Metabolism+&+Enzymes


 * __Metabolism & Enzymes__**

By Lena Southep


 * Chapter 6. Objectives: 1-12

Related Activities**
 * Lab 2


 * Vocabulary**


 * **Catabolic pathways**- A metabolic pathway that releases energy by breaking down complex molecules into simpler compounds
 * **Energy**- The capacity to do work by moving matter against an opposing force.
 * **Kinetic energy**- The energy of motion, which is directly related to the speed of that motion. Moving matter does work by transferring some of its kinetic energy to other matter.
 * **Potential energy**- The energy stored by matter as a result of its location or spatial arrangement.
 * **First law of thermodynamics**- The principle of conservation of energy. Energy can be transferred and transformed, but it cannot be created or destroyed.
 * **Second law of thermodynamics**- The principle whereby every energy transfer or transformation increases the entropy of the universe. Ordered forms of energy are at least partly converted to heat, and in spontaneous reactions, the free energy of the system also decreases.
 * **Entropy**- A quantitative measure of disorder or randomness, symbolized by S.
 * **Free energy**- A quantity of energy that interrelates entropy (S) and the system's total energy (H); symbolized by G. The change in free energy of a system is calculated by the equation G= H - T *delta* S, where T is absolute temperature.
 * **Exergonic reaction**- A spontaneous chemical reaction in which there is a net realse of free energy.
 * **Endergonic reaction**- A nonspontaneous chemical reaction in which free energy is absorbed from the surroundings
 * **Energy coupling**- The use of an exergonic process to drive an endergonic one. A molecule called ATP is responsible for mediating most energy coupling in cells.
 * **Phosphorylated intermediate**- Used with the help of specific enzymes, the cells are able to couple the energy of ATP hydrolysis directly to endergonic processes by transferring a phosphate group from ATP to some other molecule.
 * **Catalyst**- A chemical agent that changes the rate of a reaction without being consumed by the reaction.
 * **Activation energy**- Provided in the form of heat that the reactant molecules absorb from the surroundings.
 * **Active site**- The specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds.
 * **Induced fit**- The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate.
 * **Cofactors**- 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 with the substrate during catalysis
 * **Coenzyme**- An organic molecule serving as a cofactor. Most vitamins function as coenzymes in important metabolic reactions.
 * **Competitive inhibitors**- A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics.
 * **Noncompetitive inhibitors**- A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.
 * **Allosteric site-** - A specific receptor site on an enzyme molecule remote from the active site. Molecules bind to the allosteric site and change the shape of the active site, making it either more or less receptive to the substrate.
 * **Feedback inhibition-**- A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway
 * **Cooperativity**- An interaction of the constituent subunits of a protein causing a conformational change in one subunit to be transmitted to all the others.

Induced Fit (above) For more information on enzymes, go here: http://staff.jccc.net/PDECELL/metabolism/enzymes/enzymes.html For problem sets, go here: http://www.biology.arizona.edu/biochemistry/problem_sets/metabolism/metabolism.html
 * Important Content**
 * Enzymes**
 * Enzymes are proteins
 * Chemical reactions are speeded up by something called a catalyst
 * Metabolism is a process for chemical reaction to occur
 * Metabolism**
 * Metabolism occurs in living cells
 * Divided into two groups: Catabolic reactions and Anabolic reactions
 * Catabolic reactions: The process of breaking down complex molecules into simpler compounds
 * Anabolic reactions: The process of building large molecules from small ones
 * Chemical reactions are organized into sequences
 * Transform food into energy for our bodies