Study how the lac operon controls gene expression in bacteria in response to lactose. Review the components and regulation mechanisms with practice questions.
Single-strand binding proteins (SSBs) prevent the reannealing of separated DNA strands during replication.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
A repressible operon, such as the trp operon, is normally on but can be turned off when a repressor binds to it.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
The lac operon is an inducible operon that is activated in the presence of lactose to allow lactose metabolism.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
A silent mutation changes a nucleotide sequence but does not alter the amino acid sequence due to redundancy in the genetic code.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
rRNA does not carry genetic information; that function is performed by mRNA.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
An inducible operon, like the lac operon, is normally off but can be activated by an inducer (e.g., lactose).
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
Reverse transcriptase synthesizes complementary DNA (cDNA) from an mRNA template.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
mRNA (messenger RNA) carries genetic information from DNA to the ribosome for protein synthesis.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
DNA replication is semi-conservative because each new molecule contains one parental and one new strand.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
A nonsense mutation introduces a premature stop codon, leading to an incomplete and often nonfunctional protein.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
rRNA (ribosomal RNA) is the structural and catalytic component of ribosomes, aiding in protein synthesis.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
An inducible operon (such as the lac operon) is normally off but can be activated by an inducer like lactose.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
