Biology 240 Lecture Notes

Study Tips for Biology Exams

• Flashcards
  • Handwrite flashcards to enhance memory retention.
  • Regularly review and go through flashcards.
• Rewrite Notes
  • Rewrite lecture and reading notes to reinforce information.
• Self-Quizzing
  • Create questions from the material and test yourself.
  • Review areas where recall is weak.

Prokaryotic Classification

• Categories
  • Prokaryotic classification includes bacteria and archaea.

Bacteria

• Shapes
  • Caucasus: ball-shaped.
  • Caucobacillus: between a caucasus and bacillus.
  • Bacillus: rod-shaped.
  • Vibrio: comma-shaped.
  • Spirulium: rigid with bends.
  • Spirochetes: corkscrew movement.
  • Pleomorphic: variable shapes due to lack of cell walls.
  • Star-shaped: pointy, star-like shape.
• Arrangements
  • Single, pairs (diplococci), chains (streptococci), tetrads, sarcinae, staphylococci.

Bacterial Replication Methods

• Binary Fission
  • Common form of replication.
• Snapping
  • Daughter cells remain attached.
• Spores
  • Actinomycetes: form spores in vegetative cells.
• Budding
  • Formation of buds leading to new daughter cells.
• Viviparity
  • Daughter cells form within mother cell.

Endospores

• Formation to protect from environmental changes.
• Can form in different cell positions.
• Examples include Clostridium and Bacillus.

Classification of Bacteria

• Burgese's Manual: Lists all described bacteria.
• Taxonomy
  • Kingdom, phylum, class, order, family, genus, species.
  • Use nucleic sequence homology for classification.

Archaea

• Characteristics
  • Extremophiles, thermophiles, halophiles.
  • Lack true peptidoglycan.
  • Branched hydrocarbon chains in cell membrane.
• Methanogens
  • Produce methane in various environments.

Deeply Branching Bacteria

• Ancient bacteria relatives, e.g., Aquaflex, Deinococcus.

Phototrophic Bacteria

• Use light as energy source.
• Include cyanobacteria, green and purple bacteria.

Gram-Positive Bacteria

• Low GC Content
  • Firmicutes, Clostridia, Mycoplasma, Bacillus, Listeria, Lactobacillus, Streptococcus, Enterococcus, Staphylococcus.
• High GC Content
  • Actinobacteria: Corynebacterium, Mycobacterium, Actinomyces.

Gram-Negative Proteobacteria

• Alpha Proteobacteria
  • Nitrogen fixers, pathogenic varieties (e.g., Rickettsia, Brucella).
• Beta Proteobacteria
  • Pathogens like Neisseria and Bordetella.
• Gamma Proteobacteria
  • Purple sulfur bacteria, Legionella, Vibrio, Pseudomonas.
• Delta Proteobacteria
  • Desulfovibrio, Myxobacteria.
• Epsilon Proteobacteria
  • Campylobacter, Helicobacter.

Other Gram-Negative Bacteria

• Chlamydia
  • Obligate intracellular pathogens.
• Spirochetes
  • Trepanema (syphilis), Borrelia (Lyme disease).
• Bacteroides
  • Digestive tract inhabitants and sewage degradation.

Note: For more detailed visualization of spore formation, refer to online resources or video materials.