Metabolism Flashcards
Metabolism
all chemical reactions in organisms; how organisms manage their energy resources
Bio energetics
study of metabolism
Metabolic pathway
a road map of chemical reactions that occur in a cell that begin with a specific molecule which is then altered in a series of defined steps which results in a certain product
Are the enzymes in the different steps of a metabolic pathway all the same
no there is a different enzyme for every step
Catabolic Pathways
break down/decompose by releasing energy
Anabolic Pathways
absorb enerhy and form stuff
example of catabolc pathway
cellular respiration
Why is cellular respiration a catabolic process
because the glucose is nroken down in the prescence of oxygen into carbon dioxide and water
Can metabolic pathways have only one product and starting molecule
no they can have more than one of both
Anabolic pathways aka
biosynthetic pathways
What is an example of an anabolic pathway
when amino acids form proteins
Bioenergetics
the study of how energy flows through living organisms
Energy
the capacity of something to cause change and re arrange matter
What are the different types of energy
kinetic energy and potential energy
Kinetic energy
the energy of motion
Potential energy
the energy that is stored in something
What is the amount of potential energy something has determined by
its position or structure
Where is the main source of energy found for living organisms
in between the second and third phosphate of ATP
What are the different types of kinetic energy
thermal energy and heat
Thermal energy
kinetic energy associated with the random movement of atoms or molecules
Heat
the transfer of thermal energy from one object to another
Chemical Energy
the potential energy available for release in a chemical equation
What are some examples of chemical energy
the energy that is relased when you digest food
When a woman climbs a ladder what type of energy is being lost and what type of energy is being gained
shes losing chemical energy bc shes using energy from the food that she ate and she is using it for kinetic energy to move up the ladder and she is gaining potential energy bc she is going up
Thermodynamics
the study of energy transformation that occur in a colection of matter
System
the matter under the study
Surroundings
everything outside the system
Isolated system
a system that is unable to change either its energy or matter with its surroundings outside the thermos
Open system
energy and matter can be transferred between the systems and its surroundings
What type of systems are organisms
open
1st law of thermodynamics
Conservation of Energy
Conservation of energy
the energy of the universe is constant: energy can be transferred and transformed but it cannot be created or destroyed
2nd Law of Thermodynamics
for energy transfer or transformation increases the entropy of the universe
When organisms do chemical reactions in their bodies and their is excess energy what does it come off as
heat
Entropy
a measure of disorder
Why do organisms give off heat, as usable energy, when they do chemical reactions in their body
to make the world more unstable
Spontaneous process
a reaction that leads to a rise in entropy on its own without the input of energy
Is something that is spontaneous favorable or not favorable
favorable
Nonspontaneous reaction
a reaction leads to a decrease in entropy
How does energy go into most ecosystems
as light
How does energy leave most ecosystems
heat
Can entropy ever decrease
entropy can decrease ( like for humans it can) and the universe will remain with increasing entropy bc humans are small so this is still true thermodynamically
Is the universe the system or the surroundings
both
Gibbs Free energy
the measure of a systems instability and the energy available to do work
Gibbs Free Energy symbol
ΔG
Gibbs free energy formula
ΔG = ΔH -TΔS
Entropy Symbol
ΔS
What must temperature be in when doing gibbs free energy calculations
kelvin
C –> K
c + 273.15
For what sign of ΔG is a reaction spontaneous
-
If ΔG is positive is the process spontaneous
no
If ΔG is 0 is the process spontaneous
no
Does a spontaneous process have more or less free energy
less
Is more or less enthalpy favorable for spontaneity
less
Equilibrium
maximum state of stability
Which variable has the least value in gibbs free energy when an equation is at equilibrium
G
When can something do work
when it is spontaneous and it moves towards equilibrium
Exergonic reaction
energy outward
Spontaneous = energetically bad or good
good
Do exergonic or endergonic reactions occur spontaneously
exergonic
Endergonic reaction
one that absorbs free energy from its surroundings
What is the sign of ΔG in endergonic reactions
+
Example of an endergonic reaction
photosynthesis
If reactions in a cloed system reach equilibrium what happens to work
you cant do ti
What kind of system are organisms
open multistep
Chemical Work
the pushing of endergonic reactions that would not occur spontaneously
Transport work
the pumping of substances across membranes against the direction of spontaneous movement
What is the value of ΔG at equilibrium
0
What are the different types of work in a cell
chemical
transport
mechanical
Energy coupling
the use of an exergonic process to drive an endergonic one
What type of reaction is going from ATP to ADP
exergonic
How do you go from ATP to ADP
hydrolyze the last phosphate group off of ATP
Why is the reaction of ATP –> ADP important
it releases alot of energy - more than otger molecules - because of the instability of the 3 phospate groups bc they all have a negative hcarge
Enzyme
protein that acts as a catalyst to speed up a reaction without being consumed or changed by the reaction
