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63 Cards in this Set
- Front
- Back
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• Prokaryote shapes
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o Cocci- Spheres
o Bacilli- rods o Spiral |
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• Prokaryotic cell walls
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o Maintains shape, structure
o Protection o Prevents cell from bursting or shriveling in hyper/hypo tonic environments o Made of cellulose or chitin o Peptidoglycan • In most bacterial cell walls • Network of modified sugar polymers cross linked by short polypeptides • Encloses entire bacterium and anchors other molecules that extend from its surface |
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• Gram positive bacteria
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o Have simpler walls with large amount of peptidoglycan
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• Gram negative bacteria
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o Have less peptidoglycan
o Structurally more complex o Has an outer membrane of lipopolysaccharides (carbs bounded to lipids) • Lipopolysaccharides are often toxic, secrete toxins o More deadly than gram positive bacteria o More resistant to antibiotics b/c of strong outer membrane |
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• How do antibiotics work?
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o They inhibit the formation of peptidoglycan (which forms the cell wall)
o Work well in gram positive bacteria o Only destroy bacteria b/c human cells don’t have peptidoglycan |
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• Capsule
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o Covers cell wall of prokaryotes
o Sticky layer of polysaccharide or protein o Enables bacteria to adhere to things o Serve as protection against immune systems |
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• Fimbriae and Pili
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o Hair like structures that enable bacteria to adhere to substrate or other bacteria
o Fimbriae are more numerous and shorter than Pili |
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• Flagella and Cilia
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o Flagella are most common
• Can have one or more flagella o Prokaryote flagella are thinner and shorter than eukaryotic flagella o Help bacteria move |
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• Taxis
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o Prokaryotes exhibit taxis in a heterogeneous environment
o Taxis→ ability to respond to stimuli o Bacteria will respond to stimuli |
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• Membrane function in prokaryotes
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o Cellular membrane can preform cellular respiration, photosynthesis
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• Nucleoid region
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o Region where the prokaryote’s DNA is located
o Prokaryote’s DNA is located in the prokaryotic chromosome o Bacteria have a single chromosome in the nucleoid region o All essential functions are coded in the bacterial chromosome |
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• Plasmids
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o Smaller rings of DNA in bacteria
o Consist of only a few genes o Provide resistance to antibiotics, direct the metabolism of rarely encountered nutrients o Plasmids contain optional DNA, all essential bacteria functions are coded in the prokaryotic chromosome o Can replicate independently o Bacteria transfer plasmids through conjugation- helps their survival by exchanging genes |
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• Endospores
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o Certain bacteria form resistant cells called endospores when an essential nutrient is lacking in the environment
o Original cell replicates its chromosome and surrounds it with a tough wall (forming an endospore) o Metabolism within the endospore ceases o The rest of the cell disintegrates, leaving the endospore behind o Endospores are so durable they can survive in boiling water o Endospores help bacteria survive- its like hibernation for bacteria |
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• Phototrophs
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• Phototrophs→ obtain energy from light
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• Chemotrophs
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• Chemotrophs→ obtain energy from chemicals
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• Autotrophs
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• Autotrophs→ organisms that only need CO2 to obtain carbon
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• Heterotrophs
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• Heterotrophs→ require an organic nutrient like glucose to obtain carbon
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• Photoautotrophs
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• Photoautotrophs→ photosynthetic organisms that capture light energy and use it to drive the synthesis of organic compounds from CO2
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• Chemoautotrophs
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• Chemoautotrophs→ need only CO2 as a carbon source, oxidize inorganic substances for energy
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• Photoheterotrophs
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• Photoheterotrophs→ use light for energy, use organic forms of carbon as a carbon source
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• Chemoheterotrophs
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• Chemoheterotrophs→ use organic molecules for both energy and for carbon
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• Obligate aerobes
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o Use O2 for cellular respiration and cannot grow without it
