General Meeting 3

A reaction occurs in which a molecule of ethanol (C₂H₅OH) is oxidized to form acetaldehyde (CH₃CHO) in the presence of NAD⁺, which is reduced to NADH. The standard reduction potential (E°) for the ethanol/acetaldehyde half-reaction is −0.20 V, and for the NAD⁺/NADH half-reaction it is −0.32 V.

Which of the following best describes the thermodynamics of this redox reaction?

• The reaction is spontaneous because NAD⁺ is reduced and ethanol is oxidized.

• The reaction is non-spontaneous because ethanol has a lower reduction potential than NAD⁺

• The reaction is spontaneous because the reduction potential of ethanol is greater than that of NAD⁺

• The reaction is non-spontaneous because the reduction potential difference between the two half-reactions is negative.

During intense exercise, the muscles produce large amounts of lactic acid as a byproduct of anaerobic glycolysis. In response to increased acidity in the blood, which of the following physiological mechanisms would most likely be activated to restore blood pH?

• Increased bicarbonate reabsorption by the kidneys

• Decreased respiratory rate

• Increased excretion of hydrogen ions by the liver

• Decreased heart rate to limit blood flow to muscles

Tags

NGSS.HS-LS1-3

During ventricular contraction, which of the following valves prevent backflow of blood from the ventricles into the atria?

• Pulmonary and aortic valves

• Mitral and tricuspid valves

• Tricuspid and pulmonary valves

• Aortic and mitral valves

Which of the following statements regarding enzyme kinetics is true?

• The Michaelis-Menten constant (Km) represents the substrate concentration at which the reaction rate is at its maximum.

• An enzyme's activity can be increased by raising the temperature, provided the temperature does not exceed the enzyme's optimal temperature.

• Competitive inhibitors increase the maximum velocity (Vmax) of the enzyme-catalyzed reaction.

• Non-competitive inhibitors increase the Km value of the enzyme for its substrate.

Which of the following best describes the concept of cognitive dissonance?

• The tendency to attribute others' behaviors to their character while attributing one’s own behaviors to situational factors.

• The process by which a person uses mental shortcuts to make judgments quickly and efficiently.

• The phenomenon where an individual becomes more confident in their beliefs after encountering contradictory evidence.

• The discomfort experienced when holding two conflicting beliefs or attitudes, leading to a change in one of them to reduce the discomfort.