Ch 8--The role of Energy & Enzymes in Reactions Flashcards
What is Metabolism?
totality of reactions in the body.
…. is the break down complex substances into simpler ones= releasing energy. ex: starch=glucose during cellular respiration
-releases ATP through the breakdown of carbs, proteins, and lipids
Catabolism
What is Anabolism?
it is building complex substances from simpler ones- ex: building proteins from amino acids inside cells after respiration
- needs ATP for detoxification & thermogenesis
Thermodynamics is the relationships between… and their transformations from…
all forms of energy…one form to another
Energies exist in various forms such as:
potential, kinetic, heat, and chemical
What is Potential energy?
is the one that a system possesses due to its position.
What is Kinetic energy?
is the one that a system possesses due to motion
-K.E. of atom/molecules
- is the result of the K.E. of atoms & molecules that causes them to move in random directions
Heat energy
…. is P.E. of electrons released during…. reactions
Chemical energy….chemical
The study of Thermodynamics is what?
energy can be transformed from one to another
-Principle of Conservation of Energy
-Energy can neither be created nor destroyed, only transferred or transformed
-the energy of the universe remains constant
First Law of Thermodynamics
The Second Law of Thermodynamics is what?
There is an increase in the entropy of the universe for every transformation or transfer of energy. It leads to the unavailability of a system’s energy to do work.
What is Entropy?
chaos of molecules
What is G?
Free energy
Free energy is energy of a system that is….
capable of doing work
What are the two equations to calculate change in free energy?
ΔG=ΔH-TΔS or ΔG=g2-G1
ΔH is what?
change in enthalpy (total energy)
ΔS is what?
Change in entropy (disorder)
T is what?
Temperature in Kelvin (unit)
G2 is free energy of products=
final energy of the system
G1 is free energy of reactants=
initial energy of the system
If G1 is greater than G2 meaning….
the system is unstable (negative), capable of doing work (more free energy)
ΔG is negative=… excess energy will be released in the surrounding-….
spontaneous in nature; happens without input energy…. exergonic reaction
If G2 exceeds G1….
The system is now stable (positive), work has been done- endergonic reaction= non-spontaneous
Energy as ATP
is an energy molecule capable of releasing energy stored within its bonds, to carry out anabolic reactions {endergonic}
What is Endergonic Reactions?
they harness that energy from the breakdown of ATP
After hydrolysis ATP breaks down into what and it releases what?
ADP + Pi… it releases the potential energy stored in its bond to carry out Anabolic reactions in the cell
What fuels the reaction to combine ADP & Pi to make ATP?
Catabolism
What are Enzymes?
Proteins that act as catalyst & speed up chemical reactions
How do enzymes speed up chemical reactions?
by lowering the activation energy barrier
What is Activation Energy?
energy required by both spontaneous + non-spontaneous reactions in order to proceed & overcome the energy barrier
What is the activation energy barrier?
its the impediment the reactants need to overcome to become products.
How many times can an Enzyme lower the Ea Barrier?
4 ways
- An enzyme would orient the substrates correctly while….
binding them to their active sites
- An enzyme would…so they could be broken down faster into products
strain the bonds within substrates
- an enzyme would covalently bind to…. for a quick disintegration of substrate within itself.
the substrate and strengthen it s hold on it
- An enzyme is also capable of… to the substrates for efficient conversion into products
providing a micro favorable environment
What are effects that enzyme activity cause?
- general environmental factors, temp. & pH
- chemicals such as cofactors + inhibitors
What are cofactors and what are the two types?
they are enzyme helpers & may be inorganic or organic.
What is an inorganic cofactor?
they are metals in ionic form
What is an organic cofactor?
they are those that have carbon in their structure (these are coenzymes)
Competitive Inhibitors are what?
they COMPETE with the substrate for the active site & if successful they bind to the active site of an enzyme & thereby blocking substrate from binding there
Non-competitive Inhibitors are what?
DO NOT COMPETE for the active site but instead bind to another part of an enzyme resulting in the distortion of the active site & hence making it ineffective
A cell’s metabolic pathway is tightly regulated to prevent both shortage & surplus of products by keeping reactions in check is?
Allosteric Regulation
Allosteric Regulation may either stimulate or inhibit what?
an enzyme’s activity, depending on whether the substance bound to the enzyme is an active or an inhibitor
The process by which the end product of a metabolic pathway acts as an inhibitor for an enzyme to shut down that same pathway, so no more end product is made is….
Feedback Inhibition
Feedback Inhibition prevents…
wasting resources
Negative feedback loop is….
a product should not be synthesized any longer when it is beyond the required amount
