Question 1

Which of the following best describes the function of restriction endonucleases in molecular cloning?

Accepted Answer

They cleave DNA at specific recognition sequences, allowing for the creation of defined fragments.

Question 2

A plasmid is cut with EcoRI and run on an agarose gel. Compared to uncut plasmid, the linearized DNA will:

Accepted Answer

Run slower than supercoiled DNA because it is less compact.

Question 3

Which element in a cloning vector ensures that only bacteria containing the plasmid will grow on antibiotic media?

Accepted Answer

Ampicillin resistance gene (ampr)

Question 4

What is the primary difference between prokaryotic and eukaryotic genes regarding introns?

Accepted Answer

Prokaryotic genes are usually colinear and lack introns, while eukaryotic genes often contain introns.

Question 5

During transcription in eukaryotes, which of the following occurs first?

Accepted Answer

Binding of RNA polymerase to the promoter region

Question 6

Which of the following best defines an open reading frame (ORF)?

Accepted Answer

A continuous stretch of codons in mRNA that begins with a start codon and ends with a stop codon.

Question 7

If a mutation occurs in the promoter region of a gene, what is the most likely consequence?

Accepted Answer

No or little protein will be produced (LOF).

Question 8

Which of the following statements about introns and exons is correct?

Accepted Answer

Exons are coding regions that remain in mature mRNA, while introns are non-coding regions that are spliced out.

Question 9

Why do exons tend to be more conserved than introns across related species?

Accepted Answer

Exons are under negative selection because they encode functional proteins.

Question 10

Which of the following is a typical size range for exons in most organisms?

Accepted Answer

$$30-60$$ amino acids

Question 11

A gene contains three exons and two introns. After transcription and splicing, what will the mature mRNA contain?

Accepted Answer

Only exons, with introns removed

Question 12

Which of the following best explains why gene length varies so widely among different organisms?

Accepted Answer

Variation in the number and size of introns

Question 13

What is the consequence of alternative splicing if the reading frame is not maintained?

Accepted Answer

Production of unrelated proteins due to a shift in the reading frame

Question 14

How many possible reading frames are there in a single mRNA molecule?

Accepted Answer

$$3$$

Question 15

Which of the following is true about the organization of interrupted genes?

Accepted Answer

The positions of introns are usually conserved, but their lengths may vary greatly.

Question 16

A researcher wants to express a human protein in E. coli. Which of the following must be included in the cloning vector to ensure successful expression and selection?

Accepted Answer

A bacterial promoter, Shine/Dalgarno sequence, and antibiotic resistance gene

Question 17

Which of the following is a real-world application of recombinant DNA technology discussed in the materials?

Accepted Answer

Production of transgenic animals expressing fluorescent proteins

Question 18

If a DNA fragment is inserted into a plasmid at the MCS using EcoRI, what is the role of DNA ligase in this process?

Accepted Answer

It forms new phosphodiester bonds to join the DNA fragment and plasmid.

Question 19

Which of the following best describes the mature mRNA after splicing in eukaryotes?

Accepted Answer

It contains only exons and the 5' and 3' UTRs.

Molecular Cloning and Interrupted Genes: Structure, Function, and Variation

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