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Unit 2
AP Biology Unit 2 Vocabulary - Maldonado
| Term | Definition |
|---|---|
| Chloroplast | An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water |
| Endoplasmic Reticulum | An extensive membranous network in eukaryotic cells, continous with the outer nucleus membrane and composed of ribosome-free regions |
| Golgi Complex | An organelle in eukaryotic cells consisting of stack of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum and synthesize some products |
| Lysosome | A membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some products |
| Membrane-bound | Organelles surrounded by a phospholipid bilayer; it allows the organelles within the cells control what enters and leaves it by using a selectively permeable membrane |
| Mitochondrion | An organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP |
| Organelles | Any of several membrane-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells |
| Ribosome | A complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm; consists of a large and a small subunit |
| Vacuole | A membrane-bounded vesicle whose specialized function varies in different kinds of cells |
| Adenosine tryphosphate | A adenine-containing nucleoside tiphosphate that releases free energy when its phosphate bonds are hydrolyzed; the energy is used to drive endergonic reactions in cells |
| Apoptosis | A type of programmed cell death, which is brought about by activation of enzymes that break down many chemical components in the cell |
| ATP synthesis | A complex of several membranes that functions in chemiosmosis with adjacent electron transport chains; found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membrane of prokaryotes |
| Carbon Fixation Cycle/Calvin Benson Cycle | The second of two major stages in photosynthetic involving fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrates |
| Chlorophyll | A green pigment located in membranes within the chloroplasts of plants and algae and in the membranes of certain prokaryotes; its "a" version participates directly in the light reactions, which convert solar energy to chemical energy |
| Citric Acid Cycle/Krebs Cycle | A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA to carbon dioxide; occurs within the mitochondria in eukaryotic cell; second stage in cellular respiration |
| Electron Transport Chain | A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP |
| Grana | A stack of membrane-bounded thylakoids in the chloroplast; its function is in the light reactions of photosynthesis |
| Intracellular transport | The movement of vesicles and substances within the cell; required for maintaining homeostasis within the cell by responding to the physiological signals |
| Light dependent reactions | Reactions that occur on the thylakoid membranes of the chloroplast or on membranes of certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process |
| Photosynthesis | The conversion of light energy to chemical energy that is stored in sugars or other organic compounds; occurs in plants, algae, and certain prokaryotes |
| Photosystems | A light-capturing unit located in the thylakoid membrane of the chloroplast or in the mebrane of some prokaryotes, consisting of a reaction-center complex surrounded by numerous light-harvesting complexes |
| Stroma | The defense fluid within the chloroplast surrounding the thylakoid membrane and containing ribosomes and DNA; involved in the synthesis of organic molecules from carbon dioxide and water |
| Thylakoid | A flattened, membranous sac inside a chloroplast; often exist in stacks called grana that are interconnected; their membranes contain molecular "machinery" used to convert light energy to chemical energy |
| Turgor Pressure | The force directed against a plant cell wall after the influx of water and swelling of the cell due to osmosis |
| Membrane Exchange | It is a semi-permeable membrane that transports things through the membrane while blocking others |
| Plasma Membrane | The membrane at the boundary of every cell that acts as a selective barrier, regulating the cell's chemical composition |
| Surface Area to Volume Ratio | The ratio of a cell that is 6:1 ; a smaller object has greater ratio of surface area to volume |
| Aqueous | A solution in which water is the solvent |
| Fluid Mosaic Model | The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids |
| Glycolipid | A lipid with one or more covalently attached carbohydrates |
| Glycoprotein | A protein with one or more covalently attached carbohydrates |
| Steroid | A type of lipid characterized by a carbon skeleton consisting of four fused rings with various chemical groups attached |
| Cell Wall | A protective layer external to the plasma membrane in the cells of plants, prokaryotes, fungi, and some protists; cellulose is an important structural component for plants |
| Channel Protein | A type of transport protein that acts like a pore in the membrane that lets water molecules or small ions through quickly |
| Selective Permeability | A property of biological membranes that allows them to regulate the passage of substances across them |
| Transport Protein | A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane |
| Active Transport | The movement of a substance across a cell membrane against its concentration or electrochemical gradient, mediated by specific transport proteins and requiring an expenditure of energy |
| Concentration Gradient | A region along which the density of a chemical substance increases or decreases |
| Endocytosis | Cellular uptake of biological molecules and particulate matter via formation of vesicles from the plasma membrane |
| Exocytosis | The cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane |
| Passive Transport | The diffusion of a substance across a biological membrane with no expenditure of energy |
| Vesicle | A membranous sac in the cytoplasm of a eukaryotic cell |
| ATP synthase enzyme | A mitochondrial enzyme localized in the inner membrane, where it catalyzes the synthesis of ATP from ADP and phosphate |
| Facilitated Diffusion | The passage of molecules or ions down their electrochemical gradient across a biological membrane with the assistance of specific transmembrane transport proteins, requiring no energy expenditure |
| Ion | An atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge |
| Polarization | It is the existence of opposite electrical charges on either side of a cell membrane; difference in inside a cell versus the outside of a cell |
| ATPase enzyme | A group of enzymes that catalyze the hydrolysis of a phosphate bond in adenosine triphosphate; they harness the energy released from the breakdown of the phosphate bond and utilize it to perform other cellular reactions |
| Homeostasis | The steady-state physiological condition of the body |
| Hypertonic | Referring to a solution that, when surrounding a cell, will cause the cell to lose water |
| Hypotonic | Referring to a solution that, when surrounding a cell, will cause the cell to take up water |
| Isotonic | Referring to a solution that, when surrounding a cell, causes no net movement of water into or out of the cell |
| Osmoregulation | Regulation of solute concentrations and water balance by a cell or organism |
| Osmosis | The diffusion of free water across a selectively permeable membrane |
| Solute | A substance that dissolved in a solution |
| Solvent | The dissolving agent of a solution; water is the most versatile solvent known |
| Tonicity | The ability of a solution surrounding a cell to cause that cell to gain or lose water |
| Water Potential | The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure |
| Compartmentalization | Refers to the way organelles in eukaryotic cells live and work in separate areas within the cell in order to perform specific functions more efficiently |
| Eukaryotic | A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles |
| Intracellular | Located or occurring within a cell or cells |
| Endosymbiotic Theory | The theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell; the ehgulfed cell and the host cell evolved into a single organism |
| Prokaryotic | A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles |