Metabolism: The sum of all chemical reactions within a living organism.
Ultimate Goal: To convert food into energy, build cellular components, and maintain homeostasis.
Catabolism: The breakdown of larger molecules into smaller units, releasing energy (e.g., cellular respiration).
Anabolism: The synthesis of larger molecules from smaller ones, requiring energy (e.g., protein synthesis).
Relationship: Catabolism provides the energy necessary for anabolic processes.
Molecule Used: ATP (Adenosine Triphosphate) is the principal energy carrier in cells.
Process to Store Energy: Phosphorylation of ADP (Adenosine Diphosphate) to ATP.
Process to Release Energy: Hydrolysis of ATP to ADP and inorganic phosphate.
Composition: Enzymes are typically proteins composed of amino acids.
Importance: They catalyze chemical reactions, increasing the reaction rates necessary for life processes.
Enzyme Name Indicators: Often end in "-ase" (e.g., lactase, protease), indicating their function.
Activation Energy: The minimum energy required to initiate a chemical reaction; enzymes lower this energy barrier.
Substrate: The specific reactant an enzyme acts upon.
Active Site: The region on the enzyme where the substrate binds.
Cofactor: Non-protein molecules that assist enzymes (e.g., metal ions).
Coenzyme: Organic cofactors (e.g., vitamins) that assist enzymatic reactions.
Apoenzyme: The protein part of an enzyme, inactive without its cofactor.
Holoenzyme: The complete, active form of an enzyme, including its cofactor.
Function: Serve as coenzymes, facilitating various biochemical reactions essential for metabolic processes.
Function: Crucial for DNA synthesis and cell division, reducing the risk of neural tube defects in the developing fetus.
Temperature: Increased temperature can enhance reaction rates up to a point but can denature enzymes beyond optimal temperatures.
pH: Each enzyme has an optimal pH; deviation can affect activity and denature enzymes.
Substrate Concentration: Higher concentrations can increase reaction rates until saturation is reached.
Competitive Inhibitors: Bind to the active site, blocking substrate access, often reversible.
Non-competitive Inhibitors: Bind elsewhere, altering enzyme activity without blocking substrate binding.
Enzymes are not consumed in reactions; they can be reused multiple times for catalysis.