Molecular oxygen
Pyruvate is the result of glycolysis, the degradation of a molecule of glucose. In aerobic conditions (with O2 present), pyruvate is oxidized to H2O and CO2 via the citric acid cycle and oxidative phosphorylation to produce energy (ATP). In anaerobic conditions (low levels of O2), pyruvate metabolism goes in two directions: in yeasts, an alcoholic fermentation takes place (with the production of two CO2 molecules + two molecules of ethanol); while in muscle, homolactic fermentation occurs (with the result of 2 molecules of lactate).
Yes, during lactic acid fermentation, glucose is broken down into lactic acid to generate energy in the absence of oxygen. This process occurs in muscle cells during strenuous exercise when oxygen supply is limited.
Oxygen deprivation in fetuses can be determined by monitoring the fetal heart rate patterns using electronic fetal monitoring. This can be done during labor and delivery to assess the oxygen supply to the fetus. Other signs such as decreased fetal activity or low oxygen levels in the mother's blood may also indicate oxygen deprivation in the fetus.
There are three carbon atoms in a molecule of pyruvate.
In oxygen deprivation, muscle cells convert pyruvate into lactate through anaerobic glycolysis. This conversion allows the cells to regenerate NAD+ from NADH, enabling glycolysis to continue and produce ATP without oxygen. This helps sustain energy production in the absence of sufficient oxygen supply.
The lactate is taken to the liver and converted back to pyruvate.
Lactic acid fermentation converts pyruvate into lactic acid in the absence of oxygen. This process occurs in muscle cells during strenuous exercise when oxygen levels are low, leading to the buildup of lactic acid and temporary muscle fatigue.
Muscles can generate energy through anaerobic pathways, such as glycolysis, which can produce ATP without the need for oxygen. During low oxygen levels, glycolysis helps break down glucose to provide energy for muscle contraction. However, this process can lead to the accumulation of lactic acid and fatigue.
The brain and the heart are the two organs most sensitive to oxygen deprivation. The brain relies heavily on a constant supply of oxygen to function properly, and even a short period of oxygen deprivation can lead to brain damage. Similarly, the heart requires a continuous oxygen supply to maintain its pumping function, and oxygen deprivation can lead to heart muscle damage or even a heart attack.
When the heart muscle is deprived of oxygen, it can lead to a condition called ischemia, which can result in chest pain (angina) or a heart attack (myocardial infarction). This oxygen deprivation can be caused by blockages in the coronary arteries, leading to reduced blood flow to the heart muscle.
The organs most sensitive to deprivation of oxygen are the heart and the brain.
When oxygen is available, pyruvate enters the mitochondria to undergo aerobic respiration. In the mitochondria, pyruvate is converted into acetyl-CoA in the presence of oxygen, leading to the production of ATP through the Krebs cycle and oxidative phosphorylation.
Molecular oxygen
Glycolysis is the only step in cell respiration that is not oxygen-dependent. It takes place in the cytoplasm and does not require oxygen to convert glucose into pyruvate, generating a small amount of ATP in the process.
Pyruvate is the result of glycolysis, the degradation of a molecule of glucose. In aerobic conditions (with O2 present), pyruvate is oxidized to H2O and CO2 via the citric acid cycle and oxidative phosphorylation to produce energy (ATP). In anaerobic conditions (low levels of O2), pyruvate metabolism goes in two directions: in yeasts, an alcoholic fermentation takes place (with the production of two CO2 molecules + two molecules of ethanol); while in muscle, homolactic fermentation occurs (with the result of 2 molecules of lactate).
lactate