Biology Ch. 16 Prokaryotes
16.1 Pathogens Disease causing agents = virulent
16.2 Bacteria A domain of prokaryotes that have the following traits
Have some unique rRNA sequences
Have peptidogycan in cell wall
Don’t have histones in DNA
Archea A domain of prokaryotes more similar to eukaryote with the following traits
Have similar rRNA sequences as eukaryotic cells
Don’t have peptidoglycan in cell walls
Have histones in DNA in some species
Peptidoglycan A material found in bacterial cell walls. It’s a polymer of sugars cross linked by short polypeptides. Archea don’t true peptidoglycan.
16.3 Cocci Spherical cells that occur in chains or clusters
Bacilli Rod shaped prokaryotes. Most occur single but some occur in pairs.
Curved or spiral Vibrios – shaped like a comma
Spirillium – helical, short
Spirochetes – helical long
16.4 Gram stain A technique used to identify whether a cell is gram- positive or negative.
Gram-positive
bacteria Have simple cell walls with a thick layer of peptidoglycan.
Gram-negative
bacteria Have complex cell walls with less peptidoglycan and an outer membrane of lipids bonded to
carbohydrates. These are more dangerous because they have a capsule around them which protects them from antibiotics and helps attach to surfaces.
Pili An appendage that adhere to each other or to surrounding surfaces.
Motile Prokaryotes that possess whiplike flagella Flagella Long things to help prokaryotes move
Endospores Have a thick protective coat which can dehydrate and is tolerant of extreme conditions. When conditions improve the endospore takes in water and resumes growth
16.5 Autotrophs Prokaryotes that obtain carbon from carbon dioxide Heterotrophs Organisms that obtain their carbon atoms from other
organisms
Photoautotrophs Prokaryotes that are photosynthetic and use the
power of sunlight to convert carbon dioxide into organic compounds
Chemoautotrophs Use carbon dioxide as their source of carbon but get energy from oxidizing inorganic substances such as hydrogen sulfide or ammonia
Photoheterotrophs Use light to make ATP but must obtain their carbon from an outside source already in fixed organic compounds.
Chemoheterotrophs Get both carbon and energy from organic compounds.
16.6 Extreme halophiles (salt lovers) thrive invery salty places.
Extreme
thermophiles Thrive in very hot water. Live near deep sea ocean vents.
Methanogens Live in anaerobic environments and give off methane as a waste product. Live at bottoms of lakes and swamps
16.7 Nine Groups of bacteria
Proteobacteria A clade of gram-negative bacteria which contains 5 groups of bacteria
Chlamydias Live inside eukaryotic host cells
Spirochetes A group of helical bacteria that spiral through their environment by means of rotation.
Gram-positive
bacteria Opposite of proteobacteria.
Cyanobacteria The only prokaryotes with plant like, oxygen generating photosynthesis.
16.8 Exotoxins Proteins secreted by bacterial cells and include some of the most powerful poisons EX. lockjaw, and tecnis Endotoxins Components of the outer membrane of gram-negative
bacteria that are released when the cell dies or is digested by a defensive cell.
-Endotoxins produce septic shock (a drop in blood pressure), fever, aches. One genus causes bacterial meningitis and other food poisoning.
-The most widespread pest-carried disease in the united states is Lyme disease caused by borrelia bondorferi carried in ticks that live in deer and field mice.
16.10 Bioremediation The use of organisms to remove pollutants from soil air or water. Prokaryotic decomposers are the mainstays of our sewage treatment.
Protists
Most are unicellular but some are multicellular
All are eukaryotic
Some autotropic
Some are heterotropic
Parasitic – eat alive organisms
Saprophyte – living off something dead.
3 Categories of Protists 1. Fungus like
a. Slime molds b. Decomposers 2. Plant like (algae)
a. Brown algae 3. Animal like (protozoans)
a. Ciliates ECT.
b. Locomotion –cilia, flagella, c. Plasmodium (causes malaria
4. Symbiosis – close association between organisms of two or more species 5. Endosymbiosis – how eukaryotic cells accumulated mitochondria and
chloroplasts, the dna for these organelles became incorporated into the cells chromosome
6. Secondary endosymbiosis – contributes to the diversity of protists. It is when an already endosymbiotic protists goes though endosymbiosis to create an organisms that is secondary endosymbiotic.
Protists Classification 1. Unknown Clade
a. Diplomonad
i. Ex. Giardia intestinalis a parasite in water.
ii. All diplomonads are parasites.
b. Parabasalids
i. Ex. Trichomonas vaginalis ii. All are parasites
iii. Generate energy anaerobically c. Euglenozoans
i. Ex. Tripanosoma sp. Which causes African sleeping sickness carried by tse tse fly
ii. Some are parasites but not all, all have flagellum
iii. Presence of a crystalline rod of unkown function in flagella iv. Ex. Euglena - have a red eyespot
2. Alveolates – have membrane enclosed sacs or alveoli beneath the plasma membrane. Hypothesized to stabilize the cell surface or regulate water and ion content.
a. Dinoflagellates
i. Many are bioluminescent algae
ii. Cause red tides or dinoflagellate blooms
iii. These and diatoms are known as plant floaters and make up phytoplankton.
b. Ciliates
i. Ex. Paramecium, Stentor, and Vorticella.
ii. Characterized by one macronucleus for everyday function and many micronuclei for sexual reproduction.
iii. Paramecium can attach with sex pili and exchange micronuclei.
iv. These are protozoans v. Move using cilia c. Apicomplexans
i. Ex. Plasmodium carried by misquitos and causes malaria.
ii. All are parasites
3. Stramenopiles – named for their hairy flagellum usually paired with a smooth flagellum
a. Water molds
i. Cause of Irish potato famine ii. Have many flagellas
iii. Fungus like
iv. Usually decomposers b. Diatoms
i. Algae
ii. Have a two part glass wall made of silica.
iii. Are the source of oil c. Brown Algae (kelp)
i. Brown color is a pigment
ii. These are large complex stramenopiles 4. Amoebozoans – use pseudopodia to move and feed
a. Amoebas – move by pseudopodia b. Slime molds
i. Ex. Physarium ii. Fungi like
iii. Feeding stage is called the plasmodium iv. Are one large cell with many nuclei
v. Reproductive stage of plasmodial slime mold is called the fruiting body which releases spores
vi. Coenocytic – a one celled organism consisting of many nuclei.
vii. Plasmodial Slime mold – a single cell of a slime mold 5. Others
a. Red Algae
i. An accessory pigment makes them red ii. Important component of coral reefs
iii. Used in making auger (a thickening agent) b. Green algae
i. Clamydomonas (has eyespot and two flagella or is biflagellated), ii. Ulva (sea lettuce), goes through alternation of generations.
iii. Volvox (forms colonies in the form of hollow balls) iv. Closest relative of land plants
c. Forams and Radiolarians
i. Have threadlike pseudopodia to move and feed, which extend through the test.
ii. Forams’ shell is called a test and forams shell is made of calcium carbonate
iii. Radiolarians have internal skeleton made of silica which is very porous.