Term
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Definition
| A flattened, membranous sac inside a chloroplast |
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Term
| Splitting of Carbon dioxide to form oxygen gas and carbon compounds occurs during |
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Definition
| neither photosynthesis nor respiration |
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Term
| Signal Transduction Pathway |
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Definition
| A series of steps linking a mechanical, chemical, or electrical stimulus to a specific cellular response. Example:Vision |
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Term
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Definition
A signaling molecule binds to a receptor protein causing it to change shape.
The binding between a signal molecule (ligand) and receptor is highly specific.
A shape change in the receptor is often the initial transduction of the signal.
Most signal receptors are plasma membrane proteins. |
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Term
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Definition
| A molecule that binds specifically to another molecule, usually a larger one. Doesn't necessarily go through a chemical reaction. |
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Term
| G Protein-coupled receptor (GPCR) |
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Definition
| A signal receptor protein in the plasma membrane that responds to the binding of a signaling molecule by activating a G protein. Also called a G protein-linked receptor. |
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Term
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Definition
| A GTP binding protein that relays signals from a plasma membrane signal receptor known as a G protein coupled receptor to other signal transduction proteins inside the cell. |
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Term
| Receptor Tryosine Kinases |
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Definition
| A receptor protein spanning the plasma membrane, the cytoplasmic (intracellular) part of which can catalyze the transfer of a of a phosphate group from ATP to a tyrosine on another protein. Receptor tyrosine kinases often respond to the binding of a signaling molecule by dimerizing and then phosphorylating a tyrosine on the cytoplasmic portion of the other receptor in the dimer. The phosphorylated tyrosines on the receptors then activate other signal transduction proteins within the cell. |
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Term
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Definition
A transmembrane protein containing a pore that opens or closes as it changes shape in response to a signaling molecule (ligand), allowing or blocking the flow of specific ions; also called an ionotropic receptor. |
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Term
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Definition
| Factors that control transcription |
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Term
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Definition
| Cellular uptake of biological molecules and participate matter via formation of vesicles from the plasma membrane. Can be mediated by receptors. |
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Term
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Definition
| An extracellular glycoprotein secreted by animal cells that helps them attach to the extracellular matrix. |
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Term
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Definition
| In animal cells, a transmembrane receptor protein with two subunits that interconnects the extracellular matrix and the cytoskeleton. |
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Term
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Definition
| A series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule to simpler molecules (catabolic pathways) |
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Term
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Definition
| An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein. |
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Term
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Definition
| An enzyme that removes phosphate group from (dephosphorylates) proteins, often functioning to reverse the effect of a protein kinase. |
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Term
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Definition
| A small, nonprotein, water soluble molecule or ion, such as calcium ion (Ca^2+) or cyclic AMP, that relays a signal to a cell's interior in response to a signaling molecule bound by a signal receptor protein. |
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Term
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Definition
Cyclic adenosine monophosphate, a ring-shaped molecule made from ATP that is a common intracellular signaling molecule (second messenger) in eukaryotic cells. It is also a regulator of some bacterial operons. |
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Term
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Definition
An enzyme that converts ATP to cyclic AMP in response to an extracellular signal. |
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Term
| Inositol Triphosphate (IP3) |
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Definition
A second messenger that functions as an intermediate between certain signaling molecules and a subsequent second messenger, Ca2+, by causing a rise in cytoplasmic Ca2+ concentration. |
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Term
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Definition
A second messenger produced by the cleavage of the phospholipid PIP2 in the plasma membrane. |
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Term
Signal transduction pathway |
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Definition
A series of steps linking a mechanical, chemical, or electrical stimulus to a specific cellular response. |
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Term
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Definition
| Cell signaling leads to regulation of transcription or cytoplasmic activities |
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Term
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Definition
A signaling molecule binds to a receptor protein, causing it to change shape |
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Term
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Definition
Cascades of molecular interactions relay signals from receptors to target molecules in the cell |
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Term
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Definition
A type of large relay protein to which several other relay proteins are simultaneously attached, increasing the efficiency of signal transduction. |
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Term
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Definition
A type of programmed cell death, which is brought about by activation of enzymes that break down many chemical components in the cell. Integrates multiple cell signaling pathways. |
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Term
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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. |
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Term
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Definition
| Fluid Mosaics of lipids and proteins |
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Term
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Definition
| Any of a group of large biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water. |
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Term
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Definition
| A lipid made up of glycerol joined to two fatty acids and a phosphate group. The hydrocarbon chains of the fatty acids act as nonpolar, hydrophobic tails, while the rest of the molecule acts as a polar, hydrophilic head. Phospholipids form bilayers that function as biological membranes. |
