Molecular Basis of Inheritance Chapter-Wise Test 7

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which of the following elements regulates the expression of genes by binding to specific sequences in DNA?

Enhancers
Introns
Exons
Poly-A tail
1

Enhancers are regulatory sequences that bind transcription factors to increase gene expression.

Which of the following is correct about RNA polymerase in eukaryotic transcription?

RNA polymerase I transcribes mRNA.
RNA polymerase II synthesizes rRNA.
RNA polymerase III transcribes tRNA.
RNA polymerase requires a primer to initiate transcription.
3

RNA polymerase III is responsible for transcribing **tRNA and some small RNAs** in eukaryotes.

Which of the following occurs first in eukaryotic gene expression?

Splicing
Polyadenylation
Transcription
Translation
3

Transcription is the first step in gene expression, producing pre-mRNA, which undergoes processing before translation.

Which of the following statements about aminoacyl-tRNA synthetase is correct?

It removes introns from mRNA.
It catalyzes the attachment of amino acids to tRNA.
It helps unwind DNA during replication.
It adds a poly-A tail to mRNA.
2

**Aminoacyl-tRNA synthetase attaches amino acids to their corresponding tRNAs**, enabling translation.

Which of the following statements about the genetic code is incorrect?

The genetic code is universal.
Each codon codes for only one amino acid.
The genetic code is overlapping.
The genetic code is degenerate.
3

The **genetic code is non-overlapping**, meaning codons are read sequentially without overlap.

Which of the following statements about the genetic code is true?

Each amino acid is coded by only one codon
It is non-overlapping and degenerate
The same codon codes for different amino acids
It has only one stop codon
2

The genetic code is non-overlapping and degenerate, meaning multiple codons can specify the same amino acid.

Which feature of the genetic code ensures that an amino acid can be coded by more than one codon?

Universality
Non-overlapping nature
Degeneracy
Specificity
3

Degeneracy of the genetic code means that multiple codons can specify the same amino acid.

Which of the following statements about ribosomes is incorrect?

Ribosomes are composed of rRNA and proteins.
Ribosomes function in protein synthesis.
Ribosomes are present in both prokaryotic and eukaryotic cells.
Ribosomes are membrane-bound organelles.
4

Ribosomes **are not membrane-bound organelles**; they are found freely in the cytoplasm or attached to the rough ER in eukaryotes.

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

Synthesizing RNA from a DNA template
Unwinding DNA strands
Catalyzing peptide bond formation
Initiating transcription at the promoter
3

RNA polymerase does not catalyze peptide bond formation; this function is performed by the ribosome.

Which of the following best describes the function of a transcriptional repressor?

Enhances gene expression
Prevents transcription by binding to the operator
Splices introns from pre-mRNA
Facilitates ribosome attachment to mRNA
2

A transcriptional repressor binds to the operator region of an operon to prevent RNA polymerase from initiating transcription.

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