Molecular Basis of Inheritance Chapter-Wise Test 9

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which term describes a DNA sequence that can increase transcription levels when bound by proteins?

Promoter
Silencer
Enhancer
Operator
3

An enhancer is a DNA sequence that increases transcription levels when bound by transcription factors.

Which of the following statements about DNA replication is correct?

Helicase helps in unwinding the DNA double helix.
DNA polymerase synthesizes RNA primers.
Ligase breaks phosphodiester bonds in DNA.
Topoisomerase is responsible for adding nucleotides to the new strand.
1

Helicase unwinds the DNA double helix by breaking hydrogen bonds between the two strands.

Which of the following is NOT a post-transcriptional modification in eukaryotes?

5' capping
Polyadenylation
Splicing
Phosphorylation
4

Phosphorylation is a post-translational modification, not a post-transcriptional modification.

What is the primary function of enhancers in gene regulation?

Repress gene expression
Increase transcription efficiency
Bind directly to RNA polymerase
Terminate transcription
2

Enhancers increase transcription efficiency by binding to activator proteins and promoting RNA polymerase activity.

Which type of bond stabilizes the two strands of the DNA double helix?

Phosphodiester bonds
Hydrogen bonds
Ionic bonds
Covalent bonds
2

Hydrogen bonds between complementary base pairs stabilize the DNA double helix.

Which of the following statements about the lac operon is correct?

The lac operon is always turned on.
The lac operon is activated in the presence of lactose.
The lac operon is a repressible operon.
The lac operon does not require regulatory proteins.
2

The lac operon is activated in the presence of lactose, which inactivates the repressor and allows transcription.

Which feature of the genetic code allows multiple codons to encode the same amino acid?

Universality
Degeneracy
Non-overlapping nature
Triplet nature
2

Degeneracy means that multiple codons can specify the same amino acid, reducing the impact of mutations.

Which of the following correctly describes the role of a spliceosome?

It removes exons from pre-mRNA.
It removes introns from pre-mRNA.
It adds a poly-A tail to mRNA.
It assists in DNA replication.
2

The spliceosome removes introns from pre-mRNA and joins the exons together to form mature mRNA.

Which component of the ribosome catalyzes peptide bond formation during translation?

mRNA
tRNA
rRNA
Peptidyl transferase
4

Peptidyl transferase, an enzymatic function of rRNA, catalyzes peptide bond formation during translation.

Which of the following is NOT a function of RNA polymerase in eukaryotes?

Transcribing mRNA
Synthesizing DNA
Synthesizing rRNA
Catalyzing transcription
2

RNA polymerase is responsible for transcribing RNA from DNA but does not synthesize DNA itself.

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