Biochem Exam 2

help.

the study of enzyme reaction rates

what is the definition of enzyme kinetics?

it increases linearly

What happens to the rate of enzyme activity when the concentration of enzyme increases?

it increases in a rectangular hyperbola

What happens to the rate of enzyme activity when the concentration of substrate increases?

it increases until optimal temperature is reached, then decreases as it becomes dangerous for the enzyme

What happens to the rate of enzyme activity when the temperature increases?

it increases until optimal pH is reached, then decreases as it becomes dangerous for the enzyme

What happens to the rate of enzyme activity when the pH increases?

rate constant (k)

what other constant is the proportionality constant equal to in enzyme kinetics?

Unimolecular and Bimolecular; 1/s and 1/(M*s)

what are the two reaction orders we need to know? What are their units?

it describes how the rate depends on the concentration (number of molecules that must collide to generate the product)

what is reaction order?

linear

What does the graph of a unimolecular reaction order look like?

rectangular hyperbola

what does the graph of a bimolecular reaction order look like?

saturation

why is the graph of a bimolecular reaction a rectangular hyperbola?

metabolism

what is defined as the entire network of chemical reactions carried out by living cells driven by thermodynamics?

metabolites

what are defined as intermediates/products in the degradation and synthesis of biopolymers?

degrade molecules to create smaller molecules and energy

what do catabolic reactions do?

synthesize molecules driven by energy caught in catabolic reactions

what do anabolic reactions do?

compartmentalization

how does a cell separate opposing metabolic processes, regulate local concentrations, and coordinate flow of substrates through ezymes?

glycolysis, pentose phosphate pathway, fatty acid biosynthesis, a lot of gluconeogenesis

what are some examples of metabolic reactions that occur in the cytosol?

citric acid cycle, ETC/oxidative phosphorylation, fatty acid oxidation, amino acid breakdown

what are some examples of metabolic reactions that occur in the mitochondrion?

acetyl-CoA

what is an example given as a VERY common intermediate that catabolic pathways converge on?

NADH, NADPH, FADH₂

what are the reduced cofactors often produced when Acetyl-CoA is oxidized that are then used to produce ATP?

carbon dioxide, formaldehyde, methane

what is the most, zero, and least oxidized form of carbon?

conversion to CO₂

what is the ultimate fate of carbon compounds consumed during catabolism?

the change in free energy is equal to the change in entropy minus (the temperature in degrees kelvin multiplied by the change in enthalpy)

what is the relationship between free energy, enthalpy, and entropy?

less than 0

what must delta G be for the reaction to be spontaneous and exergonic?

more than 0

what must delta G be for the reaction to be not spontaneous and endergonic?

delta G degree prime; 298 K or 25 degrees C, 1 atm, 1 M, pH = 7

what is the symbol for biological standard state? what is the standard temperature, pressure, solute concentration, and H⁺ concentration?

near zero

what delta G value means that a reaction is not a good site to control pathway flux (controlled by substrate/product concentration)

enzymes catalyzing reactions far from equilibrium (delta G is much smaller than zero)

what type of enzyme (with what delta G) is used as a chokepoint in pathway flux?

allosteric regulation

what type of regulation is when a product, substrate, or cofactor for the pathway binds to and regulates the rate-limiting enzyme?

covalent modification

what type of regulation involves the rate limiting enzyme’s specific residues being modified to alter enzyme activity? The modification reaction is often controlled by external signals.

enzyme phosphorylation

what is an example of covalent modification?

substrate cycling

what type of regulation involves the rates of two opposed non-equilibrium reactions catalyzed by two different enzymes being altered to control the flux?

genetic

what type of regulation involves transcription, protein translation, etc?

to use high energy intermediates to produce free energy currency

what is the function of catabolism?

phosphoryl group transfer (ATP), Acetyl/Acetyl CoA, Reduced cofactors

what are the three types of compounds produced to capture the release of free energy for use?

AMP and PP_i

what are the products left when the reaction cleaves the beta and gamma phosphate during phosphoryl group transfer of ATP?

phosphoester bond

what bond in ATP is not energetic due to its high stability?

electrostatic repulsion among negatively charged oxygens, solvation factors (increase entropy), resonance

what are the three sources of energy in phospho-anhydrides?