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