A 26-year-old construction worker is brought to the emergency room with a change in mental status after working a 10-hour shift on a hot summer day (average outside temperature was 97°F). The man had been sweating profusely during the day but did not drink fluids. He has a fever of 102°F, heart rate of 140 beats/min, and blood pressure of 100/55 mm Hg in the supine position. On examination, he has no perspiration, appears to have dry mucous membranes, and is poorly oriented to person, place, and time. Assuming that his kidneys were normal yesterday, which of the following sets of hormone levels describes his condition, compared with normal?

#Question id: 627

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following is correct ‘Dixon Plot’ for competitive inhibition for enzymes 

#Question id: 626

#Unit 1. Molecules and their Interaction Relevant to Biology

A metabolic pathway proceeds according to the scheme, R -> S -> T -> U -> V -> W.  A regulatory enzyme, X, catalyzes the first reaction in the pathway.  Which of the following is most likely correct for this pathway?

#Question id: 625

#Unit 1. Molecules and their Interaction Relevant to Biology

For enzymes in which the slowest (rate-limiting) step is the reaction Km becomes equivalent to:

#Question id: 624

#Unit 1. Molecules and their Interaction Relevant to Biology

The following data were obtained in a study of an enzyme known to follow Michaelis-Menten kinetics: The Km for this enzyme is approximately:

#Question id: 623

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of these statements about enzyme-catalyzed reactions is false?

#Question id: 622

#Unit 1. Molecules and their Interaction Relevant to Biology

An enzyme-catalyzed reaction was carried out with the substrate concentration initially a thousand times greater than the Km for that substrate.  After 9 minutes, 1% of the substrate had been converted to product, and the amount of product formed in the reaction mixture was 12 micromol.  If, in a separate experiment, one-third as much enzyme and twice as much substrate had been combined, how long would it take for the same amount (12 micromol) of product to be formed?