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Term
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Definition
| Having both a hydrophilic region and a hydrophobic region. |
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Term
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Definition
| The membrane at the boundary of every cell that acts as a selective barrier, regulating the cell's chemical composition. |
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Term
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Definition
| 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. |
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Term
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Definition
| A fatty acid that has one or more double bonds between carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton. |
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Term
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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
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Definition
| A protein loosely bound to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer. |
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Term
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Definition
| A property of biological membranes that allows them to regulate the passage of substances across them. |
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Term
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Definition
| A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane. |
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Term
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Definition
| A channel protein in the plasma membrane of a plant, animal, or microorganism cell that specifically facilitates osmosis, the diffusion of free water across the membrane. |
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Term
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Definition
| Transforms matter and energy, subject to the laws of thermodynamics |
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Term
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Definition
| The totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism. |
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Term
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Definition
| A series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule to simpler molecules (catabolic pathway). |
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Term
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Definition
| A metabolic pathway that releases energy by breaking down complex molecules to simpler molecules. |
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Term
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Definition
| A metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules |
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Term
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Definition
| The overall flow and transformation of energy in an organism. (2) The study of how energy flows through organisms. |
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Term
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Definition
| The capacity to cause change, especially to do work (to move matter against an opposing force). |
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Term
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Definition
| The energy associated with the relative motion of objects. Moving matter can perform work by imparting motion to other matter. |
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Term
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Definition
| A measure of the intensity of heat in degrees, reflecting the average kinetic energy of the molecules. |
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Term
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Definition
| The total amount of kinetic energy due to the random motion of atoms or molecules in a body of matter; also called thermal energy. Heat is energy in its most random form. |
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Term
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Definition
| The energy that matter possesses as a result of its location or spatial arrangement (structure). |
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Term
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Definition
| Energy available in molecules for release in a chemical reaction; a form of potential energy. |
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Term
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Definition
| The study of energy transformations that occur in a collection of matter. See first law of thermodynamics; second law of thermodynamics. |
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Term
| First Law of thermodynamics |
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Definition
| The principle of conservation of energy: Energy can be transferred and transformed, but it cannot be created or destroyed. |
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Term
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Definition
| A measure of disorder, or randomness. |
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Term
| Second Law of thermodynamics |
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Definition
| The principle stating that every energy transfer or transformation increases the entropy of the universe. Usable forms of energy are at least partly converted to heat. |
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Term
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Definition
| A process that occurs without an overall input of energy; a process that is energetically favorable. |
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Term
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Definition
| The portion of a biological system's energy that can perform work when temperature and pressure are uniform throughout the system. The change in free energy of a system (DG) is calculated by the equation DG = DH - TDS, where DH is the change in enthalpy (in biological systems, equivalent to total energy), T is the absolute temperature, and DS is the change in entropy. |
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Term
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Definition
| A spontaneous chemical reaction, in which there is a net release of free energy. |
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Term
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Definition
| A nonspontaneous chemical reaction, in which free energy is absorbed from the surroundings. |
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Term
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Definition
| A chemical agent that selectively increases the rate of a reaction without being consumed by the reaction. |
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Term
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Definition
| the physical process by which a polypeptide folds into its characteristic and functional three-dimensional structure from random coil. |
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Term
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Definition
| by coupling exergonic reactions to endergonic reactions |
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Term
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Definition
| In cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction. |
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Term
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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
| ATP (Adenosine Triphosphate) |
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Definition
| An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells. |
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Term
| Phosphorylated intermediate |
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Definition
| A molecule (often a reactant) with a phosphate group covalently bound to it, making it more reactive (less stable) than the unphosphorylated molecule |
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Term
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Definition
