Chapter 8 Flashcards
What is metabolism? (2)
Totality of an organism’s chemical reaction
Emergent property of life
What is a metabolic pathway? (3)
Begins with a specific molecule
altered in a series of defined steps, with each step catalyzed by an enzyme
results in a certain product
What is a catabolic pathway, and an example? (
Processes that breakdown molecules to release energy
ex- Cellular respiration
What is an anabolic pathway, and an example?
consumes energy to build complicated molecules
ex- photosynthesis
What is bioenergetics?
study of how energy flows through living organisms
What is energy?
Capacity to cause change.
What is kinetic energy?
Relative motion of objects
What is thermal energy?
Kinetic energy associated with the random movement of atoms or molecules
What is heat?
transfer of thermal heat
What is potential energy?
energy matter possesses because of its location or structure
What is chemical energy?
potential energy available for release in a chemical reaction
What is thermodynamics?
Study of energy transformations that occur in a collection of matter
What is an isolated system?
a system unable to exchange either energy or matter with its surroundings
What is an open system and an example?
a system able to exchange energy and matter with its surroundings
ex- organisms
What is the first law of thermodynamics?
energy can be transferred or transformed, but it cannot be created or destroyed
What is the second law of thermodynamics?
every energy transfer or transformation increases the entropy of the universe
What is entropy?
Measure of disorder
What is a spontaneous process (2)
if a given process leads to an increase in entropy, the process proceeds without requiring an input of energy
energetically favorable
What is free energy?
portion of a system’s energy that can perform work when temp and pressure are uniform throughout the system
What does the sign of free energy mean?
Negative free energy indicates a spontaneous reaction
How do free energy and a spontaneous reaction correlate?
Every spontaneous reaction decreases the system’s free energy
What does an increase in free energy mean? (2)
less stable
Greater work capacity
How does equilibrium affect free energy?
A process is spontaneous and can perform work only when it is moving toward equilibrium
What is an exergonic reaction and an example? (3)
Releases energy
spontaneous
ex- loss of energy due to breaking down of molecules
What is an endergonic reaction? (2)
Absorbs free energy from its surroundings
nonspontaneous
What is chemical work in the body?
Pushing of endergonic reaction
What is transport work in the body?
pumping of substances across membranes against the direction of spontaneous movement
what is mechanical work in the body?
- beating of celia, contraction of muscles
What is energy coupling and an example?
use of an exergonic process to drive an endergonic one
ex- ATP used in reactions
What is adenosine triphosphate made up of, and how does it work?
contains one sugar ribose, adenine, and three phosphate groups
Works by breaking the phosphate group by hydrolysis, turning into ADP
What is a phosphorylated intermediate?
recipient molecule with the phosphate group from a hydrolyzed ATP
what is activation energy?
Initial energy required for starting a reaction
What is a transition state?
when molecules have absorbed enough energy for bonds to break, causing reactants to be in an unstable condition
Why can’t heat be the source of activation energy in cells? (2)
Heat will denature proteins and kill cells
It will speed up all reactions, not just those that are needed
What is a substrate?
The reactant an enzyme acts on
What is an active site?
region of an enzyme where it binds to a substrate
What is an induced fit?
when an enzyme slightly changes shape due to interactions between the substrate and the active site, binding them tighter
What is a cofactor?
Nonprotein molecules that help enzymes catalyze
What is a coenzyme?
Organic cofactors
What is a competitive inhibitor and how is it overcome?
reduce the productivity of enzymes by blocking substrates from entering active sites
Overcome by increasing concentration of substrate
what is a noncompetitive inhibitor?
binds to a an enzyme away from the active sit to alter the shape of the enzyme
What is an allosteric regulation?
when a protein’s function at one site is affected by the binding of a regulatory molecule to a separate site
what is cooperativity?
when a substrate binds to one active site of a multisubunit enzyme to trigger a shape change to increase catalytic activity
What is feedback inhibition?
a metabolic pathway is halted by the inhibitory binding of its end product to an enzyme that act early in a pathway
