| A | B |
|---|
| methanogens | archaebacteria that live deep in swamp mud and make methane (CH4) gas |
| extremophiles | organisms that live under extreme conditions (e.g., very hot, very salty, enormous pressure, very acidic, or very basic) |
| halophiles | archebacteria that live in extremely salty water |
| eubacteria | "true" bacteria that have cell walls made of peptidoglycan |
| peptidoglycan | a weblike molecule made of polysaccharides cross-linked by short peptide bridges |
| archaebacteria | prokaryotes whose ribosomes resemble those of eukaryotes, and whose genes are interrupted by introns (intervening sequences), just like eukaryotes |
| autotroph | an organism that makes its own food |
| heterotroph | an organism that cannot make its own food -- it must eat |
| prokaryotic | cells lack nucleus and internal membranes |
| eukaryotic | cells have a nucleus and internal membranes |
| development | the process by which a zygote (fertilized egg) becomes a complex multicellular organism |
| differentiation | the process by which cells develop a specialized form and function |
| tissue | a group of cells with similar structure and function |
| organ | a group of tissues that work together to perform a function (e.g., a heart, a kidney, a liver) |
| organ system | A collection of organs that together carry out a major body function (e.g., the circulatory system = the heart, blood vessels, and blood) |
| protists | eukaryotes that are neither fungi, plants, nor animals (e.g., algae or amoebas) |
| fungi | heterotrophic eukaryotic organisms that have cell walls made of chitin (example: mushrooms) |
| hyphae | slender strands of a fungus |
| vascular tissue in plants | specialized cells that transport water and nutrients |
| seed | a plant embryo enclosed in a protective coat |
| nonvascular plants | Plants lacking vascular tissue (e.g., mosses) |
| seedless vascular plants | plants with vascular tissue, but no seeds (e.g., ferns) |
| gymnosperms | nonflowering seed plants: vascular plants that produce seeds but no flowers (e.g., pine trees) |
| angiosperms | flowering seed plants: vascular plants that produce flowers and seeds (e.g., roses, grasses, oak trees) |
| invertebrates | animals lacking a backbone |
| vertebrates | animals with a backbone |
| sponges | primitive animals without tissues |
| mollusks | snails, clams, octopuses, and squid |
| arthropods | insects, spiders, crustaceans |
| echinoderms | starfish, sea urchins, sand dollars |
| chordates | the phylum that includes all vertebrates |
| viruses | very small disease-causing agents that can infect living cells |
| pathogen | a disease-causing agent (e.g., a virus or a bacteria) |
| capsid | the protein coat of a virus |
| bacteriophage | a virus that infects bacteria |
| glycoproteins | proteins with attached carbohydrate molecules |
| lytic cycle | the viral life cycle leading to cell destruction: the virus infects the cell, replicates, and lyses the cell (bursts it open to release the new viruses) |
| lysogenic cycle | the viral life cycle in which the virus integrates into the host cell's DNA |
| provirus | a virus that is integrated into a host cell's DNA |
| prion | a disease-causing protein |
| viroid | a disease-causing single-stranded RNA with no capsid (viroids can infect plants) |
| bacillus | a rod-shaped bacterial cell |
| coccus | a round bacterial cell |
| spirillum | a spiral (helical) bacterial cell |
| antibiotics | chemicals that interfere with life processes in bacteria |
| spore | a reproductive cell or multicellular structure that can survive harsh environmental conditions |
| endospore | a thick-walled protective spore that allows bacteria to survive harsh environmental conditions |
| conjugation | bacterial sex: a process in which two bacteria exchange DNA |
| pili (singular = pilus) | short appendages that allows bacteria to stick to things |
| anaerobic | lacking oxygen |
| aerobic | with oxygen |
| toxin | a poisonous (toxic) chemical |
| Alexander Fleming in 1928 | The discoverer of antibiotics: he noticed bacteria would not grow near a fungus |
| fermentation | the breakdown of carbohydrates by enzymes, bacteria, yeasts, or molds in the absence of oxygen (used to prepare beer, cheese, sauerkraut, etc.) |
