Avery, MacLeod, and McCarty discovered that the biochemical nature of the transforming principle was _______

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

• Protein
• RNA
• DNA
• Lipid
Correct Option: C  [ DNA ]

Remark: They identified DNA as the genetic material causing transformation.

Digestion with _______ inhibited transformation, suggesting that the DNA caused the transformation.

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

• Proteases
• RNases
• DNases
• Lipases
Correct Option: C  [ DNases ]

Remark: Only DNase treatment stopped transformation, proving DNA was the agent.

The unequivocal proof that DNA is the genetic material came from the experiments of _______

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

• Griffith
• Avery et al.
• Hershey and Chase
• Watson and Crick
Correct Option: C  [ Hershey and Chase ]

Remark: Hershey and Chase provided the final proof using bacteriophages.

Hershey and Chase worked with _______

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

• Bacteria
• Fungi
• Bacteriophages
• Plants
Correct Option: C  [ Bacteriophages ]

Remark: They used viruses that infect bacteria (bacteriophages).

Hershey and Chase grew viruses in the presence of radioactive _______ to label protein.

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

• Phosphorus
• Sulfur
• Nitrogen
• Carbon
Correct Option: B  [ Sulfur ]

Remark: Radioactive Sulfur (S35) labels proteins because they contain sulfur.

Radioactive _______ was used to label DNA in the Hershey-Chase experiment.

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

• Sulfur
• Phosphorus
• Nitrogen
• Oxygen
Correct Option: B  [ Phosphorus ]

Remark: Radioactive Phosphorus (P32) labels DNA because it contains phosphates.

Bacteria which were infected with viruses that had radioactive DNA were _______

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

• Radioactive
• Non-radioactive
• Dead
• Mutated
Correct Option: A  [ Radioactive ]

Remark: The radioactive DNA entered the bacteria, making them radioactive.

The first genetic material to evolve was likely _______

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

• DNA
• RNA
• Protein
• Lipid
Correct Option: B  [ RNA ]

Remark: The RNA World hypothesis suggests RNA was the first genetic material.

2' OH group present at every nucleotide in RNA is a _______ group.

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

• Stable
• Reactive
• Inert
• Acidic
Correct Option: B  [ Reactive ]

Remark: The 2' OH group makes RNA labile and reactive.

DNA is chemically _______ reactive and structurally more stable when compared to RNA.

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

• More
• Less
• Equally
• Not
Correct Option: B  [ Less ]

Remark: DNA is less reactive and thus more stable than RNA.