Question

1. Incubating a competent strain of Escherichia coli with DNA in the form of a plasmid could lead to:

Group of answer choices

A. Transformation

B. Conjugation

C. Transduction

D. Vertical gene transfer

2. During DNA replication the lagging strand is synthesized:

Group of answer choices

A. Continuously

B. In Okazaki fragments

C. In the same direction as the advancing replication fork

D. From 3' to 5'

3. Which enzyme is responsible for linking Okazaki fragments in a newly created strand of DNA?

Group of answer choices

A. DNA ligase

B. DNA gyrase

C. DNA polymerase

D. Helicase

Answer 1

Answer 1:

Bacterial cells can acquire new genes via conjugation, transformation, or transduction. Conjugation occurs via a sex tube between two bacterial cells. Transformation is the acquisition of DNA directly from the medium. Transduction is the process by which viruses transfer genes from bacteria to another.

Thus, when we place competent bacterial cells with DNA (plasmid), then the bacterial cells would uptake this DNA and the process would be called transformation. Hence, the correct choice should be:

(a) Transformation.

Answer 2:

During DNA replication, one strand is synthesized continuously, called the leading strand. The other strand called lagging strand, is synthesized discontinously in the form of small fragments, called Okazaki fragments. Both leading and lagging strands are made in 5'-3' direction.

Hence, the correct choice should be:

(b) in Okazaki fragments.

Answer 3'

The Okazaki fragments are joined together by the enzyme:

(a) DNA ligase.