BACTERIA

Structure, Function, Reproduction, and

Growth

CLASSIFYING PROKARYOTES

There are two groups or kingdoms:

Eubacteria Live almost everywhere

Archaebacteria Live in harsh environments May be the ancestors of

eukaryotes

COMPARE THE KINGDOMS

are classified into the kingdoms of

live in harsh environments such as

include a variety of lifestyles such as

Eubacteria Archaebacteria

Infecting large organisms Thick mudLiving in soil

Animal digestive

tractsSalty lakes Hot springs

Bacteria

WHAT ARE BACTERIA?

Single-celled organisms Prokaryotes

No distinct nucleus No membrane-bound organelles

Size = 1-5 micrometers Very small, very primitive cells

About 10 times smaller than eukaryotic cells

HOWEVER, they are much larger than viruses

IDENTIFYING PROKARYOTES

Prokaryotes are identified by: Their shape The ways they move The ways they obtain energy

BACTERIA SHAPES

Bacteria come in three basic shapes

Coccus Round, spheres

Bacillus Rods

Spirillum Spiral or spring-like

MOVEMENT

Some are propelled by a flagellum

Some glide slowly along a layer of slime-like material they secrete

Some do not move at all

OBTAINING ENERGY Autotrophs

PhotoautotrophsCarry out photosynthesis (cyanobacteria)

ChemoautotrophsObtain energy from inorganic molecules (ie.

Ammonia, hydrogen sulfide, nitrites, sulfur, or iron

Heterotrophs Take in organic molecules and then break

them down Photoheterotrophs

Combination between autotrophs and heterotrophs; they photosynthesize and need organic compounds for nutrition

BACTERIA GROW IN GROUPS

Diplo Pairs

Strepto Chains

Staphlo Clusters

diplococcus diplobacillus

streptobacillus

streptococcus

staphlobacillus

staphlococcus

REPRODUCTIONBinary fission

Asexual Cell grows nearly double in size, replicates its DNA, and divides in half

Produces 2 identical “daughter” cells

View binary fission

WHAT BACTERIA NEED FOR GROWTH

Moisture Food Warm temperature Most need oxygen (aerobic bacteria),

however, some die in the presence of oxygen (anaerobic bacteria)

Where are these growth requirements met? Incubators Inside bodies of birds and mammals

WHAT STOPS BACTERIA GROWTH?

Cold temperature Dryness (freeze-dried foods) No food No oxygen (for aerobes)

BACTERIA

Beneficial and Harmful Aspects

BENEFICIAL ASPECTS Help digest food in

intestine Help in food

processing Break down waste in

sewage Ferment sugars to

make alcohol Can be used to make

medicine Decompose dead

organisms to return nutrients to soil or water

Some help fertilize soil by forming nitrates and nitrites Nitrogen-fixing

bacteria living on plant roots Convert

nitrogen into ammonia (form that plants can use)

Can be used to clean up oil spills Petroleum

eating bacteria

HARMFUL ASPECTS Spoils food

At home In stores In transit In restaurants In the field

Contaminate water Cholera & typhoid

Contaminate food Salmonella &

botulismFood needs to be

pasteurized (heated up to a really high temperature)

Damage leather Soil bacteria

Cause disease Only 1 percent of

bacteria cause disease

COMMON DISEASES CAUSED BY

BACTERIA

Tooth decayLyme diseaseTetanusTuberculosisSalmonella food poisoningPneumoniaCholera

Streptococcus mutansBorrelia burgdorferiClostridium tetaniMycobacterium tuberculosisSalmonella enteritidisStreptococcus pneumoniaeVibrio cholerae

Regular dental hygieneProtection from tick bitesCurrent tetanus vaccinationVaccinationProper food-handling practicesMaintaining good healthClean water supplies

Disease Pathogen Prevention