Chapter 6 Test Flashcards
The ability to do work (move matter)
Energy
Stored energy available to do work
Potential energy
Energy of motion
Kinetic energy
Amount of energy required to raise one gram of water one degree Celsius
(14.5—15.5)
calorie
The amount of energy required to raise one kilogram of water one degree Celsius
Calorie
Energy cannot be created nor destroyed, but can be converted to other forms
First Law of Thermodynamics; Law of the Conservation of Energy
When energy is transformed from one form to another, some energy is lost in the form of heat
Second Law of Thermodynamics; Law of Entropy
Tendency toward disorder; all energy transformations head towards disorder
Entropy
The universe’s entropy is always _______
Increasing
The sum of all chemical reactions in a cell
Metabolism
All reactions that are making molecules
Anabolism
All reactions that are breaking things down
Catabolism
When bonds are made, energy is stored. When bonds are broken, energy is released
Reactions
Require input of energy; molecules are being built; product contains more energy than reactants
Endergonic reaction
Molecules are broken down and energy is released
Exergonic reactions
Unit of energy in the cell; required for metabolic functions
ATP
Bond between second and third phosphates in ATP contains just the right amount of ______ to fuel most metabolic reactions
Energy
One reaction often drives another reaction
Coupled reaction
Adding a phosphate to any molecule
Phosphorylation
ATP functions
Chemical work
Transport work
Mechanical work
ATP function that builds
Chemical work
ATP function that deals with moving within the cell, movement of the cell itself, or moving things across the plasma membrane
Transport work
ATP function that deals with the movement of muscles
Mechanical work
catalysts that speed up chemical reactions; usually proteins, do not get permanently changed during the reactions, and they are very specific in what they do
Enzymes
Takes hydrogen off
Dehydrogenase
Step-wise sequences
Metabolic pathways
Substance that is being acted upon
Substrate
End molecule (what is produced)
Product
Molecules that come in between the process of the reaction
Intermediates
Types of metabolic pathways
Straight
Branch
Cycle
Describe enzymes
Catalysts that speed up chemical reactions
Usually proteins
Do not get permanently changed during the reaction
Very specific in what they do
Recycled over and over
Usually end in the suffix “ase”
Usually tells within the word what it does or what it acts on
A + B > C > D > E
Straight chain
D >
A + B > C >
E >
Branch chain
A
E^
B
^
DCycles
Name for the temporary molecule where the enzyme and substrate are bound together
Enzyme-substrate complex
Place on the enzyme where the substrate binds with the enzyme
Active site
Theory of how enzyme-substrates work
Induced-fit model
Induced-fit model
Substrate binds to the active site
Enzyme changes shape
Shape change makes it easier for the reaction to proceed
Reaction is finished so the enzyme releases its products and returns to its original shape
Active site is available for more substrate
Step in the induced-fit model that is the induced fit
Enzyme changes shape
Energy needed for a reaction to occur
Energy of activation
______ lower the energy of activation
Enzymes
Effect the speed of an enzymatic reaction
Factors
Factors of an enzymatic reaction
Substrate concentration Enzyme concentration Optimal pH Temperature Cofactors and coenzymes Denaturation
The higher the ______ concentration, the more the reaction will occur. The more ______ concentration you have, the better the reaction will be
Substrate; enzyme
Human blood is 7.35-7.45
Optimal pH
Reactions occur best at the regular body ______ of that organism
Temperature
Their presence affects the speed of the reaction
Cofactors and coenzymes
Inorganic ion needed for the active site of an enzyme to work properly
Cofactor
Nonprotein organic molecule needed at the active site for the enzyme to work properly; often require vitamins to work
Coenzyme
Change in the shape of an enzyme where that it no longer functions properly; caused by changes in the pH and temperature (reversible or irreversible)
Denaturation
All enzymes are dependent upon their _____ to work properly
Shape
Types of enzyme inhibition
Competitive
Noncompetitive
Both the substrate and inhibitor can fit in the active site, but whichever one gets there first gets to stay
Competitive inhibition
Inhibitor binds to the allosteric site which causes a shape change in the active site which inhibits the substrate from fitting
Noncompetitive inhibition
Site other than the active site where the inhibitor bonds
Allosteric site
When one of the products in a pathway inhibits a previous reaction in the pathway
Negative feedback
One of the products in a pathway makes reactions go faster
Positive feedback
Loss or gain of electrons; almost always coupled
Oxidation-reduction reactions
Loss of electron (hydrogen ion)
Oxidation
Gain of electron (hydrogen ion)
Reduction
The type of molecule an enzyme is is a ______
Protein
