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 been least successful in terms of the percent of its derived species that are extant?

#Question id: 2246

#Unit 2. Cellular Organization

Which of the following statements describe(s) the typical biomembrane?

a. It may include different types of lipid molecules.

b. The lipid molecules in the membrane are attached to each other though covalent bonds.

c. All lipids and proteins in the biomembrane are equally mobile.

d. It contains a hydrophilic core.

e. It has a cytosolic face and an exoplasmic face.

#Question id: 2247

#Unit 2. Cellular Organization

When computing the osmotic pressure that must be placed across the membrane to stop the flow of water, what is the glucose osmotic equivalent of 1 M CaCl₂?

#Question id: 2248

#Unit 2. Cellular Organization

The movement of Na+ ions into an animal cell

a. has a positive ΔG value.                 

b. is energetically favorable.

c. is chemically favorable.                  

d. drives the export of Ca2+ in muscle cells.

#Question id: 2249

#Unit 2. Cellular Organization

In intestinal lumen epithelial cells, which of the following occurs by passive transport?

a. import of Na+ on the apical side    

b. export of Na+ on the basal side

c. import of glucose on the apical side           

d. export of glucose on the basal side

#Question id: 2250

#Unit 2. Cellular Organization

Which of the following is true about cystic fibrosis?

#Question id: 2251

#Unit 2. Cellular Organization

Differences between cotransport and active ion transport include