Glucagon binds to the glucagon receptor, which interacts with a membrane-bound G protein, whose α subunit releases GDP and binds GTP. The α subunit then dissociates from the G protein and diffuses to a membrane-bound adenylyl cyclase which produces cAMP. In this scenario, name the

(1) transducer,

(2) effector,

(3) first messenger, and

(4) second messenger.

#Question id: 4639

#Unit 11. Evolution and Behavior

If the HMS Beagle had completely bypassed the Galapagos Islands, Darwin would have had a much poorer understanding of the

#Question id: 1382

#Unit 4. Cell Communication and Cell Signaling

Following statements are regarding to cell-cell and cell–extracellular matrix junctions and their adhesion molecules.

A. Adherens junctions and desmosomes are integrin-containing anchoring junctions that bind the membranes of adjacent cells, giving strength and rigidity to the entire tissue.

B. Hemidesmosomes are cadherin-containing anchoring junctions that attach cells to elements of the underlying extracellular matrix.

C. Integrins are a large family of αβ heterodimeric cell-surface proteins that mediate both cell-cell and cell-matrix adhesions and inside-out and outside-in signaling in numerous tissues.

D. Tight junctions block the diffusion of proteins and some lipids in the plane of the plasma membrane, contributing to the polarity of epithelial cells. They also limit and regulate the extracellular (paracellular) flow of water and solutes from one side of the epithelium to the other.

Which of the following statements are incorrect?

#Question id: 13181

#Unit 10. Ecological Principles

#Question id: 31025

#Unit 4. Cell Communication and Cell Signaling

#Question id: 11964

#Unit 7. System Physiology – Animal