Lecture_Study_Guide__Microbial_Metabolism

Page 1: Lecture Study Guide: Microbial Metabolism

Definition of Metabolism

  • 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 vs. Anabolism

  • 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.

Energy Storage

  • 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.

Enzymes

  • Composition: Enzymes are typically proteins composed of amino acids.

  • Importance: They catalyze chemical reactions, increasing the reaction rates necessary for life processes.

Naming of Enzymes

  • Enzyme Name Indicators: Often end in "-ase" (e.g., lactase, protease), indicating their function.

Enzyme Functionality

  • Activation Energy: The minimum energy required to initiate a chemical reaction; enzymes lower this energy barrier.

Key Terms in Enzymatic Activity

  • 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.

Importance of Vitamins

  • Function: Serve as coenzymes, facilitating various biochemical reactions essential for metabolic processes.

Importance of Folic Acid for Pregnant Women

  • Function: Crucial for DNA synthesis and cell division, reducing the risk of neural tube defects in the developing fetus.

Factors Affecting Enzymatic Activity

  • 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.

Enzyme Inhibition

  • Competitive Inhibitors: Bind to the active site, blocking substrate access, often reversible.

  • Non-competitive Inhibitors: Bind elsewhere, altering enzyme activity without blocking substrate binding.

Behavior of Enzymes After Reactions

  • Enzymes are not consumed in reactions; they can be reused multiple times for catalysis.

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