Enzyme Activity Influencers:
Factors Affecting Activity:
Solute concentration: Higher concentration increases activity.
Temperature: Enzymes have optimal temperatures. For instance, an enzyme shows peak activity at 24°C.
Activators: Molecules that increase enzyme activity.
Inhibitors: Substances that decrease activity, classified into:
Competitive inhibitors: Bind at the active site.
Non-competitive inhibitors: Bind elsewhere, altering enzyme shape.
Covalent vs. Non-Covalent Bonds:
Covalent bonds: Irreversible; form when substrates bind very tightly (e.g., certain inhibitors).
Non-covalent bonds: Reversible; essential for enzyme-substrate interactions.
Overview:
Universal first step in energy production, occurs in all cells (prokaryotes and eukaryotes).
Takes place in the cytoplasm.
Steps of Glycolysis:
Ten Enzyme Process:
First five steps (endergonic) consume 2 ATP to prepare substrates.
Last five steps produce 4 ATP (net gain of 2 ATP).
ATP production through substrate-level phosphorylation.
Importance:
Produces pyruvates, essential for subsequent cellular respiration pathways.
Types:
Aerobic respiration: Requires oxygen.
Anaerobic respiration: No oxygen required (e.g., fermentation).
Glycolysis Role :
Central process leading to either aerobic or anaerobic respiration.
Pyruvate Oxidation:
Connects glycolysis to the citric acid cycle; does not produce ATP but prepares carriers (NADH, FADH2).
Citric Acid Cycle:
Produces additional 2 ATP via substrate-level phosphorylation.
Final Step of Cellular Respiration:
Takes place in the inner mitochondrial membrane; involved in transforming NADH and FADH2 into ATP.
Mechanism:
Electrons transferred through proteins in the electron transport chain, pumping H+ ions into the intermembrane space.
Creates a gradient utilized by ATP synthase to produce 28 ATP through oxidative phosphorylation.
Oxygen's Role:
Final electron acceptor; forms water as a byproduct.
Recycling:
FADH2 and NADH are recycled back to earlier steps to sustain the process.
Glycolysis is essential for initiating cellular respiration, regardless of aerobic or anaerobic pathways.
Net products of glycolysis: 2 ATP, 2 NADH, and 2 pyruvate.
Key enzymes: Understand the role of ATP synthase and the function of specific phases (endergonic vs. exergonic).
Overall ATP Yield: Up to 30-32 ATP from complete cellular respiration, contingent on substrate availability and metabolic pathways.