The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.

Which of the five common ancestors, labeled V—Z, has given rise to the greatest number of species, both extant and extinct?

TLS Online TPP Program

#Question id: 14969

#Unit 2. Cellular Organization

 A new drug is developed that targets and binds to the lipid A portion of LPS from Gram negative bacterial cells. This drug shows a high degree of activity and binding in a test tube setting against purified lipid A. Based on this information,

TLS Online TPP Program

#Question id: 14970

#Unit 2. Cellular Organization

A research lab is trying to produce new antibiotics. They come up with drugs that detach the hydrophilic heads from the phospholipids in plasma membranes. This drug

TLS Online TPP Program

#Question id: 14971

#Unit 2. Cellular Organization

Bacillus and Clostridium are medically relevant groups of bacteria that characteristically stain 

TLS Online TPP Program

#Question id: 14972

#Unit 2. Cellular Organization

Although O side chains are readily recognized by host antibodies, gram negative bacteria may thwart host defenses by 

TLS Online TPP Program

#Question id: 14976

#Unit 2. Cellular Organization

Plasmids are not required for host growth and reproduction, although they may carry genes that give their bacterial host a selective advantage. Plasmid genes can render  bacteria 

1. Drug-resistant 

2. Give new metabolic abilities 

3. Make them pathogenic

Which among the following combinations is correct?

TLS Online TPP Program

#Question id: 14977

#Unit 2. Cellular Organization

Careful electron microscopic studies often have shown the nucleoids are present in contact. Thus bacterial DNA is attached to