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157 Cards in this Set

  • Front
  • Back
what is pili?
a surface appendage in certain bacteria that functions in adherence and the transfer of DNA during conjugation
what is capsule?
a sticky layer that surrounds the cell walls of some bacteria, protecting the cell surface and sometimes helping to glue the cell to surfaces
what is gram-positive?
the group of bacteria with simpler ell walls with a relatively large amount of peptidoglycan. are usually less toxic than gram-negative bacteria.
what is gram-negative?
the group of bacteria with a structurally more complex cell wall made of less peptidoglycan. often more toxic than gram-positive bacteria.
what is petidoglycan?
a polymer of modified sugars cross-linked by short polypeptides. found in cell walls.
what is taxis?
movement toward or away from a stimulus
what is nucleoid region?
the region in a prokaryotic cell consisting of a concentrated mass of DNA
what is binary fission?
the type of cell division by which prokaryotes reproduce. each dividing daughter cell receives a copy of the single parental chromosome.
what is transformation?
when a cell can absorb and integrate fragments of DNA from their enviroment
what is conjugation?
one cell directly transfers genes to another cell
what is transduction?
viruses transfer genes between prokaryotes
what is an endospore?
a thick-coated, resistant cell produced within a bacterial cell exposed to harsh conditions
what is antibiotic?
a chemical that kills bacteria or inhibits their growth
what are photoautotrophs?
photosynthetic organisms that harness light energy to drive the synthesis of organic compounds from carbon dioxide
what are chemoautotrophs?
organisms that need only CO2 as a carbon source, but obtain energy by oxidizing inorganic substances
what are photoheterotrophs?
organisms that use light to generate ATP but obtain their carbon in organic form
what are chemoheterotrophs?
organisms that must consume organic molecules for both energy and carbon
what is nitrogen fixation?
the assimilation of atmospheric nitrogen by certain prokaryotes into nitrogenous compounds that can be directly used by plants
what is an obligate aerobe?
an organism that requires oxygen for cellular respiration and cannot live without it
what is an obligate anaerobe?
an organism that cannot use oxygen and is poisoned by it.
what is a facultative anaerobe?
an organism that will use oxygen if it is present but can also grow by fermentation in an anaerobic enviroment
what is anaerobic respiration?
the use of inorganic molecules other than oxygen to accept electrons at the "downhill" end of electron transport chains
what are decomposers?
any saprotrophic fungi and bacteria that absorb nutrients from nonliving organic material such as corpses, fallen plant material, and the wastes of living organisms, and convert them into inorganic forms
what is symbiosis?
an ecological relationship between organisms of two different species that live together in direct contact.
what is a host?
the larger participant in a symbiotic relationship, serving as home and feeding ground to the symbiont
what is commensalism?
a relationship where one symbiont receives benefits while the other is not harmed or helped by the relationship
what is parasitism?
where one symbiont benefits at the expense of the host
what is mutualism?
relationship between organisms where both symbionts benefit
what is opportunistic?
describes organisms that take advantage of a situation
what is Koch's postulates?
a set of four criteria for determining whether a specific pathogen is the cause of a disease
what is an exotoxin?
a toxic protein secreted by a bacterial cell that produces specific symptoms even in the absence of a bacterium
what is an endotoxin?
a component of the outer membranes of certain gram-negative bacteria responsible for generalized symptoms
what is bioremediation?
the application to remove pollutants from air, water, and soil
what is the endoplasmic reticulum?
the "highway" of the cell. either rough ribosome-studded) or smooth (ribosome-free)
what is the function of centrioles?
pulls chromosomes apart in animal cell division, are involved in the distribution of chromosomes during nuclear division
what is a vacuole?
deals with water regulation
what is the mitochondrion?
the powerhouse
what is the function of the golgi apparatus?
it is like the post office, puts "zip codes" of proteins to signal where they should be sent
what does the peroxisome do?
what does the nucleolus do?
manufactures ribosomes
what does the chloroplast do?
regulates energy, fixes CO2, and has to do with photosynthesis
what is the function of the cell wall (in plants)?
protects the cell, maintains its shape, and prevents excessive water intake, supports the plant against the force of gravity
what is the primary cell wall?
a relatively thin and flexible layer first secreted by a young plant cell
what is the extracellular matrix?
the substance in which animal tissue cells are embedded consisting of protein and polysaccharides
what is collagen?
a glycoprotein in the extracellular matrix of animal cells that forms strong fibers, found extensively in connective tissue and bone
what is proteoglycan?
a glycoprotein in the extracellular matrix of animal cells, rich in carbohydrates
what is fibronectin?
a glycoprotein that helps cells attach to the extracellular matrix
what is integrin?
receptor proteins built into the plasma membrane that interconnect the extracellular matrix and the cytoskeleton
what are plasmodesmata?
channels allowing cyotol to pass between cells
what is a tight junction?
a type of intercellular junction in animal cells that prevents the leakage of material between cells
what are desmosomes?
