Electron Transport Chain
The electron transport chain, also known as the electron transport system, is a group of proteins that transfer electrons through a membrane within mitochondria to create a gradient of protons that drives adenosine triphosphate (ATP)synthesis. The cell uses ATP as an energy source for metabolic processes and cellular functions. ETC involves series of reactions that convert redox energy from NADH (nicotinamide adenine dinucleotide (NAD) + hydrogen (H)) and FADH2(flavin adenine dinucleotide (FAD)) oxidation into proton-motive force(PMF), which is then used to synthesize ATP through conformational changes in the ATP synthase complex, a process known as oxidative phosphorylation.
Metabolism
Picture a campfire. It keeps the body warm on a cold night and provides light. To ensure that the fire keeps burning, fuel needs to be added(pieces of wood in this case). When a small piece is added, the fire burns bright for a bit and then dies down unless more wood is added. But, if too many pieces are placed at a time, the fire escalates and burns for a longer time, without actually burning away all the pieces that have been added. Many of them, especially the larger chunks or damp pieces, remain unburnt.
Cellular Respiration
Cellular respiration is the cellular process involved in the generation of adenosine triphosphate (ATP) molecules from the organic nutritional source obtained from the diet. It is a universal process observed in all types of life forms. The glucose (chemical formula C6H12O6) molecules are the preferred raw material for cell respiration as it possesses a simple structure and is highly efficient in nature.
State and describe the roles of the six classes of enzymes, giving three examples each
Enzymes are essential proteins prepared and required by the cell to catalyze various metabolic reactions. They act by lowering the activation energy of the reaction so that the reactions that are otherwise impossible to take place or have a very slow rate in normal conditions could be carried out easily. As almost all the biochemical reactions in the living systems are catalyzed by enzymes, they are crucial for survival.
Enzymes are biomolecules that speed up or catalyze the reactions taking place in biological systems. There are more than 1000 different enzymes present in humans. They are classified into six different categories based on their roles.
1. Oxidoreductases: These enzymes catalyze the reactions that involve the oxidation-reduction process. They transfer the electron in the form of hydride ions or hydrogen from the donor molecules or reductants to the acceptor molecules or oxidants. Peroxidases, oxygenases, and hydroxylases belong to the group of oxidoreductases.
2. Transferases: The enzymes that catalyze the reactions involving the transfer of a functional group from one molecule to another are known as transferases. Most of the transfer requires cofactors to function. Transaminases, kinases, and acetyltransferases belong to this group.
3. Hydrolases: These group of enzymes carries out hydrolysis of the various complex biomolecules by cleaving the covalent bonds and transferring functional group to water. It is a digestive enzyme. Proteases, lipases, and nucleases are hydrolases.
4. Lyases: These are the enzymes that catalyze the addition or elimination reactions of a functional group. Lyases do not need water for split reactions. Decarboxylases, dehydratases, and aldolases belong to this group.
5. Isomerases: The enzymes responsible for intramolecular structural rearrangements are known as isomerases. They convert one isomer to the other by breaking and forming the bonds in the molecule in a way that molecule has the same molecular formula but different geometrical structure. Mutases, racemases, and epimerases belong to this group.
6. Ligases: The enzymes that join two molecules using ATP and forming a new bond between them are known as ligases. The two substrates involve are usually large biomolecules. They are also known as synthetase as they are involved in the process of synthesis. Amide synthetases, argininosuccinate synthetase, and peptide synthetases.
Translocases are also one group of enzymes that is responsible for the translocation of molecules or ions across the cell membrane.
Step by step
Solved in 3 steps
