Biochemistry Basics Flashcards
This is the transfer and use of energy in biologic systems.
Bioenergentics
This term refers to a change in free energy.
ΔG
ΔG approaches zero as the reaction approaches what?
Equilibrium
This is a change in heat content of the reactants and products.
Enthalpy
This is a change in randomness/disorder of the reactants and products.
Entropy
When ΔG is ___ the reaction proceeds, is exergonic, and implies a net loss of energy
Negative
When ΔG is ___ the reaction does not proceed, is endergonic, and implies a net gain of energy.
Positive. Energy must be added to the system to make it proceed.
When ΔG is ___ reactants are at equilibrium.
Zero
The free energy changes (ΔG) are ____ in any sequence of consecutive reactions.
Additive
As long as the sum of ΔG’s of the individual reactions is ____, the pathway moves forward.
Negative
This is when two reactions are happening at the same time.
Coupled reaction. The net ΔG must be negative for the reaction to occur.
This common reaction is characterized by the adding/removing of a phosphate group.
Phosphorylation
During phosphorylation, these enzymes add phosphate groups.
Kinases
During phosphorylation, these enzymes remove phosphate groups.
Phosphatases
This common reaction is characterized by the rearranging of atoms.
Isomerization
During isomerization, this enzyme rearranges atoms.
Isomerases
This common reaction is characterized by shifting a group on a molecule.
Mutation
During mutation, this enzyme shifts a group onto a molecule.
Mutases
This common reaction is characterized by the building of something.
Synthesis
During synthesis, these enzymes are used to build structures.
Synthases or synthetases
This common reaction is characterized by the oxidizing or reducing of something.
Redox
During redox, what enzyme is typically used.
Dehydrogenases. They are named after what they oxidize
Enzymes allow reactions to happen at ____ energies.
Lower
This common molecule is a derivative of niacin (B vitamin) and both accepts and donates electrons.
NAD
This common molecule is a derivative of riboflavin (B vitamin) and both accepts and donates electrons.
FAD
This common molecule is a derivative of pantothenic acid (B vitamin), holds and transfers acetyl or acyl groups, and creates a “thioester bond”
Coenzyme A (not a true enzyme)
What is the role of NADH + H+ and FADH2?
All they do is accept and donate electrons
How much energy does the removal of a phosphate group from ATP generate?
7.3 kilocalories
The presence of AMP stimulates a powerful enzyme called what?
AMPkinase
What does AMPK stimulate?
GLUT4, glycogen breakdown, glycolysis, fat burning, and LPLm activation
What does AMPK inhibit?
Glycogen synthesis, TAG synthesis, cholesterol synthesis, and fatty acid synthesis
In general, what does a high energy charge tell a cell to do?
It tells it to build things (fat, glycogen, glucose, cholesterol, nucleotides)
In general, what does a low energy charge tell the cell to do?
Create ATP (glycolysis, fat oxidation, aminoacid oxidation, Kreb’s cycle)
When the bond between ATP’s phosphate groups is broken, relatively large amounts of free energy are released. How much free energy is released?
ΔG=-7.3kcal/mol
To recreate ATP we have to get energy from molecules that can release (greater or lesser) than 7.3 kilocalories.
Greater
During enzyme regulation, what occurs to the enzyme when there is excess product? By what mechanism does this occur?
The enzyme is inhibited when there is excess product through the mechanism of enzyme inhibition. When there is scarce product the enzyme is stimulated.
During enzyme regulation, what occurs to the enzyme when there is excess reactant? Scarce reactant? By what mechanism does this occur?
The enzyme is stimulated when there is excess reactant through the mechanism of mass action. When there is scarce reactant the enzyme is inhibited.
This hormone is secreted in response to high blood glucose. It lowers blood glucose to baseline values and increases glucose in fat and muscle cells.
Insulin
This hormone is secreted in response to low blood glucose and increases blood glucose levels. It causes the liver to release glucose from storage (glycogen) and to make glucose (gluconeogenesis).
Glucagon
These hormones are involved in the flight or flight response.
Epinephrine and norepinephrine
