Genes for which of the following functions would be constitutively expressed in a bacterial cell?

A retrovirus must have which of the following enzymes?

An inducer ligand binds to a repressor and causes it to fall off the operator DNA,permitting transcription of an operon. What will happen to the transcription ofstructural genes in each of the following scenarios? 1. If the repressor is mutated so that it cannot bind to the inducer ligand but can bind to the DNA.a. no transcription; b. constitutive transcription 2. The repressor is mutated so that it cannot bind to the DNA but can bind to theinducer ligand.a. no transcription; b. constitutive transcription. 3. The operator is mutated so that it cannot bind to the repressor.a. no transcription; b. constitutive transcription.

The virions (viral particles) of all animal viruses contain _______.

List key events that happen in the infected cell during the “eclipse” time of viralinfection (0.5 point for each blank).A. AttachmentB.___________________________________________________________C.___________________________________________________________D. Synthesis of viral ___________________and ____________________E. Replication of viral ___________________________________________F.____________________________________________________________F. Release of mature progeny virions

The stop codon UAG signals the DNA polymerase to stop replicating the chromosome.

Describe two mechanisms used by bacteria to defend DNAs from invading bacterialphages. (Required for only graduate students. Extra credit for undergrads.) Reasonable details are required for full credits. (2 points)

Sigma (σ) factors are the proteins that guide RNA polymerase to initiate transcription of genes.

In order to detect Coronavirus RNA by real-time PCR, the viral RNA needs to be converted into cDNA.

A lithotroph would be able to use ____ as a source of electrons?