Essential role in metabolism of carbohydrates, fats, and proteins.
The Correct Answer and Explanation is :
The essential role in metabolism of carbohydrates, fats, and proteins is played by enzymes and coenzymes, particularly NAD+ (Nicotinamide adenine dinucleotide) and FAD (Flavin adenine dinucleotide), as well as certain vitamins and minerals.
Explanation:
1. Carbohydrate Metabolism:
Carbohydrates are primarily metabolized for energy, with glucose being the most significant source. The process begins with glycolysis, where glucose is broken down into pyruvate, yielding ATP, the cell’s energy currency. From there, pyruvate is converted into acetyl-CoA, entering the citric acid cycle (Krebs cycle), where it undergoes oxidation to produce more ATP, NADH, and FADH2. These molecules then feed into the electron transport chain, where ATP is generated.
2. Fat Metabolism:
Fats, primarily in the form of triglycerides, undergo lipolysis, breaking down into fatty acids and glycerol. Fatty acids then enter the mitochondria where they are broken down through beta-oxidation into acetyl-CoA, which again enters the citric acid cycle for further energy production. The key enzymes in this pathway include lipase and acyl-CoA synthetase. Fatty acid metabolism is especially important during fasting or prolonged exercise when the body relies on fat stores for energy.
3. Protein Metabolism:
Proteins are broken down into amino acids by the process of proteolysis. Amino acids are then deaminated, and their carbon skeletons can be converted into acetyl-CoA, pyruvate, or other intermediates that enter the citric acid cycle. Some amino acids can also directly contribute to gluconeogenesis (the production of glucose from non-carbohydrate sources). The metabolism of amino acids is highly regulated to prevent excess buildup, as ammonia, a byproduct of deamination, is toxic.
Coenzymes like NAD+ and FAD play a crucial role in these processes by facilitating the transfer of electrons in oxidation-reduction reactions, allowing for the production of ATP, which is essential for maintaining cellular function and energy balance.