MMSC436 PollEv Questions

Which of the following statements about enzymatic reactions is true? a. NADH has absorbance maxima at 340 and 366 nm b. Enzyme concentration must be in excess to achieve zero-order kinetics c. Rate is proportional to substrate concentration in a zero-order reaction d. Accumulation of the product increases the reaction rate

a

Which of the following statements about enzymes is true? a. Apoenzyme + prosthetic group = holoenzyme b. A coenzyme is an inorganic molecule required for activity c. Cofactors are as tightly bound to the enzyme as prosthetic groups d. All enzymes have optimal activity at pH=7

a

A 10-year-old girl visits her pediatrician with the complaint of bone pain. Following enzyme studies, these results were obtained: ALP 3.5x higher than the upper reference limit, NTP normal. These results are consistent with a diagnosis of: a. Hepatobiliary disease b. Normal bone growth c. Viral hepatitis d. Bone cancer

b

A hydrolase enzyme important during digestion that catalyzes the hydrolysis of starches while food is still in the mouth is: a. Lipase b. Lactate dehydrogenase c. S-type amylase d. P-type amylase

b

A type of detector used in GC that is universal in its detection of compounds but has low sensitivity compared with other detectors is a ________ detector. a. Flame ionization b. Thermal conductance c. Electron capture

b

At what point does the addition of more substrate NOT affect the rate of an enzyme reaction? a. At low substrate concentration b. At high substrate concentration c. Mediate substrate concentration to Km d. At substrate concentration equal to Km

b

For the reaction X --> Y, there are two catalysts. Catalyst I has activation energy of 1000 calories per mol. Catalyst II has activation energy of 2000 calories per mol. Which statement below is true? a. Catalyst II is more efficient b. Catalyst I is more efficient c. Both

b

The type of separation mechanism for chromatography that involves, as on example, use of immunologic principles is ______ chromatography. a. Ion exchange b. Affinity c. Hydrophobic d. Size exclusion

b

Which of the following statements concerning chromatography is correct? a. High performance liquid chromatography involves the use of support particles coated on a piece of glass or paper b. In affinity chromatography, a hormone can bind to its receptor that is coated on glass or resin beads c. Ion-exchange chromatography uses the principle that particles compete or binding sites in the stationary phase

b

Which one of the following optical techniques is not considered an emission technique? a. Phosphorimetry b. Nephelometry c. Luminometry d. Fluorometry

b

Which one of the following wavelengths is within the "near" ultraviolet region of the electromagnetic spectrum? a. 450nm b. 320nm c. 540nm d. 590nm

b

The increase in the level of serum enzymes used to detect cholestatic liver disease is caused mainly by: a. Enzyme release from dead cells b. Leakage from cells with altered membrane permeability c. Decreased perfusion of the tissue d. Increased production and secretion by cells

d

What is the most important catalytic feature of an enzyme? a. Increase in the free energy change b. Alteration of the reaction equilibrium c. Stabilization of the substrate d. Stabilization of the transition state

d

Which component of a generic spectrophotometer isolates radiant energy of a specific wavelength (spectral isolation) and excludes that of other wavelengths? a. Monochromator b. Entrance slit c. Cuvet d. Light source

a

A DNA polymerase enzyme can form a complex with either the substrate (ES) or the inhibitor (EI), but not both. This type of inhibition is... a. Competitive b. Non-competitive c. Mixed

a

A molecule is said to fluoresce when it absorbs light at one wavelength and emits light of: a. A lower energy b. A shorter wavelength c. A higher energy d. The same wavelength

a

A particular enzyme is usually assayed at 30C. if the temperature setting of the instrument is incorrectly set at 37C, what effect would this have on enzyme activity and thus the final result be? a. Enzyme activity would be higher at 37C b. Enzyme activity would be unchanged c. Enzyme activity would be approximately half d. Enzyme activity would be lower

a

In order for a drug to function as a good competitive inhibitor: a. It must bind to the active site better than the native substrate b. It must bind to the active site with less affinity than the native substrate c. The turn over number, Kcat, must be greater than that of the native substrate d. The Vmax for the drug must be greater than that of the native substrate

a

True or False? The type of GLC detector best used for detecting and measuring the concentration of pesticides in patient samples is electron captures 🡪 most sensitive a. True b. False

a

Activators that are required for normal CK activity include: a. Pyroxidal phosphate b. Magnesium, manganese, and colbalt c. Magnesium only d. NAD and NADH

c

In spectrophotometric determinations, which of the following is the formula for calculating the absorbance of a solution? a. (molar absorptivity * length of light path)/concentration in mol/L b. (molar absorptivity * concentration in g/dL)/length of light path c. (molar absorptivity * length of light path) * concentration in mol/L

c

Which of the following statements concerning lipase is incorrect? a. Lipase is localized partly in cells of the pancreas b. Following an acute attack of pancreatitis, lipase activity increases within hours c. Lipase is a small enzyme that can be detected in urine d. Lipase is considered to be in the hydrolase class of enzymes

c

Derivatisation of a sample in gas chromatography is carried out to a. Reduce polarity of the analytes b. Increase the detector response c. Increase volatility of the analytes d. All of the choices are correct

d

HIV protease is an enzyme that catalyzes the conversion of the AIDS virus polyprotein to functional proteins. What is the most important catalytic feature of such an enzyme? a. Increase in the free energy change b. Alteration of the reaction equilibrium c. Stabilization of the substrate d. Stabilization of the transition state e. Stabilization of the product

d

Heart tissue contains which of the following CK isoenzymes? a. MM only b. MB only c. BB only d. MM and MB

d

In a fluorometric measurement, the difference between the maximum wavelength of the excitation light and the maximum wavelength of the emitted fluorescence light is a constant referred to as: a. Beer law b. Chemiluminescence c. Polarization d. The Stokes shift

d

Isoenzymes are: a. Useful in clinical diagnoses b. Are observed in the enzyme, lactate dehydrogenase c. Enzymes which catalyze same chemical reaction but differ in their physical or chemical properties d. Are only observed in disease state e. A, B, and C are correct

e