Chapter 3

Question 1

prebiotic soup

Answer 1

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

Question 2

functional group

Answer 2

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

Question 3

condensation reaction

Answer 3

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

Question 4

hydrolysis

Answer 4

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

Question 5

endergonic

Answer 5

referring to a chemical reaction that requires an input of energy to occur

Question 6

exergonic

Answer 6

referring to a chemical reaction that can occur spontaneously, releasing heat and/or increasing entropy

Question 7

dimer

Answer 7

an association of two molecules which may be identical (homodimer) or different(heterodimer)

Question 8

termination

Answer 8

in enzyme catalyzed reactions, the final stage in which the enzyme returns to its original conformation and products are released

Question 9

polymerization

Answer 9

process of linking monomers together

Question 10

oligopeptide

Answer 10

polypeptide with fewer than 50 amino acids linked together

Question 11

Van der Waals interactions

Answer 11

the stabilization of hydrophobic side chains by the presence of an electrical attraction

Question 12

activation energy

Answer 12

amount of free energy required to reach the transition state

Question 13

active site

Answer 13

location where the substrates bind and react with an enzyme

Question 14

induced fit

Answer 14

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

Question 15

allosteric regulation

Answer 15

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

Question 16

catalysis

Answer 16

acceleration of the rate of a chemical reaction due to a decrease in the free energy of the transition state, called the activation energy

Question 17

competitive inhibition

Answer 17

inhibition of an enzyme’s ability to catalyze a chemical reaction via a nonreactant molecule that competes with the substrate for the active site

Question 18

side chain

Answer 18

a group of atoms attached to the main part of a molecule and having a ring or chain structure

Question 19

R group

Answer 19

any group in which a carbon or hydrogen atom is attached to the rest of the molecule

Question 20

alpha helix

Answer 20

a protein secondary structure in which the polypeptide backbone coils into a spiral shape stabilized by hydrogen bonds between atoms

Question 21

beta pleated sheets

Answer 21

a protein secondary structure in which the polypeptide backbone folds into a sheetlike shape stabilized by hydrogen bonding

Question 22

denaturation

Answer 22

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

Question 23

renaturation

Answer 23

The conversion of denatured protein or nucleic acid to its native configuration

Question 24

lock and key model

Answer 24

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).