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.