Chapter 3 Flashcards
prebiotic soup
a hypothetical solution of sugars, amino acids, nitrogenous bases, and other building blocks of larger molecules that may have formed in shallow waters or deep ocean vents of ancient earth and given rise to larger biological molecules
functional group
a small group of atoms bonded together in a precise configuration and exhibiting particular chemical properties that imparts to any any organic molecule in which it occurs
condensation reaction
a chemical reaction in which two molecules are joined covalently with the removal of an -OH from one and an -H from another to form water, also called dehydration reaction
hydrolysis
a chemical reaction in which a molecule is split into smaller molecules by reacting with with water, in biology, most hydrolysis reactions involve the splitting of polymers into monomers
endergonic
referring to a chemical reaction that requires an input of energy to occur
exergonic
referring to a chemical reaction that can occur spontaneously, releasing heat and/or increasing entropy
dimer
an association of two molecules which may be identical (homodimer) or different(heterodimer)
termination
in enzyme catalyzed reactions, the final stage in which the enzyme returns to its original conformation and products are released
polymerization
process of linking monomers together
oligopeptide
polypeptide with fewer than 50 amino acids linked together
Van der Waals interactions
the stabilization of hydrophobic side chains by the presence of an electrical attraction
activation energy
amount of free energy required to reach the transition state
active site
location where the substrates bind and react with an enzyme
induced fit
change in the shape of the active site of an enzyme as the result of an initial weak bonding of a substrate, so that it substrate more tightly
allosteric regulation
regulation of a proteins function by binding of a regulatory molecule usually to a specific site distinct from the active site causing a change in the protein’s shape
catalysis
acceleration of the rate of a chemical reaction due to a decrease in the free energy of the transition state, called the activation energy
competitive inhibition
inhibition of an enzyme’s ability to catalyze a chemical reaction via a nonreactant molecule that competes with the substrate for the active site
side chain
a group of atoms attached to the main part of a molecule and having a ring or chain structure
R group
any group in which a carbon or hydrogen atom is attached to the rest of the molecule
alpha helix
a protein secondary structure in which the polypeptide backbone coils into a spiral shape stabilized by hydrogen bonds between atoms
beta pleated sheets
a protein secondary structure in which the polypeptide backbone folds into a sheetlike shape stabilized by hydrogen bonding
denaturation
for a macromolecule, the loss of its 3D structure and biological activity due to the breaking of hydrogen and disulfide bonds, usually caused by extreme heat or pH levels
renaturation
The conversion of denatured protein or nucleic acid to its native configuration
lock and key model
an analogy where the lock is the enzyme and the key is the substrate. Only the correctly sized key (substrate) fits into the key hole (active site) of the lock (enzyme).
