Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chapter 8 introduction to metabolism - Coggle Diagram
Chapter 8 introduction to metabolism
Metabolism
The totality of an organism’s chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism.
metabolic pathways
A series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule to simpler molecules (catabolic pathway)
catabolic pathways
A metabolic pathway that releases energy by breaking down complex molecules to simpler molecules.
anabolic pathways
A metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules.
bioenergetics
1) The overall flow and transformation of energy in an organism. (2) The study of how energy flows through organisms.
types of energys
kinetic energy
1) The overall flow and transformation of energy in an organism. (2) The study of how energy flows through organisms.
A pool player uses the motion of the cue stick to push the cue ball, which in turn moves the other balls; water gushing through a dam turns turbines; and the contraction of leg muscles pushes bicycle pedals.
thermal energy
kinetic energy associated with the random movement of atoms or molecules; thermal energy in transfer from one object to another is called heat
potential energy
An object not presently moving may still possess energy. Energy that is not kinetic
chemical energy
Energy available in molecules for release in a chemical reaction; a form of potential energy.
laws of thermodynamics
first law
Energy can be transferred and transformed, but it cannot be created or destroyed
second law
It turns out that during every energy transfer or transformation, some energy is converted to thermal energy and released as heat, becoming unavailable to do work
spontaneous process
A process that occurs without an overall input of energy; a process that is energetically favorable
The free-energy change of a reaction tells us whether or not the reaction occurs spontaneously
free energy
is the portion of a system’s energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cel
energy coupling
the use of energy released from an exergonic reaction to drive an endergonic reaction.
exergonic reaction
A spontaneous chemical reaction in which there is a net release of free energy.
endergonic reaction
A nonspontaneous chemical reaction in which free energy is absorbed from the surroundings.
catalysis
A process by which a chemical agent called a catalyst selectively increases the rate of a reaction without being consumed by the reaction.
substrate
The reactant on which an enzyme works.
enzyme-substrate complex
A temporary complex formed when an enzyme binds to its substrate molecule(s).
active site
The specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs.
chemical work
the pushing of endergonic reactions that would not occur spontaneously, such as the synthesis of polymers from monomers
transport work
the pumping of substances across membranes against the direction of spontaneous movement
mechanical work
the contraction of muscle cells, and the movement of chromosomes during cellular reproduction
ATP
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
activation energy
The amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation.
Activation energy is often supplied by heat in the form of thermal energy that the reactant molecules absorb from the surroundings
cofactors
may be bound tightly to the enzyme as permanent residents, or they may bind loosely and reversibly along with the substrate
The cofactors of some enzymes are inorganic, such as the metal atoms zinc, iron, and copper in ionic form. If the cofactor is an organic molecule, it is referred to, more specifically, as a coenzyme
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
do not directly compete with the substrate to bind to the enzyme at the active site
feedback inhibition
the end product of a metabolic pathway allosterically inhibits the enzyme for a previous step in the pathway.
many enzymes are subject to allosteric regulation