The conversion of glucose to lactic acid is called
A. aerobic glucose breakdown.
B. anaerobic glucose breakdown.
C. aerobic glycogen breakdown.
D. anaerobic glycogen breakdown.
The correct answer and explanation is :
The correct answer is B. anaerobic glucose breakdown.
Explanation:
The process of converting glucose to lactic acid occurs under anaerobic conditions, which means in the absence of oxygen. This pathway is known as anaerobic glycolysis. To understand this better, it’s essential to consider the process of glucose metabolism and the role of oxygen in it.
Glycolysis is the initial step in the breakdown of glucose. It occurs in the cytoplasm of the cell and involves the conversion of one molecule of glucose (a six-carbon sugar) into two molecules of pyruvate (three-carbon molecules), producing a small amount of energy in the form of ATP. This process does not require oxygen, making it anaerobic.
When oxygen is available, the pyruvate produced from glycolysis enters the mitochondria, where it undergoes further oxidation in the aerobic process of cellular respiration, specifically the citric acid cycle (Krebs cycle) and oxidative phosphorylation. This process produces a large amount of ATP and does not produce lactic acid.
However, when oxygen is limited, as can occur during intense exercise or in anaerobic environments, the pyruvate cannot be fully oxidized. Instead, it is converted into lactic acid (lactate) through lactic acid fermentation. This conversion regenerates NAD+, which is essential for glycolysis to continue, allowing the cell to continue producing ATP in the absence of oxygen. The accumulation of lactic acid can lead to muscle fatigue and the “burn” sensation often felt during intense physical activity.
To recap:
- Anaerobic glucose breakdown refers to the conversion of glucose to lactic acid through glycolysis and fermentation when oxygen is unavailable.
- Aerobic glucose breakdown, in contrast, involves oxygen and leads to complete oxidation of glucose, producing water, carbon dioxide, and a much larger amount of ATP.
Thus, the correct term for the conversion of glucose to lactic acid is anaerobic glucose breakdown.