1. There are viruses, called bacteriophage, that infectbacterial cells. Following viral entry, the cell begins tosynthesize viral DNA and viral proteins, leading to the productionof mature virus and the death of the bacterial cell. During thecourse of viral infection, transcription of bacterial genes isturned off so that transcription of viral genes predominates. Whichof the following is the most likely explanation for how the virusmanages to shift transcription from bacterial genes to its owngenes?
a. it synthesizes a viral RNA polymerase that recognizes onlyviral promoters
b. it synthesizes a viral DNA polymerase that recognizes onlyviral origins
c. it synthesizes a viral sigma subunit that directs thebacterial RNA polymerase to viral promoters
d. it has special viral ribosomes that only translate viralproteins
2. Unlike bacterial transcripts, eukaryotic RNA transcripts arechemically modified because:
a. Chemical groups help protect the mRNAs from degradation inthe eukaryotic cytoplasm, bacterial mRNAs are not degraded
b. Chemical groups facilitate the transport of eukaryotic RNAsfrom the nucleus to the cytoplasm, bacterial RNAs are synthesizedin the cytoplasm
c. Eukaryotic RNA polymerases cannot transcribe genes unlessthey are chemically modified, bacterial RNA polymerases transcribeunmodified genes
d. Transcripts in eukaryotic cells contain non coding regionsthat must be removed, bacterial transcripts contain only codingsequence
e. b and d
3. Termination of transcription in both E. coli and eukaryoticcells occurs because
a. there is a termination signal in the DNA following the genesequence.
b. there is a hairpin structure followed by a string of U