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• Facultative anaerobes
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o Use O2 if it is present but can also grow by fermentation in an anaerobic environment
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• Obligate anaerobes
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o Poisoned by O2
o Some live exclusively by fermentation o Some live by extracting chemical energy by anaerobic respiration |
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• Nitrogen fixation
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o Certain prokaryotes convert N2 into NH3 (ammonia)
o Cyanobacteria are nitrogen fixers |
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• Metabolic cooperation in bacteria
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o Anabaena lives in colonies
o Some bacteria carry out only photosynthesis, some bacteria carry out only nitrogen fixation o Intercellular connections allow bacteria to exchange carbohydrates and nitrogen with each other o This way, the entire colony can fix nitrogen and carry out photosynthesis |
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• Biofilms
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o Metabolic cooperation occurs in surface coating colonies known as biofilms
o Colony cells secrete signaling molecules that recruit nearby cells, causing the colony to grow o Produce proteins that adhere the cells to the substrate and to one another |
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• Prokaryotic phylogeny
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o Prokaryotes are extremely diverse
o Horizontal gene transfer (bacterial transfer of plasmids) is very significant in the evolution of prokaryotes • Prokaryotes have acquired genes from distantly related species in this way • Constant transfer of genes diversifies prokaryotes |
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• Archaea
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o No peptidoglycan
o Has some branched hydrocarbons for membrane lipids o Several kinds of RNA polymerase o Methionine (start amino acid codon thing) o Has some introns in its genes o Doesn’t respond to antibiotics o Has histones o Circular chromosome o Some species can grow at temperatures greater than 100 celsius |
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• Bacteria
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o Has peptidoglycan
o Has unbranched hydrocarbons for membrane lipids o One kind of RNA polymerase o Formyl-Methionine (start amino acid codon thing) o Doesn’t have introns in its genes o Negatively affected by antibiotics o No histones o Circular chromosomes o Can’t survive at temperatures greater than 100 celsius |
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• Eukarya
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o Has nuclear envelope and membrane enclosed organelles
o No peptidoglycan o Has unbranched hydrocarbons for membrane lipids o Several kinds of RNA polymerase o Methionine (start amino acid codon thing) o Has introns in its genes o Doesn’t respond to antibiotics o Has histones o No circular chromosomes o Can’t survive at temperatures greater than 100 celsius |
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• Extremophiles
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o Archaea bacteria that live in extreme conditions
o Oldest prokaryotes classified in the domain archaea o Extreme thermophiles, halophiles, methanogens |
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• Extreme thermophiles
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o Archaea bacteria that thrive in very hot environments
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• Extreme halophiles
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o Archaea bacteria that thrive in highly saline environments
o Very salty places |
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• Methanogens
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o Use CO2 to oxidize H2 and release methane as a waste product
o Poisoned by O2 |
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• Proteobacteria
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o Large and diverse clade of gram negative bacteria
o Includes photoautotrophs, chemoautotrophs, and heterotrophs o Either anaerobic or aerobic o Five subgroups of proteobacteria • Alpha, beta, gamma, delta, epsilon |
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• Chlamydias
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o Parasites that survive only within animal cells
o Depend on host for resources like basic ATP o Lack peptidoglycan |
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• Spirochetes
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o Helical heterotrophs
o Some are notorious pathogenic parasites like syphilis and lyme disease |
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• Cyanobacteria
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o Photoautotrophs
o Only prokaryotes with plant like oxygen generating photosynthesis o Chloroplasts likely evolved from cyanobacteria |
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• Decomposers
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o Bacteria function as decomposers
o Without decomposers, chemical cycling would cease and live would end on earth |
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• Symbiosis
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o An ecological relationship between organisms of different species that are in direct contact
o Bacteria have symbiotic relationships with most organisms (we have E coli in our digestive tract) |
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• Host
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• Host: the thing the symbiont lives in in a symbiotic relationship
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• Mutualism
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• Mutualism: both benefit from the relationship
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• Commensalism
