biochem final Flashcards
(52 cards)
configuration versus conformation
confirmation is the spatial arrangement of substituent groups that are free to assume different positions in space. configuration is
enantiomers exhibit optical activity. What type of mixture shows no optical activity?
a racemic mixture, (equimolar solution of two enantiomers) shows no optical rotation
stereospecificity
the ability to distinguish between stereoisomers
isolated versus closed system
isolated = system exchanges neither matter nor energy with its surroundings
closed system = system exchanges energy but not matter with its surroundings
what does an open system exchange with its surroundings
both energy and matter
a living organism is an example of a(n) _____ system
open
first law of thermodynamics
total amount of energy in the universe is constant
measure of total energy change in a chemical reaction, a measure of number and kinds of bonds broken
∆H, enthalpy
gibbs free energy equation
∆𝐺=∆𝐻−𝑇∆𝑆
what does the gibbs free energy tell us
It relates the change in enthalpy and entropy that take place during a reaction at a specific temperature
spontaneous reactions occur when ∆G is
negative
if ∆G is positive, that means that the reaction
cannot proceed spontaneously
T/F In some cases, spontaneity depends on temperature
true
coupling reactions couple _____ and ______ reactions
endergonic and exergonic
the breakage of phosphoanhydride bonds in ATP is
highly exergonic
in closed systems, chemical reactions proceed spontaneously until
equilibrium is reached
If under a given set of conditions, the reaction A → B occurs with ∆G = –14 kJ/mol and the reaction C → B occurs when ∆G = +16 kJ/mol, then:
A. the conversion of C to A is freely reversible.
B. the conversion of A to C is exergonic.
C. A and C can never be at equilibrium, even under different
reaction conditions.
D. the conversion of A to C is entropically driven.
b
mass-action ratio, Q
ratio of product concentrations to reactant concentrations at a given time can be calculated to determine how far the reaction is from equilibrium
overall network of enzyme-catalyzed pathways, both catabolic and anabolic, is defined as_____________
metabolism
pathways of enzyme-catalyzed reactions that act on the main constituents of cells—proteins, fats, sugars, and nucleic acids—are nearly identical in all living organisms is __________
unity of life
____________=keeps the production and utilization of each metabolic intermediate in balance
feedback inhibition
non-covalent interactions strongest to weakest
ionic, dipole, van der waals, hydrophobic
why are non-covalent interactions important
they are individually weak, allowing for flexibility of structure and interactions, but they are strong collectively allowing for stability
most stable structures maximize _______ interactions
weak
