microbiology
study of microbes: bacteria, archea, protists, fungi, prions, and viruses
primary producers
photosynthetic protists and bacteria are _____ ______
LUCA
last universal common ancestor --> what all life is traced back too
1
stage ___ of microbial life origin
-organic monomers
-evolution of monomers, primordial soup
2
stage ___ of microbial life origin
-organic polymers
-evolution of polymers
3
stage ___ of microbial life origin
- protobionts
-evolution of protobionts
-development of cell membrane
4
stage ___ of microbial life origin
- living cells
-evolution of living cells
archaea
-no nucleus or organelles
- sometimes introns
-has histones
-several types of RNA polymerase
-methione is at start of protein synthesis
eukarya
-has nucleus and organelles
-has introns and histones
-several types of RNA polymerase
-methione is at start of protein synthesis
archaea
-small
-genome is a single, closed, circular DNA molecules
-plasma membrane single lipid layer w/ branched side chains
halophiles, thermacidophiles, methanogens
three types or archaea
halophiles
- type of archaea
-12 - 15%
-lives in salty habitats
Thermacidophiles
-type of archaea
-extremely hot, acidic, aquatic enviroments
-evolved to function at temps as high as 80�C
methanogens
-type of archaea
-use CO? and H? as energy sources
-produce methane as byproduct
-in anaerobic environments --> swamps and animal intestinals
bacteria
-most common prokaryote on earth
-0.2-.1�m in size
-has 3 shapes
-has single circular chromosome located in nucleoid region
rod, spherical, spiral/helical
three bacteria shapes
flagella
used for motion in bacteria
plasmids
accessory rings of DNA that carry certain genes, such as antibiotic resistance that many bacteria have
binary fission
-how bacteria reproduce asexually
-bacterial cell replicates its genome and divides into 2 new daughter cells
conjugation, transformation, transduction
three mechanisms of genetic recombination
conjugation
genetic recombination where donor cells passes DNA to a recipient cell by way of sex pilus
transformation
genetic recombination where bacterium takes up DNA from environment released by dead bacteria
transduction
genetic recombination where viruses carry bacterial DNA from cell to cell
heterotrophic
- most bacteria are this
-require organic carbon for food
chemoautotrophs
- some bacteria are this
-use inorganic chemicals to fix CO? into organic form
photoautotrophs
-cyanobacteria are this
-have chlorophyll and do photosynthesis that releases O?
false
T/F
Do most bacteria cause diseases?
streptococcus pyrogenes
bacteria that causes the most diseases
Staphylococcus aureus
-bacteria that causes some diseases in upper respiratory tract
-abt 20% of people are carriers
-usually limited to skin infections
-has strain called MRSA that is resistant to methicillin
-abt 50,000 deaths a year
Clostridium botulinum
-type of food poisoning
-bacteria that produces one of the most toxic substances on earth
-grows in FOOD
-lots of vomiting and diarhhea
salmonella
-type of food poisoning
-symptoms occur several days after consumption
-causes infection while growing in INTESTINES
antibiotic
inhibit bacteria by interfering w/ a unique metabolic pathway of bacteria
-inhibit protein synthesis by bacteria
-inhibit cell wall biosynthesis
viruses
-acellular structures that are parasites
-use host cell's replication machinery (ribosomes and certain enzymes)
-smaller than bacteria
-made up of a capsid and nucleic acid core
capsid
-outer portion of virus
-surrounded by lipid envelope
-may have spikes for attachment
nucleic acid core
-inner component of virus
- DNA or RNA
influenza virus
-causes flu
-more severe symptoms that can cause death
-changes rapidly
rhinovirus
-causes common cold
-not very severe symptoms
reproductive cycle of virus
1. attachment: spike combines with receptor
2. entry: virus enters cell and uncoating occurs
3. replication: many copies of viral RNA genome are made
4.biosynthesis: viral components are synthesized
5. assembly: new viruses are now present
6. budding: vir
prions
-protein infectious particles
-normal proteins change their shape and causes other normal proteins to change their shape
-causes degenerative diseases in nervous system
-these are passed down through ingestion of infected tissues
organic monomer stage
-stage 1 of microbial life orgin
-all 22 amino acids are formed
