PROKARYOTE S María Paula Vélez R

Prokaryotes are the most numerous organisms on earth. They are found almost everywhere, from the skin of a fingertip to the waters of a thermal geyser to the freezing landscape of the Artic.The earliest fossils of prokaryotes indicate that they lived before other forms of life evolved. María Paula Vélez R

Prokaryotes are single-celled organisms that do not have a membrane-bound nucleus. María Paula Vélez R

Archaebacteria Archae are not like bacterias in many ways. For example, their cell walls do not have peptidoglycan (protein found in bacterias cell wall). Archae were first discovered in extreme environments such as swamps, salt lakes and hot springs. María Paula Vélez R

Archeal groups: 1.Methanogens: Convert hydrogen gas and carbon dioxide into methane gas. Oxygen is poisonous for them, so they can live only in places that lack oxygen. Example: methanogens that live in the intestinal tract of the cow. María Paula Vélez R

2. Halophiles: “salt-loving” archae that live in environments that have very high salt concentration such as the Dead sea. María Paula Vélez R

3. Thermoacidodophiles: live in very acid environments that have also very high temperatures. Some can live up to 110°C and at a ph less than 2 (strong acid). They can live near volcanic vents or hydrothermal vents. María Paula Vélez R

Eubacteria Most known prokaryotes are eubacteria. They occur in many shapes and sizes and have different genetic characteristics. There are three main ways to classify them: -By cell wall -By shape -By biochemical properties and evolutionary relations. María Paula Vélez R

Cell wall: Gram-positive Simpler and have more Peptidoglycan. Gram negative complex cell wall and small amount of peptidoglycan. María Paula Vélez R

Shape:

Biochemical properties and evolutionary relations: -Proteobacteria (most are symbiotic) -Gram positive (most cause diseases) -Cyanobacteria (photosynthetic bacterias) -Spirochetes (gram-negative) -Chlamydia (gram-negative cocci) María Paula Vélez R

HELPFUL BACTERIA

HARMFUL BACTERIA María Paula Vélez R

Homework Investigate: 1. Two diseases caused by bacterias. 2. What are antbiotics. María Paula Vélez R