Diversity of Living Things Bacteria

Classification of Bacteria Bacteria and prokaryotes are classified based on: 1) Their shape and colony groupings.

Classification of Bacteria Bacteria and prokaryotes are classified based on: 2) The structure of their cell wall. Bacterial Peptidoglycan Cell Wall Cell Membrane

Classification of Bacteria Bacteria and prokaryotes are classified based on: 3) Their sources of food or metabolism.

Bacterial Shapes All bacteria are unicellular, however, some cells stick together in colonies. - Cocci – sphere shaped bacteria - Bacillus – rod shaped bacteria - Spirrillium – spiral shaped bacteria

Colony Shapes All bacteria are unicellular, however, some cells stick together in colonies. - Diplo - cells arranged in pairs - Staphylo - cells arranged in clusters resembling grapes - Strepto - cells arranged in a chain

Cell Wall Structure - A thin layer of cell wall protein makes Gram negative bacteria stain pink. - A thick later of cell wall protein makes Gram positive bacteria stain purple.

Gram +ve Gram -ve Cell Wall Structure

Food and Metabolism - The four groups are: 1) Photoautotrophs - use light energy for photosynthesis and get carbon from CO2. CO2

Food and Metabolism - The four groups are: 2) Photoheterotrophs - consume other organisms to get carbon and use light energy

Food and Metabolism - The four groups are: 3) Chemoautotrophs - get energy by breaking bonds in inorganic molecules like ammonia (NH3) and hydrogen sulphide (H2S).

Food and Metabolism - The four groups are: 4) Chemoheterotrophs - get both their carbon and energy from eating organic molecules like sugar that are made of carbon (C) and hydrogen (H).

Movement Flagellum - A whip-like tail for motion. Cilia - Tiny hairs on the surface of the cell beat and move cell.

Reproduction - Binary Fission Bacteria usually reproduce asexually by using binary fission. The bacterial cell copies the genetic infomratyion in the loop of DNA, then splits into two identical daughter cells.

Reproduction - Binary Fission

Reproduction - Conjugation - Bacteria can share DNA sexually using conjugation. - A bacterial plasmid DNA loop containing genetic information can be transferred from one bacterial cell to another. - DNA from the plasmid loop can integrate into the chromosome DNA loop.

Reproduction - Conjugation Step 1 Step 2 Step 3

Spore Formation - Endospores - A spore is a type of dormant cell. - Exhibits no signs of life. - Highly resistant to environmental stresses such as: - High temperatures - Irradiation - Strong acids - Disinfectants

Spore Formation - Endospores

Beneficial Bacteria Not all bacteria are harmful to humans, their usefulness far outweights the damage they do.

Beneficial Bacteria Bacteria help in: - Decomposing dead things.

Beneficial Bacteria Bacteria help in: - Helping organisms (including us) digest food.

Beneficial Bacteria Bacteria help in: - Helping clean up toxins that seep into soil and water.