Energy, Catalysis, Biosynthesis Flashcards
ATP
Activated carrier that serves as the principal carrier of energy in cells; a nucleoside triphosphate composed of adenine, ribose, and three phosphate groups. (See Figure 2 - 26.)
Reduction
Addition of electrons to an atom, as occurs during the addition of hydrogen to a carbon atom or the removal of oxygen from it; can also refer to a partial shift of electrons between atoms linked by a covalent bond.
Acetyl CoA
Activated carrier that donates the carbon atoms in its readily transferable acetyl group to many metabolic reactions, including the citric acid cycle and fatty acid biosynthesis; the acetyl group is linked to coenzyme A (CoA) by a thioester bond that releases a large amount of energy when hydrolyzed.
Substrate
A molecule on which an enzyme acts to catalyze a chemical reaction.
NADH
Activated carrier of electrons that is widely used in the energy-producing breakdown of sugar molecules. (See Figure 3 - 34.)
Equilibrium
State in which the forward and reverse rates of a chemical reaction are equal so that no net chemical change occurs.
Standard free-energy change
DeltaG0 (The free-energy change measured at a defined concentration, temperature, and pressure. )(See also free-energy change.)
Enzyme
A protein that catalyzes a specific chemical reaction.
Cell respiration
Process by which cells harvest the energy stored in food molecules; usually accompanied by the uptake of O2 and the release of CO2.
Anabolism
Set of metabolic pathways by which large molecules are made from smaller ones.
Equilibrium constant
K (For a reversible chemical reaction, the ratio of substrate to product when the rates of the forward and reverse reactions are equal.)
Free-energy change
&Delta G (
Going from ADP to ATP is what?
Positive delta G
Photosynthesis is what type of process?
Reduction process where food molecules (sugar) is formed
Metabolism
The sum total of the chemical reactions that take place in the cells of a living organism.
NADPH
Activated carrier closely related to NADH and used as an electron donor in biosynthetic pathways. In the process it is oxidized to NADP+.
Oxidation
Removal of electrons from an atom, as occurs during the addition of oxygen to a carbon atom or when a hydrogen is removed from a carbon atom; can also refer to a partial shift of electrons between atoms linked by a covalent bond.
Free energy
G (Energy that can be harnessed to do work, such as driving a chemical reaction.)
Catalyst
Substance that accelerates a chemical reaction by lowering its activation energy; enzymes perform this role in cells.
NADP+
Molecule that accepts a hydride ion (H - ) from a donor molecule, thereby producing the activated carrier NADPH; widely used as an electron donor in biosynthetic pathways.
Catabolism
Set of enzyme-catalyzed reactions by which complex molecules are degraded to simpler ones with release of energy; intermediates in these reactions are sometimes called catabolites.
Photosynthesis
The process by which plants, algae, and some bacteria use the energy of sunlight to drive the synthesis of organic molecules from carbon dioxide and water.
Activated carrier
A small molecule that stores energy or chemical groups in a form that can be donated to many different metabolic reactions. Examples include ATP, acetyl CoA, and NADH.
Biosynthesis
An enzyme-catalyzed process by which complex molecules are formed from simpler substances by living cells; also called anabolism.
