CBSE Grade-12 Biology | 5. MOLECULAR BASIS OF INHERITANCE by Pavan | Learn Smarter
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5. MOLECULAR BASIS OF INHERITANCE

The chapter explores the molecular basis of inheritance, focusing on the structure and function of DNA and RNA, the mechanisms of replication, transcription, and translation, and the regulation of gene expression. It highlights significant historical experiments that elucidated the nature of genetic material, including the Hershey-Chase experiment and the Human Genome Project. The chapter also discusses the applications of DNA fingerprinting and the implications of genetic research in understanding hereditary traits and human biology.

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Sections

  • 5

    Molecular Basis Of Inheritance

    This section elaborates on the molecular structures and processes underlying inheritance, emphasizing DNA, genetic material, and RNA functions.

    Learning Practice

  • 5.1

    The Dna

    DNA, deoxyribonucleic acid, is a long polymer that acts as the genetic material for most organisms, forming a double helix structure that is crucial for replication and gene expression.

    Learning Practice

  • 5.1.1

    Structure Of Polynucleotide Chain

    The section discusses the chemical structure and significance of polynucleotide chains, primarily focusing on DNA and RNA.

    Learning Practice

  • 5.1.2

    Packaging Of Dna Helix

    This section discusses how the incredibly long DNA helix is compactly organized within cells.

    Learning Practice

  • 5.2

    The Search For Genetic Material

    This section outlines the historical quest for the genetic material, leading to the identification of DNA as the key hereditary substance through a series of pivotal experiments.

    Learning Practice

  • 5.2.1

    The Genetic Material Is Dna

    This section establishes that DNA is the primary genetic material in most organisms, revealing its structure, functions, and significance compared to RNA.

    Learning Practice

  • 5.2.2

    Properties Of Genetic Material (Dna Versus Rna)

    This section discusses the contrasting properties and roles of DNA and RNA as genetic material.

    Learning Practice

  • 5.3

    Rna World

    RNA is believed to be the first genetic material, playing crucial roles in both genetic information storage and catalytic processes in early life forms.

    Learning Practice

  • 5.4

    Replication

    This section discusses the process of DNA replication, which is semiconservative, meaning that each new DNA molecule consists of one old strand and one new strand.

    Learning Practice

  • 5.4.1

    The Experimental Proof

    This section discusses the experimental proof of semiconservative DNA replication, initially demonstrated by Meselson and Stahl using E. coli.

    Learning Practice

  • 5.4.2

    The Machinery And The Enzymes

    This section discusses the key enzymes involved in DNA replication and their roles in ensuring efficient, accurate, and rapid DNA synthesis.

    Learning Practice

  • 5.5

    Transcription

    Transcription is the process of synthesizing RNA from a DNA template, crucial in the flow of genetic information.

    Learning Practice

  • 5.5.1

    Transcription Unit

    The transcription unit consists of three key regions essential for the synthesis of RNA from DNA: a promoter, a structural gene, and a terminator.

    Learning Practice

  • 5.5.2

    Transcription Unit And The Gene

    This section discusses the concept of a transcription unit in DNA, emphasizing the definition of a gene and the distinctions between monocistronic and polycistronic organisms.

    Learning Practice

  • 5.5.3

    Types Of Rna And The Process Of Transcription

    This section discusses the different types of RNA involved in protein synthesis and describes the transcription process.

    Learning Practice

  • 5.6

    Genetic Code

    The genetic code is a set of rules that dictates how sequences of nucleotides in DNA and RNA are translated into amino acids to form proteins.

    Learning Practice

  • 5.6.1

    Mutations And Genetic Code

    This section examines how mutations affect genetic code and the implications for protein synthesis, highlighting examples like sickle cell anemia.

    Learning Practice

  • 5.6.2

    Trna– The Adapter Molecule

    tRNA serves as the crucial adapter molecule that translates the genetic code into amino acids during protein synthesis.

    Learning Practice

  • 5.7

    Translation

    Translation is the process of synthesizing polypeptides from mRNA, leveraging the genetic code defined by nucleotide sequences.

    Learning Practice

  • 5.8

    Regulation Of Gene Expression

    This section discusses the regulation of gene expression at various levels in both prokaryotes and eukaryotes.

    Learning Practice

  • 5.8.1

    The Lac Operon

    The lac operon is a model system for understanding gene regulation in bacteria, specifically how lactose metabolism is controlled.

    Learning Practice

  • 5.9

    Human Genome Project

    The Human Genome Project aimed to sequence the entire human genome to understand genetic makeup and its implications for health and disease.

    Learning Practice

  • 5.9.1

    Salient Features Of Human Genome

    The section discusses key characteristics of the human genome as uncovered by the Human Genome Project.

    Learning Practice

  • 5.9.2

    Applications And Future Challenges

    Understanding DNA sequences will shape future biological research and necessitate collaboration among diverse scientists.

    Learning Practice

  • 5.10

    Dna Fingerprinting

    DNA fingerprinting is a technique used to identify genetic differences between individuals, utilizing variations in repetitive DNA sequences.

    Learning Practice

References

NCERT Study Material

Class Notes

Memorization

What we have learnt

  • DNA is the genetic material...
  • The double helix structure ...
  • The regulation of gene expr...

Final Test

Revision Tests