University:
University of Phoenix
Course:
BIO 350 | General Biology I
Academic year:

2023
Views:

103

Pages:

4
Author:

Kasey Mitchell

Inhibitors of Oxidative Phosphorylation The inhibitors of oxidative phosphorylation are classified into: Specific Site Inhibitors that inhibit oxidation. Non-Specific Site Inhibitors that inhibit phosphorylation. 1. Specific Site Inhibitors: They block oxidation process at specific sites on the respiratory chain. Site I: These are substances that inhibit electron transport from FMN to CoQ. Site II: These are substances that inhibit electron transport from reduced Cyt b to Cyt c₁. Site III: These are substances that inhibit electron transport from reduced Cyt a to Cyt a₃. 2. Non-Specific Site Inhibitors: They function by blocking phosphorylation. These are certain compounds that can uncouple electron transport from oxidative phosphorylation. Such compounds are known as uncouplers and increase permeability of inner mitochondrial membrane to protons (H⁺). As a result, ATP synthesis doesn’t occur. Examples: 2,4-Dinitrophenol (DNP), Pentachlorophenol, etc. Concepts of pH pH is a negative logarithm of hydrogen ion concentration. pH = − log ⁡ 10 [ 𝐻 + ] pH=−log 10 [H + ] Neutral pH is 7.0. pH values lower than 7.0 are acidic, while solutions with pH values more than 7.0 are basic. Changing pH: Some chemicals can change the pH of solutions when added, increasing or decreasing its acidity. Bases remove hydrogen ions from a solution, lowering its acidity and increasing pH. Maintaining pH: Buffer solutions resist changes in pH from added acids or bases by releasing or removing hydrogen ions. Most biological buffers consist of a weak acid and a weak base. They absorb excess H⁺ ions or release them when needed to maintain pH. Buffer in Biological System A buffer is an aqueous solution consisting of a mixture of a weak acid & its salt or a weak base & its salt that resists a change in pH on the addition of either acid or base. Types of Buffers: Acidic Buffer Solution: Have pH below 7 and contain a weak acid and one of its salts. Example: A mixture of acetic acid and sodium acetate (pH ≈ 4.75). Basic Buffer Solution: Have pH above 7 and contain a weak base and one of its salts. Example: A mixture of ammonium chloride and ammonium hydroxide (pH ≈ 9.25). Physiological Buffers: Bicarbonate buffer Phosphate buffer Oxyhemoglobin buffer Importance of Buffers in Biological Research: To maintain homeostasis. To regulate enzymatic function.