DEscribe energy in a chemical reaction
energy goes into the reactants and they are unstable
new bonds on the product molecules form and energy is released as heat so that the products have less energy than the reactants
Activation Energy
the energy needed to contort the reactant molecules so the bonds can break
Transition State
when the molecules have absorbed enough energy for the bonds to break and are unstable
What is needed to reach the transition state
heat –> thermla energy to give the atoms enegry so they can become unstable and break
How do enzymes help make reactions faster
they lower the activation energy which allows molecules to reach the transition state without absorbing too much thermal energy which would be harmful to organic molecules
Enzymes can catalyze any reaction true or false
false –> all things have specific enzymes
Substrate
the reactant an enzyme acts on
Enzyme-substrate complex
the thing formed when an enzyme fits into its active site and it alters the substrate slightly so that it bonds to it to hold it in place
Active Site
the restricted region of the enzyme molecule that binds to the substrate (enzyme is bigger)
Induced fit
the hold of the enzyme on the substrate tightens bc it brings chemical groups of the active site into positions that enhance their ability to catalyze the chemical reaction ALSO done with the help of cofactors or coenzymes
Phosphorylation
when you add a phosphate group to smth to hold energy
Rate of cayalyzation
1000/sec
Enzymes can catalyze both the forward and the reverse reaction true or false
true
How are most substrate held in place in the active site
with hydrogen and ionic bonds from the R-groups of the amino acids
How do you know which reaction an enzyme is going to catalyze (forward or reverse)
it will catalyze the one with the lower ΔG
What are the ways that an enzyme catalyzes a reaction
orientation
microenvironment
enzyme stretching
amino acid
Orientation catalyzation
enzyme puts substrates together perfecty (in the position that they connect bc they usually js bump around and leave it to chance)
Microenvironment catalyzation
the enzyme makes itself more optimal for a substrate to bind to compared to the surrounding conditions
Enzye stretchig catalyzation
the enzyme stresses and breaks its own chemical bonds to lower the activation energy –> the enzyme distorts itself so that the transition state is easier to reach
Amino Acid catalyzation
amino acids in the active site participate in the process by bonding etc
What factors affect how enzymes function
pH, temperature, and sometimes special chemicals
Temperature optimal of enzyme
not too hot bc even tho hot speeds the particles up so they reach the activation energy, it will denature the protein bc it will break the H and ionic bonds
What is the normal pH range for more enzymes
6-8
Cofactors
something thats not a protein that helps catalyze; lots of enzymes have them and sometimes theyre already on the active site and sometimes theyre not
Coenzyme
organic things that help catalyze like the cofactors
Examples of cofactors
any vitamin
Competitive inhibitors
molecules that reduce the productivity of enzymes by blocking the substrates from entering active sites (bind in the active site itself)
non-competitive inhibitors
mostl small molecules that do not compete directly with the substrate in the active site and innstead they bind ot the enzyme away from the active site to alter the shape of the enzyme so that even if the substrate can bind, the active site functions less effectively if at all
Enzyme inhibitors
inihibitor molecules that bind to an enzyme to turn it off –> the do this because theres stuff near the enzyme that shouldn’t be there or you don’t need soething (like bacteria or excess protein you dont want)
Allosteric Regulation
any case in which a proteins function at one site is affected by the binding of a refulatory molecule to a separate site -> can result in inhibition or stimulation
What is alloesteric regulation used ofr
for molecules that oscillate between active and inactive form to keep it one form
Alloesteric site aka
regulatory site
IS the alloesteric site the active site
no theyre near each other so that the regulatory site affects the active site but they are not the same
Cooperativity
a kind of allosteric activation where a substrate molecule binds to one active site in a multisububit enzyme that triggers a shape in all of the subunits (stops it from oscilatting) which allows substrates to bind to the other active sites
Feedback inhibition
when the product of a metabolic pathway binds to the primary enzyme used to make that pathway, aloesterically inhibiting it from creating more of the same protein
What is the usual source of energy for energy coupling in organisms
ATP
ATP
Adenosine triphosphate
Is the hydrolysis of ATP exergonic or endergonic
exergonic
When ATP is hydrolyzed how much energy is released
7.3kcal/mol
Phosphorylated Intermediate
the recipient molecule with the phosphate group covalently bonded to it is
How often does induced fit occur
ALL THE TIME NOT OPTIONAL
ΔG fomula (NOT THE ENTHALPY ONE)
ΔG = Gf - Gi
Why does a negative ΔG connotate that the reaction can occur
because that means that the final value of free energy is less than the inital value. this means that energy was released because there was energy that went in and you used it for work
Why does a positive ΔG connotate that the reaction can occur
this means no reaction happened because the energy wet up so nothing was used for work so you still need to get some energy to do a reaction
If the absolute value of ΔG is __the energy needed to hydrolyze ATP, the reaction can work
equal to or less than
