Cell Bio Quiz 2

Which of the following is an advantage of multicellularity?

Greater mobility

Which adaptation specific to becoming multicellular compensates for the destabilizing effect of increased size? (Think carefully about answer choices!)

Both ECM and tight junctions

Liver cells respond to epinephrine by __________.

Breaking down glycogen.

Which of the following is a disadvantage of being a multicellular organism?

Decreased structural stability

ATP hydrolysis is highly _____ because it involves _____.

Exergonic; separation of negatively charged phosphate groups

Which of the following is an advantage of endocrine signaling?

It affects large numbers of cells.

Which of the following enzymes catalyzes phosphorylation of proteins using a phosphate group from ATP?

Kinases

Archeological evidence suggests that Neanderthals may have been aware of the medicinal properties of plants over 60,000 years ago. Imagine you are a modern-day ethnobotanist and have identified a compound from fossilized tree pollen that binds to the alpha subunit of the most common G-proteins. To test how the compound affects the activity of Gα, you treat liver cells with the compound alongside epinephrine. You observe that the cells fail to produce glucose. Which of the following could be how the compound acts?

None of the above

What is the second messenger in the receptor tyrosine kinase signaling pathway?

None of the above

"During embryonic development red blood cells begin to develop in patches called blood islands. The blood cells secrete growth factors that diffuse only to nearby cells, signaling differentiation into endothelial cells. The endothelial cells eventually form the linings of the blood vessels." The growth factor described in the passage is involved in what type of signaling?

Paracrine

ras, a small GTPase, hydrolyzes GTP slowly on its own, but its enzymatic activity is increased significantly in the presence of GTPase activating proteins (GAPs). Imagine you discovered a novel mutation that prevents GAP from binding to ras. This mutation would have the effect of:

The ras pathway results in proliferation. The GTPase activity counteracts this effect. So you have to figure out what would happen if you inhibit the GAP that would normally accelerate the GTPase.

A major function of the epithelium in animals is to prevent entry of pathogens and toxins from the environment. Which of the following is common to all epithelial cells?

They are held together by tight junctions.

Which of the following is true of both GPCR signaling and steroid hormone signaling?

They may result from endocrine signals: True; any signaling molecule could be secreted into the bloodstream.

∆G°' for the hydrolysis of ATP is considered to be:

highly exergonic