anchoring junctions that fasten cells together into strong sheets
what are gap junctions?
communicating junctions that provide cytoplasmic channels between adjacent cells
what are chromosomes?
a threadlike, genecarrying structure found in the nucleus. each chromosome consists of one very long DNA molecule and associated proteins
what are somatic cells?
body cells, the human body has 46 chromosomes
what are gametes?
sex cells, humans have 23 chromosomes, half the number in a somatic cell
what are sister chromatids?
replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II
what is the centromere?
the centralized region joining two sister chromatids
what is mitosis?
a process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. conserves chromosome number by equally allocating replicated chromosomes to each of the daughter nuclei
what is cytokinesis?
the division of the cytoplasm to form two separate daughter cells immediately after mitosis
what is meiosis?
a two-stage type of cell division in sexually reproducing organisms that results in cells with half the chromosome number of the original cell
what is prophase?
the first subphase of mitosis, in which the chromatin is condensing and the mitotic spindle begins to form, but the nucleolus and nucleus are still intact
what is metaphase?
the third substance of mitosis, in which the spindle is complete and the chromosomes, attached to microtubules at their kinetochores, are all aligned at the metaphase plate?
what is anaphase?
the fourth subphase of mitosis, in which the chromatids of each chromosome have separated and the daughter chromosomes are moving to the poles of the cell
what is telophase?
the fifth and final subphase of mitosis, in which the daughter nuclei are forming and cytokinesis has typically begun
what is a kinetochores?
a specialized region on the centromere that links each sister chromatid to the mitotic spindle
what is cleavage furrow?
the first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase
what is the cell plate?
a double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis
what is meiosis I?
the first cell division of a two-stage process. the results = half the number of chromosomes from original cells
what is meiosis II?
the second round of a two-stage process of cell division. resulting in half number of chromosomes than original
what is synapsis?
when homologous chromosomes pair up in prophase I
what is absorption (ex. fungi)?
the uptake of small nutrient molecules by an organism's own body; the third main stage of food processing, following digestion
what is a saprobic fungi?
absorb nutrients from nonliving organisms
what is a parasitic fungi?
absorb nutrients from the cells of living hosts
what is mutualistic fungi?
absorbs nutrients from a host organism, but they reciprocate with functions that benefit their partner in some way
what is hypha?
a filament that collectively makes up the body of a fungus
what is a mycelium?
the densely branched network of hyphae in a fungus
what are exoenzymes?
powerful hydrolic enzymes secreted by the fungus, digest food outside its body to simpler compounds that the fungus can absorb and use
what is coenocytic fungi?
fungi that lacks septa, consisting of of a continuous cytoplasmic mass with hundreds or thousands of nuclei
what is karyogamy
fusion of haploid nuclei contributed by two parents
what is plasmogamy?
fusions of the cytoplasm of cells from two individuals
what is dikaryotic?
a mycelium with two haploid nuclei per cell, one from each parent
what is a chytrid?
mainly aquatic primitive fungi that form uniflagellated spores
what is mycorrhizae?
a mutualistic association of plant root and fungus
what are ascocarps?
macroscopic fruiting bodies of sac fungi
what is an asci?
a saclike spore capsule located at the tip of the ascocarp in dikaryotic hyphae
what are ascocarps?
macroscopic fruiting bodies of sac fungi
what is the basidium?
a reproductive appendage that produces sexual spores on the gills mushrooms
what is club fungus?
a common name for the members of the phylum Basiodiomycota. name comes from clublike shape of the basidium
what are basidiocarps?
elaborate fruiting bodies of a dikaryotic mycelium of a club fungus
what is an imperfect fungi?
fungi that cannot be classified. they have temporary classifications until a mycologist can find their sexual stage and reclassify them according to the sexual stage
what are yeasts?
unicellular fungi that inhabit liquid or moist habitats
what are lichens?
a symbiotic association of millions of photosynthetic microorganisms held in a mesh of fungal hyphae
what are soredia?
small clusters of lichen hyphae with embedded algae
what is mycosis?
a fungal infection
what is a sporophyte?
the diploid individual that produces haploid spores by meiosis
what is a gametophyte?
a haploid individual that produces gametes by mitosis that fuse to form a diploid zygote
what is a bryophyte?
a nonvascular plant that inhabits the land but lacks any of the terrestrial adaptations of vascular plants
what is vascular tissue?
plant tissue consisting of cells joined into tubes that transport water and nutrients throughout the plants body
what are pteridiophytes?
seedless plants
what is a seed?
an adaptation for terrestrial plants consisting an embryo packaged along with a store of food within a resistant coat
what is a gymnosperm?
a vascular plant that bears naked seed -- seed not enclosed in specialized chambers
what are angiosperms?
flowering plants
what is rosette cellulose-synthesizing complexes?
rose-shaped array of proteins that synthesize the cellulose microfibrils of the cell walls of charophyceans and land plants
what is a peroxisome?
