Prokaryotes, Gram Stains, and Bacterial Metabolism

• Prokaryotes lack internal membranes and a nucleus.
• Ribosomes and DNA reside in the same location within prokaryotes.
• Most bacteria lack membranes internally.

Gram-Positive Bacteria

• Lipoteichoic acid is present.
• Peptidoglycan is on the outside.
• Easier to affect.

Gram-Negative Bacteria

• E. coli should have Lipid A.
• E. coli should not have lipoteichoic acid.
• An outer membrane protects against large antibiotics.
• Peptidoglycan is crucial.
• Peptidoglycan resides between layers.
• Harder to access.

Biofilms

• Bacteria aggregate within an extracellular matrix (slimy layer).
• Bacteria sense each other, triggering a genetic switch upon reaching a certain density.
• Motility ceases upon surface contact.

Glucose Metabolism

• Glucose is a stable molecule.
• NAD+ removes electrons from glucose, oxidizing it into pyruvate.
• NAD+ is reduced to NADH in the process.

Growth Phases

• In the death phase, viable cell count decreases while turbidity remains constant.
• Stationary phase exhibits dynamic activity.
• Some cells grow, some die, and some enter a low-energy state.
• CFU decreases.
• OD (absorbance) remains constant because bacteria do not break apart.

Endospores vs. Dipicolinic Acid

• Dipicolinic acid (DPLA) is a small molecule with significant effects.
• Proteins are large.
• Spores provide stability/strength.
• Spores can endure for tens of thousands of years.

Spore Formation

• Starvation induces spore formation.
• When starved, the treatment will allow the bacteria to grow.
• A positive control would be the starved treatment.
• A negative control would be the unstarved mutant.
• DPLA complexes with calcium to form a resistant spore coat.
• DPLA complexes with DNA, RNA, and proteins for increased stability.
• DPLA small molecule produced during spore formation.

Oxygen Requirements

• Mitochondria are consistent in eukaryotic cells.
• Bacteria use diverse terminal oxygenase compared to eukaryotic cells with mitochondria.
• Facultative anaerobes grow in the presence or absence of oxygen.
  • More ATP is produced with oxygen.
• Aerotolerant anaerobes are not killed by oxygen but cannot use it for growth.
• Obligate aerobes cannot grow without oxygen and do not ferment.

Substrate-Level Phosphorylation (Glycolysis)

• A chemical process independent of electrons or protons.
• Glucose is broken down and phosphorylated, activating electrons for removal.
• Glucose 1-6 diphosphate is generated.
• Used to generate ATP.

Fermentation

• Utilized to regenerate NAD+ for glycolysis by transferring protons and electrons from NADH.
• Pyruvate itself does not produce ATP during fermentation.
• NAD+ is essential for extracting electrons from glucose.
• Pyruvate accepts a hydrogen and electron from NADH, forming lactic acid.
• Glucose is broken down into two pyruvates.

Explores prokaryotic cell structure, focusing on the differences between Gram-positive and Gram-negative bacteria. Covers biofilms, bacterial communication, and basic glucose metabolism, highlighting oxidation, reduction, and growth phases.