Kingdom Monera Chapter 17-2. Bacteria Bacteria or one-celled prokaryotes are cells without a nucleus and they’re found everywhere! Bacteria are very.

Kingdom MoneraChapter 17-2

BacteriaBacteria 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 EubacteriaLarger 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.PhotosyntheticContain 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 & BThis makes them more similar to plants.

Kingdom Eubacteria-Examples

Kingdom Archaebacteria

Lack complex carbohydrate in cell wallLive 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 bacilli2. Spherical or cocci (coccus Greek word

for berries)

3. Spiral shaped or spirillaBacteria can also arrange themselves

in chains, clusters or pairs.For example: streptococcus form long

chains.

Streptococcus

Lactobacillus, Pseudomonas

Vibrio, Triponema

GroupingDiplo- PairsStreptos- ChainsStaphylo- Clusters

Examples of Spherical-shaped cells

Coccus (sng) , cocci (pl)

A Group of two is referred to as: DiploThis is diplococccus

A Cluster of cells is referred to as: StaphyloThis 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

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 botulinumFacultative 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 17-18

Beneficial Roles of Bacteria

Bacterial Diseases- Examples

Diphtheria Tuberculosis Typhoid fever TetanusAnthrax

BotulismLyme DiseaseSalmonellaTooth decay

Controlling Bacteria

AntibioticsHeat, disinfectantsRefrigerationSterilization by boiling, frying, steaming,

canning, Salting and pickling.