-conditions were similar to early earth atmosphere
protists
-Eukaryotes that are not plants, animals, or fungi
-very diverse
-many unicellular, colonial, and multicellular form
-protists have sex and meiosis
-all have mitochondria
edosymbiotic theory
explains the origin of mitochondria and chloroplasts
1. cell gains nucleus
2. cell gains endomembrane system
3. cell gains mitochondria
4. cell gains chlorplasts
Photoautotrophs
-algae
-protist that produces food by photosynthesis
heterotrophs
two types in protists
-protozoans: eat bacteria and other protists
-parasites: derive nutrition from a living host, which is harmed by this interaction
mixotrophs
protists that use both photosynthesis and heterotrophy
node
a branch point on phylogenic tree
polytomy
when more than two branches come from a single node of a phylogenic tree
archaeplastids
-derived from endosymbiotic cyanobacteria
-land plants
-green algae (chlorophytes and charophytes)
-red algae
-sexual reproduction by conjugation
chromoalveolates
-very large, diverse group of protistans
spirogyra
-example of of a charophyte
-filamentous green algae with ribbon-like chloroplast
diatoms
-a chromalveolata
-unicellular algae
-20-25% of photosynthesis
-glossy cell wall containing silica
-freshwater and marine
-formed from fossililzed remains
kelp
-a chromalveolata
-attached to seafloor
-can be 60 m in length
-primary producers for diverse and productive community
dinoflagellates
-a chromalveolata
-unicellular algae
-cause blooms in polluted coastal waters ( red tides, bioluminescent ocean)
cilliates
-a chromalveolata
-unicellular protists including heterotrophs
-use cilia to move and to sweep food into thier mouth
flagellates
-an excavate
-most are heterotrophic protozoans that propel themselves using one or more flagella
-has feeding groove
euglena
-an excavate
-photosynthesis
-mixotrophy
-eyespot for detecting light intensity
-flagella
amoeba
-organism with pseudopodia
-free-living
-fed by phagocytosis
-closest related to animal/fungus group
plasmodial slime mold life cycle
-diploid multinucleate
-plasmodium develops many sporangia during unfavorable conditions
-the spores survive until moist and able to germinate
-spores release haploid amoebae
-haploid amoebae ear decomposers and reproduce ir act as gametes and fuse
hyphae
body mass of individual filaments in fungi
mycelium
mass of hyphae in fungi
large surface area
what is the main purpose of hyphae to mycelium?
ascomycetes
-sac fungi
-have ascocarp: cup-like sexual reproductive structure
-many reproduce using conidia: asexual spores
-many are yeasts
basidomycetes
-club fungi
-have basidium: secual reproductive structure within the basidiocarp (edible part of mushroom)
lichens
-associations between fungi and cyanobacteria or green algae
-efficient at occuring nutrients and moisture
-can colonize poor soil, rocky surfaces
-are primary colonizers
Mycorrhizae
-mutualistic relationships with plant roots
-allows plants to grow better in poor soils
-plant provides products of photosythesis to fungus
-fungus provides minerals and water to plant roots
-almost all plants form these relationships
5 evolutionary events to live on land
development of ...
-embryo protection
-vascular tissue
-megaphylls (large leaves with branching veins)
-seeds
-flowers of fruits
fern life cycle
1. Sporophyte
2. Sporangia
3. Spores
4. Gametophyte
5. Fertilization
6. Zygote
7. Fronds
nonvascular plants
-no seeds
-small
-live in very moist areas
-gametophyte is dominant
-has u
sporophyte
-2n or diploid
-produces spores by meiosis
gametophyte
-n or haploid
-produces gametes by mitosis
-sperm and egg fuse to form diploid zygote
ferns
-seedless vascular plants
-have true roots, stems, and leaves
-sporophyte dominant
-fronds are compound and grow from horizontal stem
-spores are on bottom of frond, which are megaphylls
club mosses
-lycophytes
-seedless vascular plants
-upright stems
gymnosperms
-plant in which seeds are not enclosed by plants/flowers and usually in cones
-conifers and gingkoes
-adapt well to cold,dry weather
angiosperms
-plants that have seeds within flowers
-seeds develop from ovule within an ovary
-flowers are for pollination
radial symmetry
body plan in which body parts repeat around the center of the body
bilateral symmetry
line down midline produces nearly identical images
invertebrates
-lack an edoskeleton
-no backbones
- evolved first
