alleryStart learning →What range of ethanol tolerance is reported for yeast, depending on strain and conditions?
AAbout 1 percent to 5 percent
BAbout 5 percent to 21 percent
CAbout 21 percent to 40 percent
DAbout 40 percent to 70 percent
Answer & Solution
Correct answer: B. About 5 percent to 21 percent
1. Fermentation of pyruvic acid by yeast produces the ethanol found in alcoholic beverages.
2. Ethanol eventually becomes intolerable to the yeast making it.
3. Ethanol tolerance of yeast is variable, ranging from about 5 percent to 21 percent.
4. The range depends on the yeast strain and on environmental conditions.
5. The word about matters, since these are approximate bounds rather than exact limits.
6. Higher ranges would imply spirit-strength alcohol from fermentation alone, which the stated tolerance rules out.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 7 "Cellular Respiration", section 7.5 Metabolism without Oxygen_
Keep practising Cellular Respiration
Browse all Cellular Respiration questions for KCSE, or explore more Biology topics.
Related questions
Fill in the energy currency factsSplit the two electron carriersRoughly what free energy do the electrons carried by NADH hold as they enter the electron How is the rate of electron transport through the chain controlled?Besides being catabolized further, what else can the pyruvate produced by glycolysis becomWhich enzyme is described as the main controlled enzyme of glycolysis?What happens to glucose in a tissue where hexokinase has been inhibited?How does an allosteric effector change the behaviour of an enzyme?