Textbook Chapter 7 Bacteriophage T7

Question 1

What are the three phases that a linear double stranded genome of bacteriophage T7?

Answer 1

1. first 850 bp enter spontaneously via the phage tail upon binding of the phage to the cell
2. the next 7 kb of DNA are pulled into the cell during transcription by cellular RNA polymerase
3. the final 32 kb are pulled into the cell during transcription by the phage T7 RNA polymerase

Question 2

Class I (early) genes are transcribed by what and what do they include?

Answer 2

transcribed by cellular RNA polymerase and include the gene coding for phage T7 RNA polymerase

Question 3

a terminator of transcription, TE, does what?

Answer 3

releases the host cell polymerase at the end of the class 1 region

Question 4

Class II (middle) genes are transcribed by and what do they include?

Answer 4

also transcribed by the phage T7 RNA polymerase at the end of the class II region

Question 5

a terminator of transcription T (omega?) releases what?

Answer 5

the T7 polymerases at the end of the class II region

Question 6

Class III (late) genes are also transcribed by the T7 polymerase and include genes coding for what?

Answer 6

structural phage proteins and proteins involved in release of progeny phage

Question 7

T7 DNA replication begins where?

Answer 7

at the first transcription initiation sites for T7 RNA polymerase and is mediated by RNA primers made by T7 RNA polymerase

Question 8

Linear concatemers of T7 DNA are formed when?

Answer 8

during DNA replication, probably by recombination via a terminal direct repeat sequence

Question 9

DNA concatemers are cleaved within what?

Answer 9

the terminal repeats in a reaction dependent on transcription by T7 RNA polymerase and are simultaneously packaged in phage proheads, which mature by shedding scaffolding proteins