bio 3 Bioenergetics: Energy Transformations in Organisms

Bioenergetics

Study of energy transformations in living organisms.

Conservation of energy

Energy cannot be created or destroyed, only converted.

Entropy

Energy conversions result in energy loss as heat.

High Order Energy

Forms of energy that are more useful, like food.

Low Order Energy

Less useful energy forms, such as heat.

Normal body temperature

Typical human body temperature is 98°F or 37°C.

Skin surface area to volume ratio

Determines heat dissipation rate in organisms

Redox reactions

Electrons transfer between molecules, carrying energy.

Oxidized molecule

Loses an electron during a redox reaction.

Reduced molecule

Gains an electron during a redox reaction.

Exergonic reaction

Releases energy; products have lower free energy.

Endergonic reaction

Requires energy input; products have higher free energy.

Coupled reactions

Exergonic and endergonic reactions occur together.

Energy of activation (Ea)

Energy needed to start a chemical reaction.

Enzyme

Protein that accelerates chemical reactions.

Active site

Region on enzyme where substrates bind.

Transition state

Intermediate state during substrate transformation.

Competitive inhibition

Inhibitor blocks active site, preventing substrate binding.

Allosteric site

Secondary site on enzyme affecting active site.

Allosteric competition

Binding at allosteric site disables enzyme activity.

Allosteric activation

Binding at allosteric site enhances enzyme activity.

Induced fit model

Enzyme adjusts shape to fit substrate.

Enzyme

Proteins that catalyze biochemical reactions.

Competitive Inhibition

Inhibitor competes with substrate for active site.

Alcohol Dehydrogenase (ADH)

Enzyme converting ethyl alcohol to nontoxic substances.

Methyl Alcohol

Competitive inhibitor of ethyl alcohol on ADH.

Formaldehyde

Toxic product from methyl alcohol metabolism.

Metabolic Pathways

Series of enzymatic reactions producing cellular products.

Feedback Inhibition

Process where end product inhibits an enzyme

Substrate

Starting molecule for enzymatic reactions.

Glycolysis

First step of glucose breakdown in cytoplasm.

Pyruvate

3-carbon product of glycolysis from glucose.

Krebs Cycle

Processes acetyl CoA into CO2 and energy carriers.

Acetyl CoA

2-carbon molecule formed from pyruvate and coenzyme A.

Electron Transport Chain (ETC)

High energy electrons converted to ATP in membranes.

ATP

Main energy currency of the cell.

Anaerobic Respiration

ATP generation without oxygen in eukaryotes.

Fermentation

Process regenerating NAD+ for glycolysis without oxygen.

Hydrogen Bonds

Weak bonds affecting protein structure and enzyme activity.

pH Levels

Acidity or basicity affecting enzyme and protein function.

Salt/Ions

Chemically active particles altering protein structures.

Denaturation

Loss of enzyme structure, inhibiting its function.

NAD+

Electron carrier regenerated during fermentation.

Net Gain of ATP

Total ATP produced after glycolysis is 2.

Waste Removal

Process of eliminating byproducts from cellular metabolism.

Eukaryotic Fermentation

Two types: Lactic Acid and Alcohol.

Lactic Acid Fermentation

Occurs in muscle cells and some bacteria.

Alcohol Fermentation

Occurs in yeast, producing ethanol.

Acetic Acid Fermentation

Produced by bacteria, also known as vinegar.

ATP Gain in Fermentation

Net gain of 2 ATP per cycle.

NADH Recycling

NADH is converted back to NAD+.

Lactate

Byproduct of Lactic Acid Fermentation.

Hypoxia

Condition of low oxygen, causes lactate buildup.

Ethanol Toxicity

Ethanol buildup can kill yeast.

Champagne Bubbles

Produced by fermentation, releasing CO2.

Oxidation of Pyruvate

Converts pyruvate to acetate in mitochondria.

Acetyl CoA

Formed from acetate, enters Krebs Cycle.

Krebs Cycle

Occurs in mitochondrial matrix, generates ATP

Krebs Cycle Outputs

Produces 4 CO2, 2 ATP, 6 NADH, 2 FADH2.

Electron Transport Chain (ETC)

Uses NADH and FADH2 to create ATP.

Proton Gradient

Generated by H+ ions in ETC.

ATP Synthase

Enzyme that synthesizes ATP using proton gradient.

Final Electron Acceptor

Oxygen accepts electrons, forming water.

Chemiosmotic Coupling

Process of ATP generation via proton movement.

Triglycerides in Respiration

fats provide acetyl groups for energy.

Deamination of Proteins

Removes nitrogen, produces toxic ammonia.

Photosynthesis vs. Cellular Respiration

Both involve electron transport and gradients.

Calvin Cycle

Photosynthesis process converting CO2 to glucose.

Light Reaction

Initial phase of photosynthesis generating ATP.