning and expressing an human gene (say the gene for growth hormone) into a bacterium like E. coli ?

Q: Explain what is meant by biofortification.

What is the main idea behind “Joint Forest Management Concept” introduced by the Government of India?

Q: If a population growing exponentially double in size in 3 years, what is the intrinsic rate of increase (r) of the population?

Q: Try to trace the various components of human evolution (hint: brain size and function, skeletal structure, dietary preference, etc.)

Which type of food would have lactic acid bacteria. Discuss their useful application.

Give the full form of ELISA. Which disease can be detected using it? Discuss the principle underlying the test.

Q: Explain briefly
(a) PCR
(b) Restriction enzymes and DNA
(c) Chitinase

Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

Read the question carefully and focus on the core concept being asked.
Reference examples and data from the chapter when answering questions about Molecular Basis of Inheritance.
Review previous year question papers to get an idea of how such questions may be framed in exams.
Practice answering questions within the time limit to improve your speed and accuracy.
Discuss your answers with your teachers or peers to get feedback and improve your understanding.

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Comments

Psycheversal
Jan 15, 2019

Aditya should clear his concepts because the semiconservative replication model was hypothesized first by Watson and Crick and later proved by Messelson and Stahl ok brooooooo

Aditya
Mar 21, 2018

This experiment was of melson and stahl and not of watson and crick bro