vertebrates
-have endoskeleton of bone and cartilage
porifera
the phylum of sponges
sponge
-cellular level
-sac-like body with spores
-multicellular but have no organized tissues
-filter feeders
-choanocytes
-spongin: proteinaceous skeleton
cnidarians
-have radial symmetry
-all aquatic
-have stinging cells that are used to capture prey or stay safe
corals
-a cnidarian
-polyp similar to anemones, but encased in calcium carbonate house
-solitary or form elaborate colonies
sea anemone
-a cnidarian
-sessile polyps attached to substrate under water
jellyfish
-a cnidarian
-primary stage is a medusa with bell-shaped mouth and is directed downward
protosomes
multicellular organism where blastopore becomes mouth
trochozoans
include flatworms, molluscs, annelids
platyhelminthes
Phylum of flatworms
planarians
-free-living flatworms
-have muscular, excretory, reproductive, and digestive systems
-feeds in small organisms
tapeworm
A parasitic flatworm characterized by the absence of a digestive tract, and a long body of repeated units
molluscs
-has visceral mass, foot, and mantle
- also has radula
gastropods
-a mollusc
-includes conches and snails
-foot is flattened ventrally
-move by muscle contractions along the foot
cephalods
-a mollusc
-includes squid, octopus, and nautilus
-foot evolved into funnel or siphon
-powerful beak and radula used for feeding
-cephalization is apparent
bivalves
-a mollusc
-includes clams, oysters, scallops, and mussels
-2 part shells made of portein and calcium carbonate
-gills located within the mantle cavity used for gas exchange
-filter-feeders: water enters thru incurrent siphon
annelids
-segmented worms
-no internal or external skeleton
-each segment moves independently
-moves by contraction and expansion of each segment
earthworms
-an annelid
-class oligocaetes
-scavenges on dead or living organisms
-have few setae per segment
-head is not well formed
-gas exchange is across body wall
-evidence of segmentation in many systems
-hermaphroditic
ecdysozoans
-arthropods and roundworms
-constructs an outer covering called a cuticle
-has protection for animal
-sheds to allow growth
arthropods
-an ecdysozoan
-has segmentation and joint appendages
-has endoskeleton
-has variety of respiratory organs
-most undergo metamorphosis
crustaceans
-an ecdysozoan
-marine arthropod
-freshwater and terrestrial
-has hard exoskeleton
insects
-an ecdysozoan
-divided into head, abdomen, and thorax
-most have wings and antenae
arachnids
-an ecdysozoan
-scorpions, spiders, ticks, and miles
-has 6 pairs of appendages
-has abdomen and cephalothorax
deuterostomes
-blastopore becomes anus
-invertebrate
echinoderms
-diverse group of marine animals
-endoskeleton made of calcium-rich plates
-has spines sticking out of the skin
-has radial symmetry as adults and bilateral as larva
sea urchins
-an echinoderm
-small, round sea animals with spiny shells
sea stars
-an echinoderm
-found along shoreline on rocky surfaces
-5 rayed body w/ mouth on underside and anus on upperside
lancelets
-nonvertebrate chordate
-live in shallow coastal waters
-has all 4 chordate characteristics
-filter feeder
chordate
organisms with
-notochord: dorsal supporting rod
-dorsal tubular nerve chord: nerve chord containing a fluid-filled canal
-pharyngeal pouches
-postanal tail--> extends beyond anus
jawless fish
fish with..
-cylindrical body shape with smooth, scaless skin
-no jaws or paired fins
-scavengers
-extreme slime defense
cartilaginous fish
-includes sharks,skates, and rays
-skeleton of cartialge
-some are flat fishes that live partly buried in sand
-can sense electric currents and pressure
-have keen sense of smell
ray-finned fishes
fish with...
-paired fins supported by bony rays
-swim bladder for buoyancy
-streamlined shape
-bony scales for protection
lobe-finned fish
fish that has...
-evolved into amphibians
-coelacanths are living fossils
-has fleshy appendages
-most have longs
amphibians
-includes salamanders, toads, and newts
-tetrapods
-ears
-larynx for vocalization
-larger brain (relative to body size)
-small lungs in adults
-larval stage in water, adult stage on land
-reproduction in water
reptiles
-vertebrates that live on land
-scales cover body
-lay eggs
-cold blooded
mammals
-evolved from reptiles
-body hair (endothermic)
-milk-producing mammary glands
-very efficient respiratory and circulatory systems
-high level of care for the young