Free WSET Wine Production Test 2 — Questions and Answers
Question 1: Glycolysis is part of both alcoholic and lactic acid fermentation cycles.
- TRUE (Correct answer)
- FALSE
Correct answer: TRUE
Glycolysis is the initial metabolic pathway that breaks down glucose into pyruvate. This process serves as the first stage for both alcoholic fermentation and lactic acid fermentation, as both pathways utilize pyruvate as their starting material. Therefore, glycolysis is a common and essential precursor to both anaerobic processes.
Question 2: Lactic acid fermentation occurs in muscle cells during very strenous kind of exercise such as sprinting.
- TRUE (Correct answer)
- FALSE
Correct answer: TRUE
During very strenuous exercise, such as sprinting, muscle cells may not receive enough oxygen for aerobic respiration. In these anaerobic conditions, muscles switch to lactic acid fermentation to regenerate NAD+ from NADH, allowing glycolysis to continue producing a small amount of ATP. This process results in the accumulation of lactic acid in the muscles.
Question 3: In Lactic Acid Fermentation, pyruvic acid is converted into a 2 - carbon molecule before producing lactic acid.
- TRUE
- FALSE (Correct answer)
Correct answer: FALSE
In lactic acid fermentation, pyruvic acid (pyruvate) is directly converted into lactic acid by the enzyme lactate dehydrogenase. Unlike alcoholic fermentation, there is no intermediate step involving the decarboxylation of pyruvic acid into a 2-carbon molecule. The conversion is a single-step reduction.
Question 4: There are ____ hydrogen atoms found in a molecule of glucose.
- Six
- Twelve (Correct answer)
- Eighteen
- Twenty
Correct answer: Twelve
The chemical formula for glucose is C₆H₁₂O₆. This formula explicitly indicates the number of atoms of each element present in one molecule of glucose. Therefore, a molecule of glucose contains twelve hydrogen atoms.
Question 5: 2 hydrogen atoms are accepted by NAD+ in the Alcoholic fermentation cycle.
- TRUE (Correct answer)
- FALSE
Correct answer: TRUE
During glycolysis, which precedes alcoholic fermentation, NAD+ acts as an electron acceptor. Specifically, it accepts two electrons and one proton (H+) from the oxidation of glyceraldehyde-3-phosphate, forming NADH and releasing another proton. This effectively means NAD+ is reduced by accepting components equivalent to two hydrogen atoms.
Question 6: Carbon Dioxide is produced between pyruvic acid and a(n) ____, in alcoholic fermentation.
- 2-Acetaldehyde (Correct answer)
- 3-Acetaldehyde
- Lactic Acid molecule
- Ethanol
Correct answer: 2-Acetaldehyde
In alcoholic fermentation, pyruvic acid, a 3-carbon molecule, first undergoes decarboxylation, releasing a molecule of carbon dioxide. This reaction produces a 2-carbon molecule called acetaldehyde. Acetaldehyde is then subsequently reduced to ethanol.
Question 7: There are 4 carbon atoms in each of the molecules of ethyl alcohol and lactic acid?
- TRUE
- FALSE (Correct answer)
Correct answer: FALSE
Ethyl alcohol (ethanol) has the chemical formula C₂H₅OH, indicating it contains two carbon atoms. Lactic acid has the chemical formula C₃H₆O₃, meaning it contains three carbon atoms. Therefore, the statement that both molecules contain four carbon atoms is incorrect.
Question 8: FADH is found in both alcoholic and lactic acid fermentation cycles.
- TRUE
- FALSE (Correct answer)
Correct answer: FALSE
FADH (or FADH₂) is a coenzyme primarily involved in the Krebs cycle and the electron transport chain, which are components of aerobic respiration. Both alcoholic and lactic acid fermentation are anaerobic processes that do not utilize FADH or FADH₂; their primary electron carrier is NAD+/NADH.
Question 9: What is the common name of Saccharomyces cerevisiae?
- Bacteria
- Mold
- Yeast (Correct answer)
- Algae
Correct answer: Yeast
Saccharomyces cerevisiae is a species of yeast, a single-celled microorganism classified as a fungus. It is widely known as baker's yeast or brewer's yeast due to its crucial role in baking and the production of alcoholic beverages like wine and beer.
Question 10: Alcoholic fermentation uses _____ cells such as Saccharomyces cerevisiae to make wine and beer.
- Animal
- Bacterial
- Fungus
- Yeast (Correct answer)
Correct answer: Yeast
Alcoholic fermentation is a biological process carried out by specific microorganisms, most notably yeast, such as Saccharomyces cerevisiae. These yeast cells convert sugars present in grape must or grain wort into ethanol (alcohol) and carbon dioxide, which are essential for making wine and beer.
Question 11: What is the source of the pyruvate used in lactic acid fermentation?
- Electron Transport Chain
- Glycolysis (Correct answer)
- Krebs CycleKrebs Cycle
- Citric Acid Cycle
Correct answer: Glycolysis
Pyruvate is the final product of glycolysis, the metabolic pathway that breaks down glucose. In the context of fermentation, this pyruvate then serves as the starting substrate for either lactic acid fermentation or alcoholic fermentation, depending on the organism and conditions.
Free WSET Wine Production Test 2
Glycolysis is part of both alcoholic and lactic acid fermentation cycles.