The document discusses molecular biology focusing on gene expression regulation, including the processes of transcription, translation, and replication. It categorizes genes into constitutive and regulative types, with examples and details on prokaryotic and eukaryotic gene control mechanisms. Eukaryotic gene structure is highlighted, noting the presence of introns and exons.

1. MOLECULAR BIOLOGY

2. Contents
• Regulation of gene expression
• Recombinant DNA Technology
• Polymerase Chain Reaction

3. Regulation of gene expression

4. Gene Expression
 Formation of functional gene product, either RNA or protein, is
called gene expression
 Transcription+ Translation+ Replication= gene expression
• Gene expression determines
• How much ( quantity )
• When particular gene product will be made
• Provide basis for
 Cellular control
 Cellular differentiation
 Cellular functioning
 Morphogenesis
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5. Classification of genes wrt
expression
CONSTITUTIVE
• Those genes that are
continually expressed
and required for basic
cellular functioning
• Other name is HOUSE-
KEEPING GENES
• E.g. Actin gene
REGULATIVE
• Those genes that are
expressed only under
certain conditions
• These can be positively/
negatively regulated
• E.g. enzymes responsible
for glucose metabolism
only under influence of
insulin

6. Control of Gene Expression in
PROKARYOTES
Transcription
 Synthesis of RNA that is complementary to one of
the strands of DNA.
Translation
 Ribosomes read a messenger RNA and make protein
according to its instruction.
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7. Control of Gene Expression in
EUKARYOTES
 Transcription
 Post transcription
 Translation
 Post-translation
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8. Gene Structure of Eukaryotes
 Eukaryotic gene structure: Most eukaryotic genes in
contrast to typical bacterial genes, the coding
sequences (exons) are interrupted by noncoding DNA
(introns).
 On average, 7-10 exons spread over 10-16 kb of
DNA.
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