a microbody containing enzymes that transfer hydrogen from various substrates to oxygen, producing and then degrading hydrogen peroxide
what is phragmoplast?
an alignment of cytoskeletal elements and golgi-derived vesicles across the midline of a dividing plant
what are apical meristems?
localized regions of cell division at the tips of shoots and roots
what is an embryophyte?
another name for land plants
what are placental transfer cells?
plant cells that enhance the transfer of nutrients from parent to embryo
what is alternation of generations?
a life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular form, the gametophyte
what is a sporangium (plural, sporangia)?
a capsule in fungi and plants in which meiosis occurs and haploid spores develop
what are spore mother cells?
the cells that undergo meiosis and generate haploid spores within a sporangium
what is sporopollenin?
a polymer that is the most durable organic material known and covers spores
what is gametangium (plural, gametangia)?
the reproductive organ of bryophytes, consisting of the male antheridium and female archegonium; a multichambered jacket of sterile cells in which gametes are formed
what is the archegonium?
female gametangium
what is the antheridia?
male gametangia
what is the cuticle?
a waxy covering on the surface of stems and leaves that acts as an adaptation to prevent desiccation in terrestrial plants
what is stomata?
pores in the epidermis of leaves and other photosynthetic organs that allow the exchange of carbon dioxide and oxygen between the outside air and the leaf interior
what is the xylem?
tube-shaped dead cells that carry water and minerals up from roots
what is phloem?
a living tissue in which nutrient-conducting cells arranged into tubes distribute sugars, amino acids, and other organic products
what is a protonema?
a mass of green, branched, one-cell thick filaments that makes up the gametophyte
what is a gametosphore?
the mature gamete-producing structure of a gametophyte body of a moss
what are rhizoids?
long tubular single cells or filaments of cells that anchor bryophytes to the ground
what are megaphylls?
the larger leaves of modern vascular plants served by a highly-branched vascular system
what are microphylls?
the small leaves of lycophytes that have only single, unbranched veins
what is a heterosporous sporophyte?
sporophyte that produces two kinds of spores
what are megaspores?
sporophytes develop into females gametophytes
what are microspores?
sporophytes that develop into male gametophytes
what are homosporous sporophytes?
sporophytes that produces a single type of spore
what is a sporophyll?
modified leaves that bears sporangia
what are sori?
clusters of fern sporangia on the backs of green leaves or on special, nongreen leaves (sporophylls). their unique pattern helps in identifying them
what is integument?
layers of sporophyte tissue that contribute to the structure of an ovule of a seed plant
what is an ovule?
a structure that develops in the plant ovary and contains the female gametophyte
what is pollination?
the placement of pollen onto the stigma of a carpel by wind or animal carriers, a prerequisite to fertilization
what are progymosperms?
an extinct group of plants that is probably ancestral to gymnosperms and angiosperms
what is a conifer?
a gynosperm whose reproductive structure is the cone
what is dicot?
a subdivision of flowering plants whose members possess two embryonic seed leaves, or cotyledons
what is monocot?
a subdivision of flowering plants whose members possess one embryonic seed leaf
what are eudicots?
a large subgroup of traditionally dicot angiosperms including roses, peas, buttercups, sunflowers, oaks, and maples
what is a flower?
in an angiosperm, a short stem with four sets of modified leaves, bearing structures that function in sexual reproduction
what is a sepal?
a whorl of modified leaves in angiosperms that encloses and protects the flower bud before it opens
what is a petal?
a modified leaf of a flowering plant, helps with reproduction
what is stamen?
the pollen-producing male reproductive organ of a flower, consisting of a an anther and filament
what are carpals?
female sporophylls that produce megaspores and their products, female gametophytes
what is the stigma?
the sticky part of a flower's carpel, which traps pollen grains
what is the style?
the stalk of a flower's carpel, with the ovary at the base and the stigma at the top
what is the ovary?
the portion of a carpel in which the egg-containing ovules develop
what is a fruit?
a mature ovary of a flower that protects dormant seeds and aids in their dispersal
what is a pericarp?
the thickened wall of a fruit
what are simple fruits?
fruits derived from a single ovary
what is an aggregate fruit?
fruit resulting from a single flower with several carpals
what is a multiple fruit?
a fruit such as pineapple that develops from an inflorescence, a group of flowers tightly clustered together
what are pollen grains?
the structures that contain the immature male gametophytes
what is the embryo sac?
the female gametophyte of angiosperms, formed from the growth and division of the megaspore into a multicellular structure with eight haploid nuclei
what is cross-pollination?
the transfer of pollen from flowers of one plant to flowers of another plant of the same species
what is double fertilization?
a mechanism of fertilization in angiosperms, in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm
what are cotyledons?
the one (monocot) or two (dicot) seed leaves of an angiosperm embryo
what is an endosperm?
a nutrient rich tissue formed by the union of a sperm cell with two polar nuclei during double fertilization, which provides nourishment to the developing embryo in angiosperm seeds