Vocabulary Flashcards
The X-shaped, microscopically visible region where crossing over has occurred earlier in prophase I between homologous nonsister chromatids.
Chiasmata
A light-capturing unit located in the thylakoid membrane of the chloroplast or in the membrane of some prokaryotes, consisting of a reaction-center complex surrounded by numerous light-harvesting complexes.
Photosystem
A circular flow of cytoplasm, involving interactions of myosin and *, that speeds the distribution of materials within cells.
actin filaments,
The collection of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles; includes the plasma membrane, the nuclear envelope, the smooth and rough endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, and vacuoles.
endomembrane system
The coupling of the “downhill” diffusion of one substance to the “uphill” transport of another against its own concentration gradient.
cotransport
Definition: An infolding of the inner membrane of a mitochondrion. The inner membrane houses electron transport chains and molecules of the enzyme catalyzing the synthesis of ATP (ATP synthase).
Term: crista (plural, cristae)
Definition: A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP.
Term: electron transport chain
Definition: The linkage of a mechanical, chemical, or electromagnetic stimulus to a specific cellular response.
Term: signal transduction
Definition: A netlike array of protein filaments that lines the inner surface of the nuclear envelope and
Term: nuclear lamina
Definition: An organism that carries out only fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it.
Term: obligate anaerobe
Definition: A nondividing state occupied by cells that have left the cell cycle, sometimes reversibly.
Term: G0 phase
Definition: All the organisms in a given area as well as the abiotic factors with which they interact; one or more communities and the physical environment around them.
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Term: ecosystem
Definition: Ribulose bisphosphate (RuBP) carboxylase-oxygenase, the enzyme that normally catalyzes the first step of the Calvin cycle (the addition of CO2 to RuBP). When excess O2 is present or CO2 levels are low, rubisco can bind oxygen, resulting in photorespiration.
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Term: rubisco
Definition: A transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration or electrochemical gradient.
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Term: ion channel
Definition: A network of microtubules, microfilaments, and intermediate filaments that extend throughout the cytoplasm and serve a variety of mechanical, transport, and signaling functions.
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Term: cytoskeleton
Definition: A structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle.
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Term: kinetochore
Definition: A plant in which the Calvin cycle is preceded by reactions that incorporate CO2 into a four-carbon compound, the end product of which supplies CO2 for the Calvin cycle.
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Term: C4 plant
Definition: A three-carbon carbohydrate that is the direct product of the Calvin cycle; it is also an intermediate in glycolysis.
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Term: glyceraldehyde 3-phosphate (G3P)
Definition: A plant that uses crassulacean acid metabolism, an adaptation for photosynthesis in arid conditions. In this process, CO2 entering open stomata during the night is converted to organic acids, which release CO2 for the Calvin cycle during the day, when stomata are closed.
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Term: CAM plant
Definition: The diffusion gradient of an ion, which is affected by both the concentration difference of an ion across a membrane (a chemical force) and the ion’s tendency to move relative to the membrane potential (an electrical force).
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Term: electrochemical gradient
Definition: A membranous sac formed by phagocytosis of microorganisms or particles to be used as food by the cell.
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Term: food vacuole
Definition: A route of electron flow during the light reactions of photosynthesis that involves both photosystems (I and II) and produces ATP, NADPH, and O2. The net electron flow is from H2O to NADP+.
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Term: linear electron flow
Definition: An adaptation for photosynthesis in arid conditions, first discovered in the family Crassulaceae. In this process, a plant takes up CO2 and incorporates it into a variety of organic acids at night; during the day, CO2 is released from organic acids for use in the Calvin cycle.
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Term: crassulacean acid metabolism (CAM)
Definition: An active transport protein in a cell membrane that uses ATP to transport hydrogen ions out of a cell against their concentration gradient, generating a membrane potential in the process.
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Term: proton pump
Definition: The meshwork surrounding animal cells, consisting of glycoproteins, polysaccharides, and proteoglycans synthesized and secreted by cells.
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Term: extracellular matrix (ECM)
Term: bundle-sheath cell
Definition: In C4 plants, a type of photosynthetic cell arranged into tightly packed sheaths around the veins of a leaf.
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Biology: A Global Approach, Global Edition Vocab Self-Quiz
Definition: A light-capturing unit in a chloroplast’s thylakoid membrane or in the membrane of some prokaryotes; it has two molecules of P700 chlorophyll a at its reaction center.
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Term: photosystem I (PS I)
Definition: A protective layer external to the plasma membrane in the cells of plants, prokaryotes, fungi, and some protists. Polysaccharides such as cellulose (in plants and some protists), chitin (in fungi), and peptidoglycan (in bacteria) are important structural components of cell walls.
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Term: cell wall
Definition: A complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes.
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Term: ATP synthase
Definition: An organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present.
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Term: facultative anaerobe
Definition: An assemblage of microtubules and associated proteins that is involved in the movement of chromosomes during mitosis.
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Term: mitotic spindle
Definition: A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate.
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Term: C3 plant
Definition: A metabolic pathway that consumes oxygen and ATP, releases carbon dioxide, and decreases photosynthetic output. Photorespiration generally occurs on hot, dry, bright days, when stomata close and the O2/CO2 ratio in the leaf increases, favoring the binding of O2 rather than CO2 by rubisco.
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Term: photorespiration
Definition: A protein that interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell.
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Term: motor protein
Definition: The difference in electrical charge (voltage) across a cell’s plasma membrane due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.
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Term: membrane potential
Definition: A complex of proteins associated with pigment molecules (including chlorophyll a, chlorophyll b, and carotenoids) that captures light energy and transfers it to reaction-center pigments in a photosystem.
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Term: light-harvesting complex
Definition: A glycoprotein in the extracellular matrix of animal cells that forms strong fibers, found extensively in connective tissue and bone; the most abundant protein in the animal kingdom.
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Term: collagen
Definition: A type of motor protein that associates into filaments that interact with actin filaments to cause cell contraction.
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Term: myosin
Definition: The second stage of mitosis, in which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the chromosomes.
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Term: prometaphase
Definition: A transport protein in the plasma membrane of animal cells that actively transports sodium out of the cell and potassium into the cell.
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Term: sodium-potassium pump
Definition: A transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and with hydrophilic regions in contact with the aqueous solution on one or both sides of the membrane (or lining the channel in the case of a channel protein).
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Term: integral protein
