7.2.1 Biotechnology: Reverse Transcriptase: A Tool Taken from Viruses

Question 1

Reverse transcriptase

Answer 1

• an enzyme that makes DNA from an RNA template
• can be used as a tool in biotechnology
• The central dogma of biology states that DNA directs the synthesis of RNA and RNA directs the synthesis of protein. Although the central dogma usually holds true, it sometimes does not, as in the case of retroviruses.

Question 2

Retroviruses

Answer 2

• depend on reverse transcriptase to propagate themselves within a host cell
• can make DNA from RNA using the enzyme
  reverse transcriptase. Two examples of retroviruses are
  the common cold and HIV.
• Beginning at the top of the diagram, HIV enters the cell and uses reverse transcriptase to make a DNA strand from its RNA.
• The synthesized DNA strand is then used as a template to make a complementary strand of DNA.
• The double-stranded DNA segment will then enter the nucleus of the host cell and integrate into the host chromosome. In the nucleus, RNA is transcribed from the viral DNA.
• After being translated by the cell, viral RNA directs the
  synthesis of viral protein, such as reverse transcriptase, and components of the viral coat. New viruses are then assembled and bud off of the host cell.

Question 3

HIV (Human Immunodeficiency Virus)

Answer 3

• the virus that causes AIDS, is a retrovirus that uses reverse transcriptase to multiply itself within a host cell.

Question 4

Which of the following is a retrovirus?

Answer 4

• Human immunodeficiency virus

Question 5

Reverse transcriptase is a(n)

Answer 5

• protein
• polymerase
• enzyme

Question 6

Reverse transcriptase catalyzes the production of __________ from the retrovirus.

Answer 6

• complementary DNA

Question 7

The key difference between a retrovirus and other viruses is that retroviruses are

Answer 7

• RNA-based, and use reverse transcriptase to form DNA which can integrate into the host genome