Biology 1010 Chapter 8
mechanisms to lower activation energy
1. positioning substrates together in the proper orientation 2. applying torque on the substrates 3. providing the proper charge or pH microenvironment 4. adding or removing functional groups on the substrates
optimum temperature
35-40
optimum pH
6-8
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
noncompetitive inhibitor
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.
exergonic reaction
G is negative
Initial concentration of substrate affecting enzyme activity
The more substrate molecules that are available, the more frequently they access the active sites of the enzyme molecules
enzyme
a biological catalyst
cooperativity
a form of allosteric regulation that can amplify enzyme activity ex: binding of oxygen to hemoglobin
cofactor
a non-protein chemical compound that tightly and loosely binds with an enzyme or other protein ex: ionic metals = zinc
active site
a region on an enzyme that binds to a protein or other substance during a reaction.
coenzyme
a small organic molecule required to activate an enzyme ex: vitamin
substrate
a specific reactant acted upon by an enzyme
catalyst
a substance that speeds up the rate of a chemical reaction without being consumed in a chemical reaction
difference between allosteric activator and allosteric inhibitor
activator- bind to locations on an enzyme away from the active site inhibitor- modify the active site of the enzyme so that substrate binding is reduced or prevented
what is ATP made of?
adenine, ribose, 3 phosphate groups
ATP
adenosine triphosphate
Competive inhibitor
binds to active site and stops real substrate from binding (has a similar shape to the substrate for the active site noncompetitive does not)
noncompetitive and competitive inhibitor
both interfere with the functioning of the enzyme's active site and reducing the number of enzyme-substrate complexes to form
what are the 3 main kinds of work a cell does?
chemical, transport, mechanical
anabolic
consumes builds up ex: photosynthesis
free energy symbol
delta G
what human enzyme functions well in a pH of 2? where is it found?
digestive system in human stomach
photosynthesis is ...
endergonic, source energy is chemical energy (sunlight)
free energy
energy available to do work when temperature and pressure are uniformed throughout the system
activation energy
energy needed to start a reaction
pH affecting enzyme activity
enzymes with different pH are compartmentalized to different locations (optimum pH of 7.4 = the correct 3-D structure of the active site)
2nd law of thermodynamics
every energy transfer or transformation increases the entropy (disorder) of the universe.
cellular respiration is ...
exergonic, G is negative
temperature affecting enzyme activity
low temp doesn't provide enough energy and high temp result in the destruction/denaturation of enzymes, (enzymes are most active at 37 deg)
how does an enzyme catalyze a reaction?
lowers activation energy
open system
matter can enter from or escape to the surroundings ex: humans
explain how kinetic energy and heat are related
more kinetic = more heat
mechanical work
muscle contraction ex: beating of cilia
If energy is released, delta G must be what?
negative
two types of systems
open system and closed system
how is chemical energy a form of potential energy?
potential energy that can be released in a chemical reaction
catabolic
releases energy breaks down ex: cellular respiration
both catabolic and anabolic
requires enzymes to catalyze reactions
thermodynamics
study of energy transformation
allosteric regulation
the binding of a molecule to a protein that affects the function of the protein at a different site
chemical work
the making and breaking of chemical bonds ex: proteins
1st law of thermodynamics
the principle of conservation of energy. Energy can be transferred and transformed, but it cannot be created or destroyed.
transport work
the pumping of substances across membranes against the direction of spontaneous movement ex: ions
bioenergenetics
the study of how energy flows through living organisms
products
the substances that are formed by the chemical change
energy coupling
the use of an exergonic process to drive an endergonic one
metabolism
totality of an organism's chemical reaction
what does it mean for a molecule to be phosphorylated?
transfers a phosphate group
closed/isolated system
unable to exchange either energy or matter with its surroundings