| no explosions, just changes in protein folding or “relaxation”. |
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Term
| Enzymes speed up metabolic reactions |
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Definition
| by lowering energy barriers |
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Term
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Definition
| A macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction. Most enzymes are proteins. |
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Term
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Definition
| The amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation. |
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Term
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Definition
| The reactant on which an enzyme works. |
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Term
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Definition
| A temporary complex formed when an enzyme binds to its substrate molecule(s). |
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Term
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Definition
| The specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs. |
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Term
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Definition
| Caused by entry of the substrate, the change in shape of the active site of an enzyme so that it binds more snugly to the substrate. |
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Term
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Definition
| Any nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely and reversibly, along with the substrate, during catalysis. |
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Term
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Definition
| An organic molecule serving as a cofactor. Most vitamins function as coenzymes in metabolic reactions. |
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Term
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Definition
| A substance that reduces the activity of an enzyme by entering the active site in place of the substrate, whose structure it mimics. |
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Term
| Noncompetitive Inhibitors |
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Definition
| A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing the enzyme's shape so that the active site no longer effectively catalyzes the conversion of substrate to product. |
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Term
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Definition
| The binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site. |
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Term
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Definition
| A kind of allosteric regulation whereby a shape change in one subunit of a protein caused by substrate binding is transmitted to all the other subunits, facilitating binding of additional substrate molecules to those subunits. |
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Term
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Definition
| A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway. |
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Term
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Definition
| The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP. |
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Term
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Definition
| A catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid. |
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Term
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Definition
| A catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid. |
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Term
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Definition
| A catabolic pathway for organic molecules, using oxygen (O2) as the final electron acceptor in an electron transport chain and ultimately producing ATP. This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms. |
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Term
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Definition
| The complete or partial loss of electrons from a substance involved in a redox reaction. |
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Term
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Definition
| The complete or partial addition of electrons to a substance involved in a redox reaction. |
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Term
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Definition
| The attraction of a given atom for the electrons of a covalent bond. |
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Term
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Definition
| A series of reactions that ultimately splits glucose into pyruvate. Glycolysis occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration. |
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Term
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Definition
| A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA (derived from pyruvate) to carbon dioxide; occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration. |
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Term
| Oxidative Phosphorylation |
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Definition
| The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration. |
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Term
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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. |
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Term
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Definition
| An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Under aerobic conditions, most ATP synthesis in cells occurs by chemiosmosis. |
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Term
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Definition
| The potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of hydrogen ions (H+) across a biological membrane during chemiosmosis. |
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Term
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Definition
| A metabolic sequence that breaks fatty acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA. |
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Term
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Definition
| The conversion of light energy to chemical energy that is stored in sugars or other organic compounds; occurs in plants, algae, and certain prokaryotes. Most photosynthesis takes place in leaves which is an organ of the plant. |
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Term
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Definition
| Leaf cells specialized for photosynthesis. In C3 and CAM plants, mesophyll cells are located between the upper and lower epidermis; in C4 plants, they are located between the bundle-sheath cells and the epidermis. |
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Term
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Definition
| A microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant. |
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Term
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Definition
| The dense 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. |
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Term
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Definition
| 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. |
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Term
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Definition
| A flattened, membranous sac inside a chloroplast. Thylakoids often exist in stacks called grana that are interconnected; their membranes contain molecular “machinery” used to convert light energy to chemical energy. |
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Term
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Definition
| The first of two major stages in photosynthesis (preceding the Calvin cycle). These reactions, which 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. |
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Term