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• Commensalism: one benefits while the other is not affected
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• Parasitism
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• Parasitism: one benefits and the other is harmed
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• Exotoxins
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o Proteins secreted by prokaryotes
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• Endotoxin
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o Toxic Lipopolysaccharide components of the outer membrane of gram negative bacteria
o Released only when the bacteria die and their cell walls break down |
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• Bioremediation
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o Use of organisms to remove pollutants from soil air or water
• Bacteria help clean up pollution o Prokaryotes are very useful |
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• Protists
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o Unicellular or multicellular eukaryotes
o most nutritionally diverse: photoautotrophs, heterotrophs, mixotrophs (both heterotroph and photoautotroph) o Very diverse: some are more closely related to plants, animals, or fungi o Diverse habitats |
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• Endosymbiotic theory
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o Earliest eukaryotes acquired mitochondria by engulfing a bacteria
o Organelles originated from symbiotic relationship between a eukaryote and a prokaryote o Primary endosymbiosis: eukaryote engulfs prokaryote o Secondary endosymbiosis: the same eukaryote engulfs another prokaryote |
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• Diplomonads
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o No plastids
o No DNA, ETC, or enzymes in mitochondria o Anaerobic o Have two equal sized nuclei o Multiple flagella o Ex: Giardia |
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• Parabasalids
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o Ex: T vaginalis
o No plastids o No DNA, ETC, or enzymes in mitochondria o Anaerobic |
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• Euglenozoa
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o Have flagella with unique internal structure
• Has a spiral or crystalline rod of unknown function inside flagella o 2 kinds: Kinetoplastids and Euglenids |
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• Kinetoplastids
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o Single large mitochondrion that contains an organized mass of DNA called kinetoplast
o Free living consumers of prokaryotes in freshwater, marine, moist terrestrial ecosystems o Flagella • Has a spiral or crystalline rod of unknown function inside the flagella o Ex: Trypanosoma (sleeping sickness) |
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• Euglenids
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o Have a pocket at one end of the cell where one or two flagella emerge
o Ex: Euglena (both photosynthetic and heterotrophic) |
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• Alveolates
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o Have membrane bounded sacs (alveoli) under plasma membrane
• Function is unknown o two groups: dinoflagellates and ciliates |
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• Dinoflagellates
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o Heterotrophic or phototrophic
o Most are unicellular, some are colonial o Internal cellulose plates reinforce cell wall o Have two flagella o Cause red tide when they “bloom” o Some release toxins that can poison animals o Some are bioluminescent |
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• Ciliates
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o Protists that use cilia to move/feed
o Have large macronuclei and small micronuclei o Some have oral groove, use cilia to sweep food into oral groove ex: paramecium |
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• Formation of cyst
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o Mosquito bites person and injects protest into person
o Protist goes into person’s liver cells, replicate, burst out, and penetrate the blood cells o Protist divides asexually in blood cells o Protest bursts out of blood cells o Mosquito bites person and picks up protest o Zygotes form in mosquito’s digestive tract o Zygotes form a cyst as they get bigger o Cyst bursts |
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• Conjugation and reproduction
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o Two cells align side by side and partially fuse
o Meiosis of micronuclei produces four haploid micronuclei in each cell o Cells exchange micronuclei o Cells separate o One micronuclei from each cell fuse together in each cell (now you have a diploid micronucleus) o Diploid micronucleus divides mitotically in each cell o Original macronucleus disappears in each cell o Four diploid micronuclei become one macronucleus, four diploid micronuclei remain micronuclei: in each cell o Cell splits to create four daughter cells |
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• Conjugation
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o Sexual process in which two individuals exchange haploid micronuclei
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• Diatoms
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o Type of Stramenopile
o Unicellular algae o Unique glass like wall made of hydrated silica embedded in an organic matrix o Very strong cell wall o Asexual reproducers o Major component of phytoplankton |
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• Red Algae/Green Algae
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o Closet relatives to land plants
o Red algae: • most abundant large algae in warm coastal waters • multicellular • red b/c of pigment phycoerythrin which masks green chlorophyll o Green algae • Chloroplasts • Closely related to land plants • Chlorophytes and charophyceans (two main groups) • |
