Week 4 - Quiz 3

which statement describes a virulent phage?

A virulent phage destroys bacteria.

True or False: A characteristic that is independently acquired by reversal or convergent evolution exhibits homology.

False

What is a prophage?

It is phage DNA that is integrated into bacterial DNA.

How do retroviruses differ from other RNA viruses?

Retroviruses have reverse transcriptase instead of RNA-dependent RNA polymerase

At what stage of a lytic infection are phage components put together to make new viruses?

assembly

what is the protein coat of a virus called?

capsid

The bacterium that causes botulism disease is harmless until it:

contains a certain prophage DNA

A taxon that includes all the descendants of an ancestor is called:

monophyletic

The organism labeled B in the accompanying figure (phylogenetic tree) is a common ancestor to:

organisms 2,3,4,5 and 6

A taxon that diverges earlier than the other taxa being considered in cladistic analysis is a(n):

outgroup

In the accompanying figure (phylogenetic tree), the taxon labeled II is:

paraphyletic

When faced with multiple possible cladograms, the criteria of ____ can be employed to pick the "best" hypothesis.

parsimony

What are the viruses that attack bacteria?

phages

The specificity of viruses to different types of cells is due to ____ sites on the host cell.

receptor

In the accompanying figure (phylogenetic tree) , the pair of organisms that have the most recent ancestor is:

2 and 3

True or False: Membership in a clade cannot be established by shared ancestral traits alone.

True

Which characteristic defines a virus?

Viruses cannot metabolize.

Which statement describes a temperate virus?

a temperate virus does not always destroy its host

At what stage of the lysogenic cycle would a prophage appear?

integration

What type of conversion occurs when a bacterium carrying viral genes takes on new, atypical characteristics?

lysogenic