During Aerobic Respiration, Electrons Travel Downhill in Which Sequence?
At aerobic respiration, electrons travel downhill in a specific sequence from the outer membrane of mitochondria (in prokaryotes) or cytoplasm (in eukaryotes). Once inside, they move along an electron transport chain that pumps hydrogen ions across to form water and then into intermembrane space at cristae (foldings) of this inner membrane where they can be utilized by ATP synthase to turn ADP into ATP.
The energy released during this process is primarily used to power the cell’s functions, though some is also utilized for fueling chemical reactions that support other processes. This energy can be conserved as ATP, which then produces other molecules required for cellular functions.
Glucose serves as the main substrate for aerobic respiration, which occurs in most animals, plants, birds and humans alike. Through aerobic respiration, glucose molecules are broken down to release energy and produce carbon dioxide gas as waste product; it also converts into water and ATP.
Aerobic respiration involves four distinct processes: glycolysis, the link reaction, Krebs cycle and oxidative phosphorylation. Each stage breaks down different components of glucose into simpler units for easier absorption.
First, one molecule of glucose is split into two 3-carbon pyruvate molecules by an enzyme called hexokinase. This step makes the molecule more reactive so it can be further split in an enzyme-controlled reaction later.
Pyruvate molecules combine with oxygen to form three NADH and FADH2 compounds, serving as temporary electron acceptors for the citric acid cycle or Krebs cycle – the next stage in aerobic respiration.
This step liberates the energy stored in glucose’s bonds. This can be utilized for other catabolic metabolic reactions or stored as ATP for later use by other organisms.
Glycolysis is the initial stage in a series of metabolic pathways that create more complex molecules like fatty acids or proteins for use by the body for other purposes.
Catabolism is an essential catabolic metabolic process that requires oxygen for proper operation. Without adequate oxygen supply, fermentation will take place instead – an anaerobic reaction which releases less energy than aerobic respiration but may be preferred by some organisms since they don’t need to breathe oxygen for survival.
The next stage in glycolysis is called the link reaction, where one molecule of glucose is linked to another by an enzyme called acetyl-CoA. This molecule in turn links with another three molecules, and this cycle continues endlessly.
Each cycle of the Krebs cycle produces a net gain of CO2, 3 NADH and 1 FADH2. Additionally, it generates three more molecules of acetyl-CoA as well as one molecule of ATP.
This molecule of ATP is essential to catabolic metabolic reactions and can be stored in either the cytoplasm or mitochondria for later use. It then powers other enzyme-controlled processes or is converted into molecules like amino acids or fats.