Chapter 8 - An Introduction to Metabolism Flashcards
what are catabolic pathways
RELEASE energy by BREAKING DOWN complex
cellular respiration is…
catabolic(breakdown of glucose in the presence of O2)
what are anabolic pathways
CONSUME energy to BUILD complex molecules
potential energy is…
energy that is stored in the matter, depending on the location/structure (height)
chemical energy is…
potential energy available for release in a chemical reaction
what is thermodynamics
the study of energy transformations in a collection of matter
in an open system…
such as organisms, energy and matter can be transferred between the system and its surroundings
the first law of thermodynamics->
energy cannot be created or destroyed (energy of universe is constant)
the second law of thermodynamics->
every energy transfer increases the entropy of the universe(molecular randomness)
what is free energy
portion of system’s energy that can do work in a stable system, like a living cell
free-energy change of a reaction tells us…
whether or not the reaction is spontaneous
The free energy equation is…
ΔG = ΔH – TΔS
if ΔG is negative, then the process is
spontaneous
exergonic reactions:
energy released, which means it’s spontaneous
a cell does three main kinds of work:
chemical(push endergonic reactions), transport(pump substances across membranes against), and mechanical work (beat)
energy coupling is
the use of an exergonic process to drive an endergonic one
most energy coupling in cells is…
ATP coupling
ATP is composed of
triphosphate group + ribose (sugar) + adenine (nitrogenous base)
energy is released from ATP when
broken by hydrolysis (addition of water molecule)
ATP is regenerated in a cycle
phosphate group + ADP(di) creates ATP again, comes from catabolism (breakdown)
a catalyst is
chemical agent that speeds up a reaction
an enzyme is
a macromolecule that acts as a catalyst to speed up a reaction
process of enzymes
substrates can be manipulated in a variety of ways->active site is used->substrates are manipulated into products-> ejected out of enzyme site
cofactors are…
non protein helpers that bind to the enzyme permanently
inorganic cofactors->
include metal atoms
organic cofactors->
coenzymes, vitamins
what are competitive inhibitors…
closely resembling the substrate, can bind to the enzyme’s active site
the competitive inhibitor…
hinders production, blocks the way for substrates to get into the active site; increasing substrate concentration overcomes this
noncompetitive inhibitors are…
they bind to another part of the enzyme, changing the shape and making the active site less effective at catalyzing
in feedback inhibition…
the end product of the metabolic pathway shuts it down + prevents waste of chemical resources from more product than needed
ΔG is
free energy of the system
ΔH is
change in enthalpy (total energy)
TΔS
temperature(K) * change in entropy
