Fig. 1 shows a graph of the blood alcohol concentration of one person after they stopped drinking alcohol at a party. The person had not eaten for several h...
Question 1 Report
Fig. 1 shows a graph of the blood alcohol concentration of one person after they stopped drinking alcohol at a party. The person had not eaten for several hours before drinking. Blood alcohol concentration was measured in mg per 100 cm3 of blood. The graph can help explain why a person may still be affected by alcohol after they stop drinking.
(a) Describe the pattern shown by the graph during the four hours. [3]
(b) Calculate the decrease in blood alcohol concentration during the first two hours. [2]
(c) Explain why the alcohol concentration in the blood falls after the person stops drinking. [4]
(d) State one reason why a different person might produce a different graph after drinking the same amount of alcohol. [1]
(e) Complete the sentences.
Alcohol is a depressant, so it can reduce coordination and slow a person's __________. This can affect safe __________. [2]
Answer Details
(a) Blood alcohol concentration decreases as time after drinking stopped increases [1]. It falls from 100 mg per 100 cm3 at 0 hours to about 31 mg per 100 cm3 at 4 hours [1]. The fall is steepest during the first hour and becomes less steep later [1].
(b) Read the concentration at 0 hours and at 2 hours from the graph:
\[100 - 61 = 39\]
The decrease is 39 mg per 100 cm3 [2].
(c) Alcohol is absorbed from the gut into the blood after drinking [1]. Once drinking stops, no further alcohol, or much less alcohol, enters the blood from the gut [1]. The liver breaks down, or metabolises, alcohol [1]. Therefore alcohol is removed from the blood and its concentration falls [1].
(d) A different graph could result from a different body mass, sex, amount of food eaten, liver function/tolerance, or rate of drinking. Any one [1]. These factors affect absorption, distribution, or breakdown of alcohol.
(e) Alcohol can slow a person's reactions or reaction time [1]. This can affect safe driving or operating machinery [1].
Exam reminder: when describing a graph, include the overall trend, quoted data with units, and a feature of the rate of change.
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