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Bacteria Notes

Bacteria Notes. Basic Definition. karyo. Pro. Bacteria : Prokaryotic Organisms Pro : Primitive or “prior to” Karyon : Nucleus or “kernel” Single-celled organisms without a nucleus Has circular DNA

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Bacteria Notes

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  1. Bacteria Notes

  2. Basic Definition karyo Pro • Bacteria: Prokaryotic Organisms • Pro: Primitive or “prior to” • Karyon: Nucleus or “kernel” • Single-celled organisms without a nucleus • Has circular DNA • Often has “plasmid” DNA that helps codes for genes to increase fitness (ex. Antibiotic resistance) • Bacteria can be measured in micrometers • 0.000001m or 10-6

  3. What are the two groups of bacteria? • Bacteria Cell walls with peptidoglycan • Archaebacteria • Cell walls lack peptidoglycan • Adapted to extreme environments: • Extremely hot and cold, salty, without oxygen, etc. peptidoglycan Made up of types of peptide andsugar bonds

  4. What are the basic shapes of bacteria? • Rod-shaped (Bacilli) Bacillus anthracis(Anthrax),Yersinia pestis(Bubonic plague) • Comma-shaped (Vibrios) Vibrio cholerae • Spherical (Cocci) Streptococcus, Staphylococcus • Spiral (Spirilla) Treponemapallidum(Syphillis)

  5. Bacterial Staining • Gram-positive: Retains the crystals of violet dye in the peptidoglycan of the cell wall. • Only has an inner layer of plasma membrane • Infection by this type can be treated by antibiotics such as penicillin, which attacks the peptidoglycan of the cell wall.

  6. Bacterial Staining • Gram-negative: Will not pick up much the violet dye because the cell wall is covered by an additional outer membrane, and instead appears pink. • Infection by this type must be treated by a broad-spectrum antibiotic such as ciprofloxacin that enters bacteria and disrupts protein synthesis Outer membrane Peptidoglycan Inner membrane

  7. What is a plasmid? • Plasmids are circles of DNA that can replicate separately from the main bacterial DNA. • Plasmids may carry genes that allow bacteria to survive exposure to antibiotics.

  8. Bacterial Growth and Reproduction • Binary Fission: (video) -Asexual division -DNA replicates and cytoplasm divides -Creates two genetically identical cells from one parent cell • Conjugation: (video) -Not true sexual reproduction-Sex pilusextends between bacteria -Plasmid DNA is transferred from one bacterium to another to introduce genetic diversity • Spore Formation:-Occurs when growth conditions are unfavorable -An endospore is a “spore” with a thick internal wall of membrane that encloses and protects its DNA

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