Studied by 6 peopleMetabolism
All of the chemical reactions that occur within an organism
reactants
substance that goes into a chemical reaction
products
substances that are released by a chemical reaction.
metabolic pathways
series of chemical reactions that either build up or break down complex molecules
anabolic pathways
metabolic pathways that consumes energy to build a complex molecule from simpler compounds.
energy
the ability to do work
kinetic energy
the energy an object has due to its motion
thermal energy
energy associated with the movement of atoms or molecules
potential energy
stored energy (due to location or structure)
Chemical energy
A form of potential energy that is stored in chemical bonds between atoms (available to be released in a chemical reaction)
thermodynamics
the study of energy transformations
1st law of thermodynamics
The principle of conservation of energy. Energy can be transferred and transformed, but it cannot be created or destroyed.
2nd law of thermodynamics
Every energy transfer or transformation increases the entropy of the universe.
free energy
used to determine the likelihood of reactions
exergonic reaction
A spontaneous chemical reaction in which there is a net release of free energy. (negative delta G)
endergonic reaction
A non-spontaneous chemical reaction in which free energy is absorbed from the surroundings. (delta G is positive)
energy coupling
The use of an exergonic process to drive an endergonic one.
examples of mechanical work
beating of cilia, contraction of muscle cells, movement of chromosomes during cellular reproduction
examples of transport work
-pumping substances across membranes against the direction of spontaneous movement -moving vesicles from ER to Golgi
examples of chemical work
synthesis of complex molecules
ATP (adenosine triphosphate)
main energy source that cells use for most of their work
phosphorlyation
the addition of a phosphate group to a molecule, giving it energy
enzyme
type of protein that catalyzes (speeds up) reactions by lowering the activation energy
activation energy
energy that is needed to get a reaction started
substrate
A specific reactant acted upon by an enzyme
active site
region on an enzyme where the substrate binds
induced fit
The change in shape of the active site of an enzyme so that it binds more snugly to the substrate
Enzyme efficiency is affected by...
temperature, pH, chemicals, and environmental factors (i.e. salinity)
co-factors
non-proteins factors that help the enzyme function properly
holoenzyme
enzyme with its cofactor
Co-enzyme
An organic molecule serving as a cofactor (i.e. vitamins)
enzyme inhibitors
A chemical that interferes with and reduces an enzyme's activity
permanent enzyme inhibitor
inhibitor binds with covalent bonds (ex: toxins/poisons)
reversible enzyme inhibitors
bind to enzymes by weak interactions, usually competitive inhibitors
competitive inhibitors
bind to the active site of an enzyme, competing with the substrate
noncompetitive inhibitor
A substance that reduces the activity of an enzyme by binding to a location remote from the active site (the allosteric site), changing its shape so that it no longer binds to the substrate.
allosteric regulation
when molecules bind to an allosteric site which changes the shape and function of the active site can either lead to activation or inhibition
allosteric activation
substrate binds to allosteric site and stabilizes the shape of the enzyme so that the active sites remain open, increasing their activity
allosteric inhibition
substrate binds to allosteric site and stabilizes the enzyme shape so that the active sites are closed (inactive form)
cooperativity
substrate binds to one active site (on an enzyme with more than one active site) which stabilizes the active form
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.
catabolic pathways
metabolic pathways that release energy by breaking down complex molecules into simpler compounds
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