Lecture 3

Question 1

What are tumor viruses?

Answer 1

tumor viruses are viruses that can cause cancer

Question 2

what did Peyton Rous do?

Answer 2

famous for his chicken sarcoma virus experiment

Question 3

what happened in the experiment involving avian tumor viruses?

Answer 3

1. chicken with sarcoma
2. sarcoma broken down into pieces
3. it was filtered thru fine pores
4. filtrate was collected
5. injected into chicken
6. chicken developed sarcoma

Question 4

what does gross polyoma do?

Answer 4

it can transform cells

Question 5

RNA tumor virus

Answer 5

tumor virus that has RNA genome

Question 6

retroviruses

Answer 6

RNA virus that replicates by reverse transcription using reverse transcriptase

Question 7

retroviruses with simple genomes

Answer 7

encodes viral structure proteins

Question 8

retroviruses with complex genomes

Answer 8

can encode regulators for gene expression

Question 9

what does the retrovirus viron contain?

Answer 9

envelope (host membrane), envelope proteins, capsid proteins, viral RNA (2 subunits), reverse transcriptase

Question 10

part of viral genome that codes for capsid proteins

Answer 10

gag

Question 11

part of viral genome that codes for envelope proteins

Answer 11

env

Question 12

part of viral genome that codes for reverse transcriptase

Answer 12

pol

Question 13

virus life cycle

Answer 13

1. viral genome has gag pol env
2. enters cell and sheds capsid
3. uses reverse transcriptase to make RNA and DNA hybrid
4. uses RT again to make dsDNA in cytosol
5. DNA incorporated into host genome using RT acting as integrase
6. uses hot genome

Question 14

what control elements do retroviruses generate during reverse transcription to control gene expression?

Answer 14

LTRs or long terminal repeats; gives the virus gene high level, signal independent gene expression