Bacterial Growth and Metabolism Overview

Quorum sensing

Regulatory system controlling bacterial community behaviors.

Lag phase

Initial growth stage with no cell division.

Log phase

Rapid cell division and exponential growth.

Stationary phase

Growth rate equals death rate, stable population.

Decline phase

Cell death exceeds growth, population decreases.

Biofilms

Structured communities of bacteria adhering to surfaces.

Sporulation

Process of forming spores for survival.

Catabolism

Breakdown of molecules to release energy.

Anabolism

Synthesis of complex molecules from simpler ones.

Exergonic reactions

Reactions that release energy during progress.

Endergonic reactions

Reactions requiring energy input to proceed.

Phototrophy

Energy capture through light in biochemical reactions.

Chemotrophy

Energy yield from chemical bond reactions.

Organotrophy

Metabolism using organic molecules as food.

Lithotrophy

Metabolism using inorganic molecules as food.

Aerobic organotrophy

Organic molecule metabolism with oxygen present.

Anaerobic organotrophy

Organic molecule metabolism without oxygen.

Aerobic lithotrophy

Inorganic molecule metabolism with oxygen present.

Anaerobic lithotrophy

Inorganic molecule metabolism without oxygen.

Biochemical pathways

Series of enzyme-catalyzed reactions in cells.

Entropy

Measure of disorder, relates to energy use.

Metabolism

All chemical reactions within a living organism.

ATP

Primary energy currency of cells.

Reducing power

Electrons stored in NADH, FADH2, NADPH.

Precursor metabolites

Building blocks for macromolecules.

Catabolites

Intermediates produced during catabolism.

Glycolysis

Main glucose catabolism pathway in bacteria.

TCA cycle

Tricarboxylic acid cycle for energy release.

Energy-yielding reactions

Reactions that release energy during metabolism.

Enzymes

Catalysts that speed up metabolic reactions.

Activation energy

Energy required to initiate a chemical reaction.

Exergonic reaction

Chemical reaction that releases energy.

Endergonic reaction

Chemical reaction that requires energy input.

Common energy carriers

Molecules like ATP and NADH used in metabolism.

NADH

Electron carrier used to produce ATP.

ATP formation

Requires energy input (+ΔG) for synthesis.

ATP breakdown

Releases energy when ATP is hydrolyzed (-ΔG).

Glycolysis stages

Stage 1 consumes 2 ATP; Stage 2 yields 2 ATP.

Pyruvate

End product of glycolysis, central metabolite.

Fermentation

Anaerobic process for energy production.

Respiration

Aerobic process for energy production.

Carbon skeletons

Frameworks for building macromolecules from metabolites.

Bacterial caloric intake

15% of calories from digestive tract bacteria.

Specificity of enzymes

Each enzyme catalyzes a specific reaction.

Anaerobic

Occurs without oxygen consumption during fermentation.

Lactic Acid

Common waste product of lactic acid fermentation.

Ethanol

Alcohol produced during alcoholic fermentation.

Microbial Wastes

Byproducts that inhibit further microbial growth.

Food Preservation

Using fermentation to extend food shelf life.

Diagnostic Media

Growth media containing indicators for acid production.

Phenol Red Dye

pH indicator that changes color with acidity.

Krebs Cycle

Also known as TCA cycle, breaks down pyruvate.

Acetyl CoA

Product formed from pyruvate before entering Krebs Cycle.

FADH2

Electron carrier produced in the Krebs Cycle.

Oxidative Phosphorylation

ATP formation driven by proton gradient.

Electron Transport System (ETS)

Pathway for electron transfer to oxygen.

Proton Motive Force

Energy generated by H+ ion gradient.

ATP Synthase

Enzyme synthesizing ATP using proton flow.

Glucose Respiration Equation

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O.

ATP Yield

Respiration generates more ATP than fermentation.

Mitochondria vs. Bacteria

Mitochondria produce more ATP than bacteria.

PMF

Proton motive force; energy for cellular processes.

Anaerobic Respiration

Respiration without oxygen; uses alternative electron acceptors.

Electron Acceptors

Substances that receive electrons during respiration.

Pseudomonas aeruginosa

Bacteria using nitrate in anaerobic conditions.

Autotrophy

Carbon fixation; converting CO2 into organic compounds.

Photosynthesis

Process converting light energy into chemical energy.

Oxygenic Photosynthesis

Photosynthesis that produces oxygen from water splitting.

Photolysis of Water

Splitting water to release oxygen during photosynthesis.

Carbon Fixation

Transformation of CO2 into glucose and metabolites.

Lithotrophic Carbon Fixation

CO2 fixation from mineral oxidation by lithotrophs.

Reverse TCA Cycle

Pathway for CO2 fixation in some lithotrophs.

Calvin Cycle

Pathway for CO2 fixation in phototrophs.

Biosynthesis

Building cell parts; requires energy and nutrients.

Energy Yielding Metabolism

Reactions that release energy for cellular functions.

NADPH

Electron carrier used in biosynthetic reactions.

ATP Hydrolysis

Process releasing energy for cellular activities.

Essential Elements

Nitrogen, sulfur, phosphorus needed for biosynthesis.

Facultative Anaerobes

Organisms that can switch between aerobic and anaerobic respiration.