MVHS APBiology Ch. 27 Vocabulary
Terms
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- single-celled organisms that lack a true nucleus and membrane-bound organelles
- prokaryotes
- the taxonomic level above kingdom
- domain
- the three domains of living things
- Bacteria, Archaea, Eukarya
- spherical-shaped prokaryotes
- cocci
- rod-shaped prokaryotes
- bacilli
- spiral-shaped prokaryotes
- helical
- a substance made up of polymers of modified sugars cross-linked by short polypeptides; found in cell walls of Bacteria but not Archaea
- peptidoglycan
- bacteria with simpler cell walls and high levels of peptidoglycan
- Gram-positive
- bacteria with complex cell walls, lipopolysaccharides, and low levels of peptidoglycan
- Gram-negative
- these cells stain light red with Gram stain
- Gram-negative
- these cells stain dark purple with Gram stain
- Gram-positive
- a protective sticky layer outside the cell wall of many prokaryotes
- capsule
- surface appendages/extensions that allow prokaryotes to adhere to one another or other surfaces
- pili
- movement toward or away from a stimulus
- taxis
- the region in prokaryotic cell where DNA is concentrated
- nucleoid region
- How would you describe the DNA of prokaryotes?
- a single, double-stranded, circular molecule
- small rings of DNA that prokaryotes can take in from their environment or other prokaryotes
- plasmids
- occurs when prokaryotic cells take up genes from their environment
- transformation
- the direct transfer of genes from one prokaryote to another
- conjugation
- occurs when viruses transfer genes from one prokaryote to another
- transduction
- resistant prokaryotic cells in a "dormant" state; can withstand extreme environmental conditions
- endospores
- chemicals that inhibit the growth of microorganisms
- antibiotics
- photosynthetic organisms
- photoautotrophs
- obtain energy using carbon dioxide as a carbon source and oxidizing inorganic substances
- chemoautotrophs
- use light to generate ATP but require organic carbon sources
- photoheterotrophs
- must consume organic molecules for both energy and carbon
- chemoheterotrophs
- decomposers that absorb their nutrients from dead organic matter
- saprobes
- absorb nutrients from the body fluids of living hosts
- parasites
- the conversion of atmospheric nitrogen to ammonia (a useable nitrogen source)
- nitrogen fixation
- use oxygen for cellular respiration and can't live without it
- obligate aerobes
- will use oxygen if present but can also perform fermentation in anaerobic situations
- facultative anaerobes
- organisms that are poisoned by oxygen
- obligate anaerobes
- a process in which inorganic molecules other than oxygen serve as final electron acceptors
- anaerobic respiration
-
Which is the most parsimonious hypothesis:
1) photosynthesis evolved many times or
2) photosynthesis evolved once? - photosynthesis evolved once (this hypothesis is the simplest, requiring the least number of evolutionary changes)
- SSU-rRNA
- small-subunit ribosomal ribonucleic acid
- regions of SSU-rRNA in a group of organisms that have unique nucleotide sequences due to common ancestry
- signature sequences
- "lovers" of extreme environments
- extremophiles
- organisms that use carbon dioxide to oxidize hydrogen, producing methane as a waste product
- methanogens
- these live in very saline environments
- halophiles
- photosynthetic pigment found in halophile colonies
- bacteriorhodopsin
- these thrive in hot environments (60-80 degrees Celsius is usually optimum)
- thermophiles
- Domain of prokaryotes that contain peptidoglycan, one kind of RNA polymerase, and unbranched membrane hydrocarbons
- Bacteria
- Domain of prokaryotes that contain no peptidoglycan, several kinds of RNA polymerase, introns, and histones
- Archaea
- Which domain of prokaryotes is not susceptible to streptomycin and chloramphenicol?
- Archaea
- To which domain do the great majority of prokaryotes belong?
- Bacteria
- This major clade of Bacteria is gram-negative and includes 5 diverse subgroups
- Proteobacteria
- This major clade of Bacteria lack peptidoglycan and are obligate intracellular parasites
- Chlamydias
- This major clade of Bacteria are helical; many are free-living but some are pathogens
- Spirochetes
- This major clade of Bacteria includes all gram-positive forms and a few gram-negative relatives
- Gram-positive Bacteria
- This major clade of Bacteria are the only prokaryotes that perform plantlike (oxygenic) photosynthesis
- Cyanobacteria
- organisms that break down the organic molecules in dead organic material and wastes
- decomposers
- an ecological relationship between organisms of different species in direct contact with one another
- symbiosis
- the larger of 2 organisms in a symbiotic relationship
- host
- a symbiosis in which both organisms benefit
- mutualism
- a symbiosis in which one organism receives benefits while neither helping nor harming the other organism
- commensalism
- a symbiosis in which one organism benefits at the expense of another
- parasitism
- an organism that benefits at the expense of its host
- parasite
- pathogens that are not normally residents of a host but can cause illness in a weakened host
- opportunistic pathogens
- What are Koch's postulates for identifying a pathogen as the cause of a disease?
-
1) find the same pathogen in each diseased organism
2) isolate the pathogen from the organism and grow it in pure culture
3) transfer the pathogen from the culture to an organism, inducing the disease
4) isolate the same pathogen from the diseased experimental organism - proteins secreted by prokaryotes that produce disease symptoms in other organisms
- exotoxins
- components of the outer membranes of gram-negative bacteria that cause disease symptoms in other organisms
- endotoxins
- the use of organisms to remove pollutants from water, air or soil
- bioremediation
- this is the most common mechanism of movement among prokaryotes
- flagella
- Which group of helix-shaped Bacteria move by rotating filaments embedded in their cell walls?
- Spirochetes
- What is the name for specialized nitrogen-fixing cells in cyanobacteria such as Anabaena?
- heterocysts