Fermentation occurs in both aerobic and anaerobic conditions, producing 2 ATP. It involves glycolysis and the conversion of pyruvate to lactic acid or ethyl alcohol. NAD+ is crucial for glycolysis, and its regeneration is essential for continued ATP production. Alcoholic fermentation, used in brewing and baking, involves converting pyruvate to ethanol and CO2. Lactic acid fermentation, occurring in muscles during intense exercise, leads to lactate accumulation and muscle fatigue.

What is the primary role of fermentation in cellular metabolism?

• To produce large amounts of ATP

• To store energy in the form of fats

• To regenerate NAD+ for glycolysis

• To convert glucose directly into ATP

Which of the following organisms is known for producing ethanol and CO2 during fermentation?

• Streptococcus

• Lactobacillus

• Saccharomyces cerevisiae

• Pseudomonas saccarophila

Where does fermentation occur within the cell?

• Cytoplasm

• Endoplasmic reticulum

• Mitochondria

• Nucleus

What is the first step in alcoholic fermentation?

• Reduction of acetaldehyde to ethanol

• Decarboxylation of pyruvate to acetaldehyde

• Conversion of glucose to pyruvate

• Oxidation of NADH to NAD+

Which enzyme is responsible for converting acetaldehyde to ethanol?

• Pyruvate decarboxylase

• Alcohol dehydrogenase

• Lactate dehydrogenase

• Hexokinase

In lactic acid fermentation, what is pyruvate directly reduced to?

• Lactate

• Carbon dioxide

• Acetaldehyde

• Ethanol

Why do human muscles switch to lactic acid fermentation during intense exercise?

• To store energy for later use

• To produce more ATP than aerobic respiration

• To compensate for the lack of oxygen

• To generate oxygen for the muscles