Answer the following question given this paragraph: produced in cells located in the stomach wall. When food enters the stomach after a period of fasting, pepsinogen is converted to its active formpepsinin a series of steps initiated by the drop in pH. Pepsin catalyzes the hydrolysis of peptide linkages within protein molecules. It has a fairly broad specificity but acts preferentially on linkages involving the aromatic amino acids tryptophan, tyrosine, and phenylalanine, as well as methionine and leucine. Protein digestion is completed in the small intestine. Pancreatic juice, carried from the pancreas via the pancreatic duct, contains inactive enzymes such as trypsinogen and chymotrypsinogen. They are activated in the small intestine as follows (Figure 20.7 "Activation of Some Pancreatic Enzymes in the Small Intestine"): The intestinal mucosal cells secrete the proteolytic enzyme enteropeptidase, which converts trypsinogen to trypsin; trypsin then activates chymotrypsinogen to chymotrypsin (and also completes the activation of trypsinogen). Both of these active enzymes catalyze the hydrolysis of peptide bonds in protein chains. Chymotrypsin preferentially attacks peptide bonds involving the carboxyl groups of the aromatic amino acids (phenylalanine, tryptophan, and tyrosine). Trypsin attacks peptide bonds involving the carboxyl groups of the basic amino acids (lysine and arginine). Pancreatic juice also contains procarboxypeptidase, which is cleaved by trypsin to carboxypeptidase. The latter is an enzyme that catalyzes the hydrolysis of peptide linkages at the free carboxyl end of the peptide chain, resulting in the stepwise liberation of free amino acids from the carboxyl end of the polypeptide. Figure 20.7 Activation of Some Pancreatic Enzymes in the Small Intestine. Q: When food enters the stomach after a period of fasting, a drop in what initiates the conversion of pepsinogen to pepsin? Choices: - calcium - white blood cells - acid - ph A:
ph
(Question)
Answer the following question given this paragraph: The kidneys filter blood and form urine. They are part of the urinary system, which also includes the ureters, bladder, and urethra. Q: What organs filter blood and form urine? Choices: - the appendix - the spleen - the liver - the kidneys A:
(Answer)
the kidneys
Ques: Answer the following question given this paragraph: The reaction of an alkyl halide with an inorganic hydroxide base at elevated temperature produces an alcohol. The molecular reaction to produce methanol from iodomethane and sodium hydroxide is shown below. Q: The reaction of an alkyl halide with an inorganic hydroxide base at elevated temperature produces what? Choices: - blood - methane - yeast - an alcohol A:
Ans: an alcohol
(Q).
Answer the following question given this paragraph: Cell division is just one stage of the cell cycle. The cell cycle includes all of the stages in the life of a cell. The cell cycle is more complex in eukaryotic than prokaryotic cells. Q: What stages in the life of a cell does the cell cycle include? Choices: - adult stages - intermediate stages - both - all A:
(A).
all
Ques:Answer the following question given this paragraph: Q: What returns blood from capillaries to an atrium? Choices: - the lymph system - arteries - the liver - veins A:

Ans:veins
Ques:Answer the following question given this paragraph: Osmotic pressure is important in biological systems because cell walls are semipermeable membranes. In particular, when a person is receiving intravenous (IV) fluids, the osmotic pressure of the fluid needs to be approximately the same as blood serum; otherwise bad things can happen. Figure 11.4 "Osmotic Pressure and Red Blood Cells" shows three red blood cells: Figure 11.4 "Osmotic Pressure and Red Blood Cells"a shows a healthy red blood cell. Figure 11.4 "Osmotic Pressure and Red Blood Cells"b shows a red blood cell that has been exposed to a lower concentration than normal blood serum (a socalled hypotonic solution); the cell has plumped up as solvent moves into the cell to dilute the solutes inside. Figure 11.4 "Osmotic Pressure and Red Blood Cells"c shows a red blood cell exposed to a higher concentration than normal blood serum (hypertonic); water leaves the red blood cell, so it collapses onto itself. Only when the solutions inside and outside the cell are the same (isotonic) will the red blood cell be able to do its job. Q: Osmotic pressure is important in biological systems because cell walls are what? Choices: - impassable - theonym membranes - variably membranes - semipermeable membranes A:

Ans:
semipermeable membranes