45 terms

IHA Freshman Biology I Honors-Classification/Viruses/Prokaryotes (Beginning)

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classification
the arrangement of organisms into orderly groups based on their similarities
taxonomy
classification (arrangement of organisms into orderly groups based on their similarities)
taxonomists
scientists that identify and name organisms
misnomer
misleading name
Aristotle
first taxonomist; divided plants and animals and subdivided them by their habitat (land, sea, or air)
John Ray
botanist; first man to use Latin for naming; names were long descriptions telling everything about plant
botanist
person who studies plants
Carolus Linnaeus
18th century taxonomist; classified organisms by their structure; developed naming system still used today (binomial nomenclature); "Father of Taxonomy"
binomial nomenclature
Genus + species naming system
taxon
a category into which related organisms are placed
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
hierarchy of groups from broadest to most specific; Dear King Phil Came Over For Great Soup
Archaea, Bacteria, Eukarya
3 Domains; unicellular or multicellular
Archaea
Archaebacteria; 1st cells to evolve; live in HARSH environments
Bacteria
Eubacteria; some may cause disease; found in all habitats (except harsh ones); decomposers for environment
Eukarya
4 Kingdoms: Protista, Fungi, Plantae, Animalia
Protista
most unicellular; some autotrophic, some heterotrophic; aquatic
Fungi
multicellular; absorptive heterotrophs; cell walls made of chitin
absorptive heterotrophs
digest food outside their body and then absorb it
Plantae
multicellular; autotrophic; perform photosynthesis; cell walls made of cellulose
Animalia
multicellular; ingestive heterotrophs; feed on plants or animals
ingestive heterotrophs
consume food and digest it inside their bodies
homologous structures
basis for modern taxonomy; same structure, different function
cladogram
diagram showing how organisms are related based on shared, derived characteristics; an evolutionary tree made using cladistics
phylogeny
the evolutionary history for a group of species
clade
a group of species that shares a common ancestor
derived characteristic
traits shared in different degrees by clade members; basis of arranging species in cladogram; more closely related species share more of these
nodes
represent the most common ancestor of a clade
dichotomous keying
used to identify organisms; characteristics given in pairs; step-by-step guide to help identify an organism; follows a series of choices that lead you to the organism's name
mitochondrial DNA
used to study closely related species; mutation rate is 10 times faster than nuclear DNA; passed down unshuffled from mother to offspring
ribosomal RNA
used to study distantly related species; many conservative regions; lower mutation rate than most DNA
virus
nonliving particle made of proteins, nucleic acids, sometimes lipids; requires a host cell to replicate; don't: contain a nucleus or cytoplasm, eat, grow, carry on respiration, or perform other biological functions
structure of virus
small, capsid, and sometimes additional envelope; nucleic acids in capsid; tail fibers for attachment to host cell; species specific;
capsid
protein coat surrounding a virus; inner core of nucleic acid is inside this; contains nucleic acids
bacteriophages
viruses that infect bacteria
reproduction of a virus
only within a cell; don't have: enzymes for metabolism, ribosomes, the equipment to make proteins
lytic infection
virus enters a bacterial cell, makes copies of itself, and causes the cell to burst
lysogenic infection
a host cell is not immediately taken over; viral nucleic acid is inserted into host cell's DNA, viral DNA is copied along w/ host DNA w/o damaging the host, viral DNA multiplies as host cells multiply, prophage may remain part of DNA of host cell for many generations, influences from environment trigger prophage to become active, and finally removes itself from the host cell DNA, directs the synthesis of new virus particles, and now becomes an active lytic infection
prophage
bacteriophage DNA that becomes embedded in the bacterial host's DNA
common cold
attack w/ very simple, fast acting infection; capsid settles on a cell and is brought inside, where viral protein makes new copies of viral RNA; host cell's ribosomes mistake viral RNA for host's own mRNA and translate it into capsids and other proteins
retroviruses
genetic information flows in reverse direction; has enzyme: reverse transcriptase (transcribes DNA from and RNA template); newly made DNA then integrates as a provirus into nucleus of animal cell; host's RNA polymerase transcribes viral DNA into RNA molecules
HIV
deadly disease called acquired immune deficiency syndrome (AIDS) is caused by an RNA virus; retrovirus; when retrovirus infects a cell, it makes a DNA copy of its RNA; the copy inserts itself into the DNA of the host cell
viruses and cells
parasites (dependent upon other living organisms for existence); must infect living cells in order to grow and reproduce; after infecting living cells, viruses can: reproduce, regulate gene expression, evolve (see chart on PPT or in notes for differences)
prokaryotes
unicellular organisms that lack a nucleus; smallest and most abundant microorganisms on Earth; have DNA, but their DNA is not found on a membrane-bound nuclear envelope (located in the cytoplasm);
prokaryotic cell walls
maintain cell shape, provide physical protection, and prevent the cell from bursting in a hypotonic environment
Archaea prokaryotes
look very similar to bacteria (both equally small, lack nuclei, have cell walls); also very different (walls of ___ lack peptidoglycan, membranes contain different lipids, DNA sequences of key ___ genes are more like those of eukaryotes than those of bacteria); live in harsh environments; major life form in oceans