Download bacteria - MHS Biology Mrs. Gates

Bacteria
singular: bacterium / plural: bacteria
1. Bacteria are classified into two kingdoms: Eubacteria (true bacteria) and
Archaebacteria (Ancient Bacteria).
2. Prokaryotic
3. Unicellular (may group together but are not multicellular)
4. Adapted to living in all environments (even some extreme) – they exist
EVERYWHERE
I. Bacterial Structure
1. Outside the plasma membrane of most cells is a rigid cell wall made of peptidoglycan
a. may also have a capsule for extra protection against host defenses.
2. No membrane bound organelles (and no membrane bound nucleus).
3. Has a single circular strand of DNA.
II. Bacteria Reproduction
Bacteria reproduce through binary fission which is the splitting of
parent cell into two daughter cells (asexual).
III. Bacteria (Energy and Nutrition)
1. Bacteria differ in their need for, and tolerance of, oxygen (O2).
a. Aerobic bacteria require a constant supply of O2 to carry out
cellular respiration.
b. Anaerobic bacteria do not require oxygen.
- Obligate anaerobes are unable to grow in the presence of O2; this includes
anaerobic bacteria that cause
botulism, gas gangrene, and tetanus.
- Facultative anaerobes are able to grow in either the presence or absence of
oxygen.
a
2. Autotrophic Bacteria
a. Photoautotrophs are photosynthetic and use light energy to assemble the
organic molecules they require. (cyanobacteria)
b. Chemoautotrophs obtain energy by removing electrons from inorganic molecules
such as ammonia, hydrogen sulfide or from organic molecules such as methane and
nitrogen. (methanogens, nitrogen fixation/nitrification)
3. Heterotrophic Bacteria
a. Most free-living bacteria are heterotrophs.
b. Along with fungi, they are the principal decomposers of the living world. (break
down the bodies of dead organisms and make the nutrients available to other
organisms.
c. Detritivores (saprophytic bacteria) are critical in recycling materials in the
ecosystem; they decompose dead organic matter and make it available to
photosynthesizers.
IV. Bacterial Diseases in Humans
a. Bacteria that cause disease are called pathogens.
b. Anthrax, Bubonic plague, dental cavities, Lyme disease, Tuberculosis.
V. BACTERIA CLASSIFICATION
1. The Gram stain procedure (developed in the late 1880s by Hans Christian
Gram) differentiates bacteria.
a. Gram-positive bacteria stain purple (thick cell wall)
b. Gram-negative bacteria stain pink (thin cell wall).
2. Bacteria have three basic shapes.
a. A spirillum is spiral-shaped.
b. A bacillus is an elongated or rod-shaped bacteria.
c. Coccus bacteria are spherical (round).
VI. Bacteria and Health
Antibiotics
The Discovery of Penicillin by Alexander Fleming
 Noticed mold (fungus) growing on petri dishes. Bacteria did not grow where the
mold was.
 He isolated the chemical that killed bacteria, but it was not stable
 Howard Flory continued the work, later stabilized the chemical
 Fleming and Flory received the Nobel Prize in 1945
Antibiotic-Resistant Bacteria
-Mutations for antibiotic resistance arise spontaneously
- Bacteria multiply very rapidly (doubling their numbers in as few as 20 minutes) so
an antiobiotic-resistant bacteria can spread quickly throughout a population)
Good Bacteria
-Many foods we eat are processed by specific bacteria. (pickles, buttermilk,
cheese, yogurt)
-Industrial use (chemicals)
-Genetic engineering companies use to produce medicine and complex chemicals
for research.
Fungi
singular-fungus/plural-fungi
1. Eukaryotic
2. Unicellular (yeasts)/multicellular
3. Absorbitive heterotrophs. (Hyphae grow into the food source, release a
chemical that digests the food and then absorb it. All fungi obtain nutrients by
secreting digestive enzymes that break down organic matter in their
environment. They then absorb the decomposed molecules.
I. Structure
1. All fungi except yeasts have filamentous bodies (composed of slender filaments)
called hyphae.
2. When hyphae grow, they branch and form a tangled mass called a mycelium.
3. Hyphae and mycelium make a fungus well suited for absorbing nutrients from its
environment.
4. Cell walls made of chitin.
II. Fungal Reproduction and Classification
1. Reproduce via spores. (usually transported by the wind)
2. Sexually & Asexually
3. Fungi are classified by structures produced during sexual reproduction.
a. Phylum Zygomycota (black bread molds)
b. Phylum Ascomycota (morels, truffles, yeasts)
c. Phylum Basidiomycota (mushrooms, puffballs, rusts, smuts
III. Fungi and Health
1.Parasitic fungi compete for nutrients with their hosts. (athlete’s foot and
yeast infections)
2.Antibiotics, such as penicillin, are produced by fungi.
Some fungi are commercially valuable.
-Yeasts are useful in baking, brewing, and wine-making.
-Other fungi provide the flavor and aroma of cheeses.
IV. Symbiotic Relationships
1. Mycorrhizae- mutualistic relationship formed between fungi and plant roots.
a. Hyphae help transfer phosphorous and other minerals from soil to roots.
b. Plant supplies carbohydrates to the fungus.
2. Lichens- symbiosis between a fungus and a photosynthetic partner (green
algae, cyanobacterium or both)
a. Photosynthetic partner provides carbohydrates
b. Fungal partner protects it from the environment.
Protists
1.
2.
3.
4.
First Eukaryotes
Mostly unicellular and some multicellular (algae)
Autotrophs and heterotrophs
Most diverse of all organisms, contains all eukaryotes that cannot be
classified as animals, plants or fungi.
5. Most live in water (though some live in moist soil or even the human body)
I. Animal-like Protists: Protozoans
1. All animal-like protists are heterotrophs.
2. All animal-like protists are able to move in their environment in order to find
their food.
3. Animal-like protists are all unicellular. (unlike animals which are multicellular)
Four Phyla of Animal-like Protists - Classified by how they move




Zooflagellates – flagella
Sarcodines – extensions of cytoplasm (pseudopodia) (amoeba)
Ciliates – cilia (paramecium)
Sporozoans – do not move (malaria)
II.
Plant-like Protists
1. Plant-like protists are autotrophic.
2. They can live in soil, on the bark of trees, in fresh water, and in salt water.
3. These protists are very important to the Earth because they produce a lot of
oxygen.
4. Form the base of aquatic food chains.
5. Can be unicellular, multicellular, or live in colonies.
6. Divided into four basic groups:
a. euglenoids –unicellular, autotrophs-day, heterotrophs-night
b. dinoflagellates-unicellular, plankton
c. diatoms -unicellular
d. algae (green-unicellular , red & brown-multicellular)
III. Fungus-like Protists
1.
2.
3.
4.
Fungus-like protists are heterotrophs with cell walls.
They also reproduce by forming spores.
All fungus-like protists are able to move at some point in their lives.
There are essentially three types:
a. water molds and downy mildews
i. Attack food such as potatoes, cabbage, and corn
ii. Live in water or moist environments
b. slime moldsi. feed on bacteria and other microorganisms
ii. Live in moist soil and on decaying plants and trees
iii. Very colorful
IV. Protists and Health
-Diseases caused by Protists- Malaria, African sleeping sickness, Amebic
dysentery
-Beneficial Protists
-commensal protists (aid in digestion)
-plankton-help support food chains
-Single largest group of photosynthesizers
-recycle important chemicals (nitrogen, carbon, phosphorus)