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.

How many separate species, both extant and extinct, are depicted in this tree?

TLS Online TPP Program

#Question id: 2185

#Unit 2. Cellular Organization

Which amino acids would most likely reside in the membrane-anchoring domain of a membrane-embedded protein?

TLS Online TPP Program

#Question id: 2186

#Unit 2. Cellular Organization

Of the four classes of cellular macromolecules, which one is not a component of cell membranes?

TLS Online TPP Program

#Question id: 2187

#Unit 2. Cellular Organization

How do membranes function as a locus of biochemical reactions?

TLS Online TPP Program

#Question id: 2188

#Unit 2. Cellular Organization

The relative proportion (by weight) of lipid and protein in a membrane:

TLS Online TPP Program

#Question id: 2189

#Unit 2. Cellular Organization

Which of the following is not true of membrane phosphoglycerides?

TLS Online TPP Program

#Question id: 2190

#Unit 2. Cellular Organization

Membrane carbohydrates occur as: