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