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Definition
| The second of two major stages in photosynthesis (following the light reactions), involving fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrate. |
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Term
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Definition
| The process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated across the thylakoid membrane of the chloroplast or the membrane of certain prokaryotes during the light reactions of photosynthesis. |
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Term
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Definition
| Nicotinamide adenine dinucleotide phosphate, an electron acceptor that, as NADPH, temporarily stores energized electrons produced during the light reactions. |
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Term
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Definition
| The initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism (a plant, another photosynthetic organism, or a chemoautotrophic prokaryote). |
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Term
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Definition
| The distance between crests of waves, such as those of the electromagnetic spectrum. |
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Term
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Definition
| The entire spectrum of electromagnetic radiation, ranging in wavelength from less than a nanometer to more than a kilometer. |
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Term
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Definition
| That portion of the electromagnetic spectrum that can be detected as various colors by the human eye, ranging in wavelength from about 380 nm to about 750 nm. |
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Term
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Definition
| A quantum, or discrete quantity, of light energy that behaves as if it were a particle. |
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Term
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Definition
| An instrument that measures the proportions of light of different wavelengths absorbed and transmitted by a pigment solution. |
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Term
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Definition
| The range of a pigment's ability to absorb various wavelengths of light; also a graph of such a range. |
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Term
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Definition
| A graph that profiles the relative effectiveness of different wavelengths of radiation in driving a particular process. |
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Term
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Definition
A green pigment located in membranes within the chloroplasts of plants and algae and in the membranes of certain prokaryotes. Chlorophyll a participates directly in the light reactions, which convert solar energy to chemical energy.
chlorophyll a - A photosynthetic pigment that participates directly in the light reactions, which convert solar energy to chemical energy. chlorophyll b - An accessory photosynthetic pigment that transfers energy to chlorophyll a. |
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Term
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Definition
| 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. There are two types of photosystems, I and II; they absorb light best at different wavelengths. |
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Term
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Definition
| A complex of proteins associated with a special pair of chlorophyll a molecules and a primary electron acceptor. Located centrally in a photosystem, this complex triggers the light reactions of photosynthesis. Excited by light energy, the pair of chlorophylls donates an electron to the primary electron acceptor, which passes an electron to an electron transport chain. |
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Term
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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
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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
| Primary Electron Acceptor |
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Definition
| In the thylakoid membrane of a chloroplast or in the membrane of some prokaryotes, a specialized molecule that shares the reaction-center complex with a pair of chlorophyll a molecules and that accepts an electron from them. |
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Term
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Definition
| A route of electron flow during the light reactions of photosynthesis that involves only photosystem I and that produces ATP but not NADPH or O2. |
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Term
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Definition
| The initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism (a plant, another photosynthetic organism, or a chemoautotrophic prokaryote). |
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Term
| glyceraldehyde-3-phosphate (G3P) |
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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
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Definition
| Ribulose bisphosphate (RuBP) carboxylase, the enzyme that catalyzes the first step of the Calvin cycle (the addition of CO2 to RuBP). |
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Term
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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
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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
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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
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Definition
| In C4 plants, a type of photosynthetic cell arranged into tightly packed sheaths around the veins of a leaf. |
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Term
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Definition
| An enzyme that adds CO2 to phosphoenolpyruvate (PEP) to form oxaloacetate in mesophyll cells of C4 plants. It acts prior to photosynthesis. |
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Term
| crassulacean acid metabolism (CAM) |
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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
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Definition
| A plant that uses crassulacean acid metabolism, an adaptation for photosynthesis in arid conditions. In this process, carbon dioxide 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
| 2 Ways that cells communicate |
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Definition
1.Local Signaling
A.Paracrine signaling
B.Synaptic signaling
2.Long-distance signaling
A.Endocrine signaling |
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Term
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Definition
| A secreted molecule that influences cells near where it is secreted |
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Term
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Definition
| The cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane. |
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Term
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Definition
| In multicellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the body, changing the target cells' functioning. Hormones are thus important in long-distance signaling. |
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Term
| Signal Transduction Pathway |
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Definition
| A series of steps linking a mechanical, chemical, or electrical stimulus to a specific cellular response. |
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Term
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Definition
| A signaling molecule binds to a receptor protein, causing it to change shape |
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