BAT Alcohol Metabolism & Physiology 2 — Questions and Answers
Question 1: Which enzyme is primarily responsible for converting acetaldehyde to acetate during alcohol metabolism?
- Alcohol dehydrogenase
- Aldehyde dehydrogenase (Correct answer)
- Cytochrome P450 2E1
- Catalase
Correct answer: Aldehyde dehydrogenase
Aldehyde dehydrogenase (ALDH) converts the toxic intermediate acetaldehyde into acetate in the second step of alcohol metabolism.
Question 2: In the context of breath alcohol testing, the 'partition ratio' refers to the ratio of alcohol concentration in:
- Blood to urine
- Alveolar air to arterial blood (Correct answer)
- Breath to venous blood
- Stomach fluid to blood
Correct answer: Alveolar air to arterial blood
The partition ratio (2100:1) describes how alcohol distributes between alveolar air and arterial blood at body temperature.
Question 3: A subject has a BrAC of 0.080 g/210L. Applying the standard 2100:1 partition ratio, the estimated blood alcohol concentration (BAC) would be approximately:
- 0.008 g/dL
- 0.080 g/dL (Correct answer)
- 0.800 g/dL
- 0.038 g/dL
Correct answer: 0.080 g/dL
Because the 2100:1 ratio is already built into breath test instruments, the BrAC reading is reported directly equivalent to BAC in g/dL.
Question 4: Which body compartment has the highest water content, making it the primary distribution space for alcohol?
- Adipose tissue
- Total body water (Correct answer)
- Plasma only
- Cerebrospinal fluid
Correct answer: Total body water
Alcohol is hydrophilic and distributes throughout total body water, which represents about 60% of body weight in males.
Question 5: What physiological factor explains why women generally reach higher BAC levels than men when consuming the same amount of alcohol per kilogram of body weight?
- Women metabolize alcohol faster
- Women have a lower proportion of total body water (Correct answer)
- Women have more ALDH enzyme activity
- Women absorb alcohol more slowly
Correct answer: Women have a lower proportion of total body water
Women have proportionally less total body water than men, so the same dose of alcohol is distributed in a smaller aqueous volume, yielding a higher concentration.
Question 6: The Widmark formula uses the variable 'r' to account for:
- Rate of alcohol elimination
- Individual body water distribution factor (Correct answer)
- Rate of gastric emptying
- Respiratory quotient
Correct answer: Individual body water distribution factor
The Widmark 'r' factor (also called the volume of distribution or Widmark factor) represents the fraction of body weight that is water available for alcohol distribution.
Question 7: During the post-absorptive phase, blood alcohol concentration typically changes at a rate consistent with:
- Second-order kinetics
- Zero-order kinetics (Correct answer)
- First-order kinetics
- Michaelis-Menten saturation kinetics only at low BAC
Correct answer: Zero-order kinetics
At typical drinking BAC levels, alcohol elimination follows zero-order kinetics, meaning a constant amount (not percentage) is eliminated per unit time.
BAT Alcohol Metabolism & Physiology 2
Which enzyme is primarily responsible for converting acetaldehyde to acetate during alcohol metabolism?