Bacteria

Key Characteristics What type of cell are bacteria? Prokaryotic – they have no nucleus! How many cells is each bacterium made of? One! Bacteria are unicellular Range in size from 1 – 5 micrometers 2000 – 10000 can fit the diameter of a penny!!! Do they move? Some do and some don’t How do they reproduce? Some are sexual, while others are asexual Do they have a cell wall? Yes

Two Groups of Bacteria Eubacteria Archaebacteria Live everywhere – land, water, human body Example – E. coli – human intestines Surrounded by a cell wall made up of peptidoglycan Archaebacteria Lack peptidoglycan in cell wall DNA sequences are more like eukaryotes than eubacteria  thought to be ancestral to eukaryotes Most live in extremely harsh environments

Identifying Bacteria Shapes Groupings Cocci – spherical or round Bacilli – rod Spirrila – spiral Groupings “Diplo-” = paired “Strepto-” = chains “Staphylo-” = clusters

What shape is this? Diplobacilli

What shapes can you find in this photo?

How do they move? Some bacteria have flagella, which is a whip-like structure that acts as a tail. Some move by lash, snake, or spiral movement Some excrete a slime-like material that helps the bacterium cell glide.

Notice their tails?

Metabolic Diversity - Heterotrophs Chemoheterotrophs: Energy source – organic compounds Carbon source – organic compounds Ex = most animals and bacteria Photoheterotrophs: Energy source – sunlight

Metabolic Diversity - Autotrophs Photoautotrophs: Energy source – sunlight Carbon source – carbon dioxide Ex = all photosynthetic organisms Chemoautotrophs: Energy source – inorganic chemicals (hydrogen sulfide, iron, sulfur) Ex = chemosynthetic organisms

Where can you find chemosynthetic bacteria?

Releasing Energy – Respiration Obligate aerobes – organisms that require a constant supply of oxygen in order to live Mycobacterium tuberculosis Obligate anaerobes – organisms that must live in the absence of oxygen Clostridium botulinum – Botulism – food poisoning Facultative anaerobes – organisms that can survive with or without oxygen  perform both cellular respiration and fermentation which allows them to live anywhere E. coli

Mycobacterium tuberculosis

Clostridium botulinum Did you know that this is the same stuff they put in Botox injections?

Escherichia coli

Growth and Reproduction Binary fission – Type of asexual reproduction in which an organism replicates its DNA and divides in half, producing two identical daughter cells Conjugation – Form of sexual reproduction in which there is an exchange of genetic information Spore formation (endospores) – When growth conditions are unfavorable, bacteria form spores, which can remain dormant for months or years while waiting for more favorable growth conditions

Binary Fission

Conjugation http://www.youtube.com/watch?v=O-EdX4MaMFE

Importance of Bacteria Decomposers – Help ecosystems recycle nutrients Break down dead tissue Help in sewage treatment Nitrogen fixers – Convert nitrogen gas into a form of nitrogen that plants can use  nitrogen fixation Human uses – Production of many foods and drinks Help clean up oil spills – can digest petroleum E. coli – lives in human large intestines – produces vitamins that body cant produce on own

The Amazing World Of Gumball