Kingdom Monera Chapter 17-2

Bacteria  Bacteria or one-celled prokaryotes are cells without a nucleus and they’re found everywhere!  Bacteria are very small; as they don’t have membrane bound organelles like eukaryotes.  All Prokaryotes are placed in two kingdoms: the Eubacteria or the Archaebacteria.

Kingdom Eubacteria  Larger kingdom  Cell wall made of complex carbohydrates (protection)  Cell membrane, which surrounds the cytoplasm. Copy Figure 17-8

 Cyanobacteria: known as the blue green bacteria.  Photosynthetic  Contain pigment phycocyanin (blue)  Contain pigment chlorophyll a (green)  The membranes that contain these pigments are different from chloroplast in plant cells.  Found everywhere, salt water, fresh water, land, hot springs, and arctic Kingdom Eubacteria-Examples

 Prochlorobacteria:  Newly discovered group  Contain chlorophyll A & B  This makes them more similar to plants. Kingdom Eubacteria-Examples

Kingdom Archaebacteria  Lack complex carbohydrate in cell wall  Live in extremely harsh environments

 Methanogens: live in oxygen free environments like thick mud and the digestive tracts of animals.  Other archaebacteria live in salty environments & hot springs. Kingdom Archaebacteria

Identification- Cell Shape  1.Rod or bacilli  2. Spherical or cocci ( coccus Greek word for berries )  3. Spiral shaped or spirilla  Bacteria can also arrange themselves in chains, clusters or pairs.  For example: streptococcus form long chains.

Streptococcus Lactobacillus, Pseudomonas Vibrio, Triponema

Grouping  Diplo- Pairs  Streptos- Chains  Staphylo- Clusters

Examples of Spherical-shaped cells Coccus (sng), cocci (pl)

A Group of two is referred to as: Diplo This is diplococccus

A Cluster of cells is referred to as: Staphylo This is Staphylococcus

A slide of typical coccus looks like this in a microscope.

Coccus

Streptococcus aurelius

Strep Throat

Staph Infection

Rod-shaped cells Bacillus (sng), Bacilli (pl)

Typical Bacillus

Bacillus

Spiral-shaped cells Spirillum (sng), Spirlli (pl)

Spirochetes

Cell Wall  We use a method called gram staining to determine what kind of cell wall a bacterium has.  Gram stains consists of two dyes: crystal violet (purple) and safranine (red).  The bacteria will take up either the purple or the red stain.

 Two kinds of cell wall:  1. One thick layer of carbohydrate and protein molecules.  Turns purple: called Gram-positive bacteria  2. Has a second layer of lipid and carbohydrate molecules.  Turns red: Called Gram-negative bacteria Cell Wall

Movement  Propel with one or more flagella  Others lash, snake or spiral forward  Others glide in their own slime like material  No movement

How Do Bacteria Obtain Energy?  Phototrophic autotrophs trap the energy from the sun like plants.  Chemotrophic autotrophs- use energy from inorganic compounds (sulfur, iron, nitrogen) to build organic compounds.  -Live in harsh environments

 Chemotrophic heterotrophs- obtain energy by taking in organic molecules and breaking them down.  Ex. Most bacteria and animals.  Salmonella competes with us for food by growing in raw meat, poultry and eggs.  Phototrophic heterotrophs- they can use the sunlight for energy, but also need organic compounds for nutrition. How Do Bacteria Obtain Energy?

 Respiration and Fermentation (with or without oxygen)  Obligate aerobes: any organism that requires a constant supply of oxygen to survive.  Obligate anaerobes: must live in the absence of oxygen.  Ex: Clostridium botulinum  Facultative Anaerobes: doesn’t require oxygen, but isn’t poisoned by its presence. How Do Bacteria Obtain Energy?

 Binary Fission: (asexual reproduction) once a bacterium has doubled in size it replicates its DNA and splits into two identical daughter cells. Types of Bacterial Reproduction

 Conjugation: (sexual reproduction) genetic information is exchanged across a protein bridge that connects two separate bacteria cells. Types of Bacterial Reproduction Note: when environmental conditions are poor, bacteria can for a thick wall called an endospore, which protects the bacteria until external conditions improve.

Beneficial Roles of Bacteria  Production of yogurt, cheese, buttermilk.  Clean up of oil spills by digesting petroleum  Symbiotic relationships with other organisms.  Ex. (humans and E. coli )  (bacteria produce enzyme that enables cows to break down cellulose)

 Recycle, decompose or break down dead material.  Break down of human sewage.  Nitrogen fixing bacteria.  Fig Beneficial Roles of Bacteria

Bacterial Diseases- Examples  Diphtheria  Tuberculosis  Typhoid fever  Tetanus  Anthrax  Botulism  Lyme Disease  Salmonella  Tooth decay

Controlling Bacteria  Antibiotics  Heat, disinfectants  Refrigeration  Sterilization by boiling, frying, steaming, canning,  Salting and pickling.