Answer to Question 1
A
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Channels or pores within the cell membrane are made by proteins in the cell wall that allow the passage of small substances in or out of the cell. Specific channels have been identified for sodium, potassium, calcium, chloride, bicarbonate, and water; other channels may also exist. Some drugs are designed to affect certain channels specifically. For example, calcium channel blockers prevent the movement of calcium into a cell through calcium channels. Options B, C, and D are not known to have their own channels at this time.
Answer to Question 2
A
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The introduction of chyme or stretch to the large intestine slows stomach activity, known as the ileogastric reflex which explains why patients who are constipated have no appetite. The intestinalintestina l reflex is triggered by irritation of a section of the small intestine causing cessation of activity above that section. Peritoneointestinal reflex results from irritation of the peritoneum while renointestinal reflex results from irritation or swelling of the renal capsule.
Stable folding patterns in proteins
Sickle cell.
The offspring of the microchip—from computers to cell phones—offer access to vast information ...
Attachment and cell entry by HIV.
Activation and Clonal Selection of a Helper T Cell
The eukaryotic cell cycle.