Studied by 16 people
Metabolic Pathway
begins with a specific molecule and ends with a product Each step is catalyzed by a specific enzyme
Anabolic pathway
consumes energy to build complex molecules from simpler ones Nonspontaneous +ΔG Endergonic reaction
Endergonic reaction
Absorbs free energy from its surroundings Nonspontaneous +ΔG
Catabolic pathway
Released energy by breaking down complex molecules into simpler compounds Spontaneous -ΔG Exergonic reaction
Exergonic reaction
Proceeds with a net release of energy Spontaneous -ΔG
Spontaneous reaction
Proceeds without an input of energy
ΔG
change in free energy
Free energy
The measure of the capacity of the system to do work
equilibrium
A state in which relations in an isolated system do not have to do work
Energy coupling
The use of an exergonic process to drive an endergonic one
second law of thermodynamics
Every energy transfer or transformation increases the entropy of the universe
Entropy
A measure of disorder
First Law of Thermodynamics
Energy can be transferred or transformed but it cannot be created or destroyed
Open system
Energy and matter can be transferred between the system and its surroundings
Energy
The capacity to cause change
Kinetic energy
Energy in motion
Thermal energy
Kinetic energy associated with random movement of atoms or molecules
heat
Thermal energy from one object to another
Potential energy
Energy that matter possesses because of its location or structure
Chemical energy
Potential energy available for release in a chemical reaction
Bioenergetics
The study of how energy flows through living organisms
cell’s main kinds of work
chemical, transport, mechanical
ATP (adenosine triphosphate)
composed of ribose, adenine, and 3 phosphate groups drives energy coupling and helps make RNA
Phosphorylated
attaches a phosphate
ATP hydrolysis
powers transport and mechanical work in the cell Renewable- regenerated by the addition of a phosphate group to ADP
Kinase
Enzyme that attaches a phosphate group
phosphatase
Enzyme that removes a phosphate group
Enzyme/catalyst
increases the rate of a reaction without being consumed
Activation Energy
Initial energy needed to start a reaction
Substrate
The reactant an enzyme works on
Enzyme-substrate complex
The enzyme binding to its substrate
Active site
The region on the enzyme where the substrate binds
Induced fit
Of the enzyme to the substrate grunge chemical groups of the active site together
Effects of temperature and pH on enzymes
Excessive heat causes the atoms to vibrate and they hit each other and they lose their shape (denaturation by heat)
every enzyme has an optimum temperature and pH and if it strays away it will not work
Cofactors
Inorganic enzyme helpers
Coenzymes
Organic enzyme helpers
Competitive inhibitors
Binds to the active site if an enzyme, competing with the substrate
Noncompetitive inhibitors
Binds to another part of the enzyme, causing it to change shape and making the active site less effective
Allosteric regulation
Binds somewhere other than the active site Can inhibit or enhance enzyme activityCooperativity
Feedback inhibition
The end product of a metabolic pathway shuts down the pathway Prevents a cell from wasting resources by producing more of product than is needed
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