Bacteria

Eubacteria Archebacteria Protists Fungi Plants Animals

Cell type Prokaryotic Prokaryotic Eukaryotic Eukaryotic Eukaryotic Eukaryotic

Number of Cells

Unicellular Unicellular Mostly unicellular

Mostly multicellular

Multicellular Multicellular

Mode of nutrition

Autotroph or heterotroph

Autotroph or heterotroph

Autotroph or heterotroph

Heterotroph Autotroph Heterotroph

Chemistry of cell walls

Made Peptidoglycan

No peptidoglycan

Made of cellulose (in some).

Made of chitin.

Made of cellulose

No cell walls.

Six Kingdoms of Classification

What do we already know about bacteria? Small, unicellular Prokaryotic, no nucleus, not many organelles Independent, non-specialized First life on Earth

Kingdoms of Bacteria

1. Eubacteria

• Larger of the two kingdoms• Found in most environments• Cell wall contains carbohydrate “peptidoglycan”• Ex) E.coli – bacteria in your intestine helps with

digestion

Kingdoms of Bacteria

2. Archaebacteria• Cell wall lacks peptidoglycan.• Live extremely harsh

environments• Ex.) Methanogens -live in

animal digestive tracts (no oxygen gas).

Identifying Bacteria Bacteria can be identified by…

1. Shape and Arrangement2. Chemical nature of cell wall3. Gram staining4. How they obtain energy (food)

Shape and Arrangement 3 Shapes of Bacteria

1. Bacilli (rod)2. Cocci (sphere)3. Spirilla

Colony Arrangement 1. Staphlo (clump)2. Strepto (chain)

Typical Bacteria Cell

Cell wall and cell membrane

DNA Ribosomes

Chemical Nature of Cell Wall Eubacteria identified by make-up of their cell walls. Method called Gram staining is used. Gram Positive – “thick” cell wall of peptidoglycan,

purple Gram Negative – “thin” cell wall of peptidoglycan,

pink or red – can NOT be treated by many antibiotics

Obtaining Energy All living things need a method for obtaining …

-Energy (ATP)-Organic Compounds (Carbon)

1. Heterotrophs (cannot make own food) Chemoheterotrophs- take in food for both energy

and organic compounds.ex) Salmonella bacteria eat foods and release “toxins” cause food poisoning

Photoheterotrophs- Use sunlight for energy and obtain food for a source of organic compounds.

Obtaining Energy (cont.)2. Autotrophs (make own food)

Photoautotrophs – Use sunlight to make energy and organic compounds (glucose). These bacteria are all green (kind of like little plants). Many live on surface of ocean (cyanobacteria).

Chemoautotrophs- Do not use light. Instead, use chemicals in their environment to make food and organic compounds. Live where there is no light (ocean floor).

Few Other Characterisitcs of Bacteria… Obligate aerobes- Bacteria that require a

constant supply of oxygen. Ex.) Tuberculosis Obligate anaerobes- Bacteria that do not

require oxygen. Ex) Bacteria causes botulism Facultative anaerobes- Can survive with or

without oxygen. Can live anywhere. Ex) E.coli

Few Other Characteristics of Bacteria… How do bacteria

reproduce? Binary fission

-asexual = “clones”

-1st growth

-2nd DNA copied

-3rd splits - 2 cells

Conjugation Since binary fission results in clones, bacteria need a

way to gain variety. They do this through exchanging DNA in a process

called “conjugation.” Genetic material exchanged; allows bacteria obtain new

traits = antibiotic resistance Sometimes called “transformation.”