1 / 11

An Overview of Bacteria: Characteristics, Nutrition, Respiration, and Reproduction

Bacteria, the oldest known life forms dating back 3.5 billion years, exhibit diverse characteristics as all prokaryotes. They can be autotrophic or heterotrophic, with sizes ranging from 0.1 μm to 500 μm. Major groups include Archaebacteria and Eubacteria, encompassing phyla like Cyanobacteria, Spirochetes, and Proteobacteria, each with unique features. Bacterial structures consist of DNA, cell membranes, and cell walls, and they reproduce rapidly via binary fission and conjugation. Bacteria play crucial roles in ecosystems but can also be pathogens producing toxins.

valentine-maldonado
Download Presentation

An Overview of Bacteria: Characteristics, Nutrition, Respiration, and Reproduction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Bacteria Dated back about 3.5 billion years ago

  2. Bacterial Characteristics • All prokaryotic • Autotrophic or Heterotrophic • Average size- 1um -500um

  3. Kingdom Archaebacteria

  4. Kingdom Eubacteria • Phylum Cyanobacteria - (blue-green algae) photosynthetic • Phylum Spirochetes - Gram negative, spiral bacteria, heterotrophic, move by a corkscrew rotation (Ex.) syphilis • Phylum Proteobacteria - Largest group, Enteric bacteria, chemoautotrophs, nitrogen-fixing bacteria. • Phylum Gram + bacteria- Have a thick layer of peptidoglycan.

  5. Bacterial Shapes • Cocci - round • Bacilli - rod • Spirilli - spiral Prefixes: • Staphylo-form clusters • Strepto - form chains

  6. Bacterial Structure • DNA (plasmid) • Cell Membrane • Cell Wall (peptidoglycan) • Glycocalyx - attachment (sticky) • Endospore - tough envelope • Capsule - protection • Pili - attachment

  7. Bacterial Nutrition • Heterotrophic - feed on dead, decaying organic matter, called saprophytes. • Photoautotrophs - use sunlight as a source of energy. • Chemoautotrophs - use chemical reactions as a source of energy.

  8. Bacterial Respiration • Obligate Anaerobes - cannot live in the presence of oxygen. • Facultative Anaerobes - can live with or without oxygen. • Obligate Aerobes - cannot live in the absence of oxygen.

  9. Bacterial Reproduction • Rapid reproduction • Heat, cold, predators, & lack of food inhibit reproduction. Methods: • Binary fission - asexual • Conjugation - sexual

  10. Production of Toxins • Pathogen - any organism that causes a disease. • Toxin - Poisonous substances that disrupt the metabolism of the infected organism. • Endotoxin - found in the cell wall • Exotoxin - secreted into areas around bacteria.

  11. Antibiotics • Inhibit growth of some bacteria. • Disadvantages: • Destroy useful bacteria as well. • Resistance of bacteria.

More Related