Sickle cell anemia is a classic example of which type of mutation?

[Molecular-Basis-of-Inheritance] [class-xii ]

• Frameshift mutation
• Point mutation
• Deletion mutation
• Duplication
Correct Option: B  [ Point mutation ]

Remark: Sickle cell anemia results from a point mutation (change of a single base pair) in the beta-globin gene, changing GAG to GUG.

Insertion or deletion of three or multiples of three bases results in?

[Molecular-Basis-of-Inheritance] [class-xii ]

• Frameshift mutation
• No change in reading frame
• Point mutation
• Silent mutation
Correct Option: B  [ No change in reading frame ]

Remark: Insertion or deletion of one or two bases causes frameshift, but insertion/deletion of three bases (or multiples of three) adds or removes whole amino acids without changing the reading frame of the rest.

The secondary structure of tRNA is depicted as?

[Molecular-Basis-of-Inheritance] [class-xii ]

• L-shaped
• Clover-leaf
• Double helix
• Linear
Correct Option: B  [ Clover-leaf ]

Remark: The 2D (secondary) structure of tRNA resembles a clover-leaf, while the 3D structure looks like an inverted L.

Which arm of tRNA binds to the amino acid?

[Molecular-Basis-of-Inheritance] [class-xii ]

• Anticodon loop
• 3-prime end
• 5-prime end
• DHU loop
Correct Option: B  [ 3-prime end ]

Remark: The amino acid attaches to the 3-prime end (Acceptor arm) of the tRNA molecule.

The process of activation of amino acids and their attachment to tRNA is called?

[Molecular-Basis-of-Inheritance] [class-xii ]

• Transcription
• Charging of tRNA (Aminoacylation)
• Translation
• Polymerization
Correct Option: B  [ Charging of tRNA (Aminoacylation) ]

Remark: Charging or aminoacylation of tRNA is the process where amino acids are activated by ATP and linked to their cognate tRNA.

Which rRNA acts as a ribozyme for peptide bond formation in bacteria?

[Molecular-Basis-of-Inheritance] [class-xii ]

• 16S rRNA
• 23S rRNA
• 5S rRNA
• 18S rRNA
Correct Option: B  [ 23S rRNA ]

Remark: In prokaryotes, the 23S rRNA component of the large ribosomal subunit acts as the enzyme (ribozyme) Peptidyl Transferase to form peptide bonds.

In the Lac Operon, the gene "z" codes for?

[Molecular-Basis-of-Inheritance] [class-xii ]

• Permease
• Transacetylase
• Beta-galactosidase
• Repressor
Correct Option: C  [ Beta-galactosidase ]

Remark: The lacZ gene codes for Beta-galactosidase, which hydrolyzes lactose into glucose and galactose.

The repressor protein of the Lac Operon is synthesized by which gene?

[Molecular-Basis-of-Inheritance] [class-xii ]

• z gene
• y gene
• a gene
• i gene
Correct Option: D  [ i gene ]

Remark: The "i" gene (inhibitor gene) codes for the repressor protein of the Lac Operon.

Lactose acts as an inducer by binding to the?

[Molecular-Basis-of-Inheritance] [class-xii ]

• Promoter
• Operator
• Repressor
• RNA Polymerase
Correct Option: C  [ Repressor ]

Remark: Lactose (or allolactose) binds to the repressor protein, causing a conformational change that prevents the repressor from binding to the operator, thus inducing the operon.

The Human Genome Project was coordinated by?

[Molecular-Basis-of-Inheritance] [class-xii ]

• US Department of Energy and NIH
• WHO
• European Union
• Indian Government
Correct Option: A  [ US Department of Energy and NIH ]

Remark: The HGP was a mega project coordinated by the U.S. Department of Energy and the National Institutes of Health (NIH).