Biology Test Biology Microbiology and Biotechnology 3

Question 1

Which of the following is an example of horizontal gene transfer in bacteria?

Accepted Answer

Conjugation

Answer

Conjugation is a form of horizontal gene transfer where a plasmid or chromosomal DNA passes from a donor to a recipient bacterium through a pilus.

Question 2

What is the primary purpose of a vector in recombinant DNA technology?

Accepted Answer

To carry and replicate foreign DNA in a host organism

Answer

A vector (e.g., plasmid or viral vector) carries recombinant DNA into a host cell and allows it to replicate and be expressed.

Question 3

Viruses that infect bacteria are specifically called:

Accepted Answer

Bacteriophages

Answer

Bacteriophages (phages) are viruses that specifically infect bacterial cells and can follow lytic or lysogenic replication cycles.

Question 4

Which technique separates DNA fragments by size using an electric field?

Accepted Answer

Gel electrophoresis

Answer

Gel electrophoresis uses an electric field to migrate DNA through an agarose gel, with smaller fragments moving farther than larger ones.

Question 5

What is the main difference between gram-positive and gram-negative bacteria?

Accepted Answer

Gram-negative bacteria have an outer membrane absent in gram-positive bacteria

Answer

Gram-negative bacteria have an additional outer membrane containing lipopolysaccharides (LPS), which the Gram stain cannot penetrate, causing the cells to appear pink/red.

Biology Practice Test

Biology Practice Test

Biology Test Biology Microbiology and Biotechnology 3