Chapter 14

Question 1

active site

Answer 1

The location on the surface of an enzyme where the substrates bind to the enzyme and the reaction occurs

Question 2

activity

Answer 2

The number of reaction cycles that an enzyme catalyzes per second

Question 3

alpha carbon

Answer 3

The carbon atom in an amino acid that is between the carboxyl group and the amino group

Question 4

alpha helix

Answer 4

A protein structure in which the polypeptide backbone folds into a tight coil

Question 5

amino acid

Answer 5

An organic compound that contains an amino group and a carboxyl group separated by one carbon atom

Question 6

beta sheet

Answer 6

Protein structure in which the polypeptide backbone folds into a set of parallel strands

Question 7

coenzyme

Answer 7

An organic molecule that is required by an enzyme

Question 8

cofactor

Answer 8

Any substance that is required by an enzyme

Question 9

competitive inhibitor

Answer 9

A molecule that fits into the active site of an enzyme and prevents the normal substrate from entering

Question 10

C-terminal amino acid

Answer 10

The amino acid that contains a free carboxyl group in a polypeptide

Question 11

Denature

Answer 11

To change the way a polypeptide is folded, normally rendering the polypeptide inactive

Question 12

effector

Answer 12

A molecule or ion that binds an enzyme outside of the active site and changes the activity of the enzyme

Question 13

enzyme-product complex

Answer 13

The combination of an enzyme and the products of the reaction it catalyzes, while the products remain in the active site.

Question 14

enzyme-substrate complex

Answer 14

the combination of an enzyme and the reactants of the reaction it catalyzes. The reactant molecules bound to active site

Question 15

essential amino acid

Answer 15

An amino acid that humans cannot make from other nutrients and must be present in a diet

Question 16

hydrophilic interaction

Answer 16

The attraction of hydrophilic amino acid side chains to the water molecules that surround a protein

Question 17

hydrophobic interaction

Answer 17

The tendency of hydrophobic amino acid side chains to cluster in the center of a protein, avoiding surrounding water molecules

Question 18

nitrogen cycle

Answer 18

The series of chemical and biological reactions that interconvert N2, inorganic ions such as NH4 and NO3-

Question 19

nitrogen fixation

Answer 19

The reactions that convert N2 into nitrogen containing compounds

Question 20

nonessential amino acid

Answer 20

An amino acid that humans can make from other nutrients

Question 21

N-terminal amino acid

Answer 21

The amino acid that contains a free amino group in a polypeptide

Question 22

peptide bond

Answer 22

The covalent bond between nitrogen and carbon that links consecutive amino acids into polypeptide

Question 23

Peptide group

Answer 23

The amide group that links consecutive amino acids in a polypeptide

Question 24

polypeptide

Answer 24

A molecule that is built from amino acids linked by peptide bonds; a protein

Question 25

primary structure

Answer 25

The sequence of amino acids in a polypeptide

Question 26

Protein

Answer 26

A large molecule composed of one or more chains of amino acids in a specific order.

Question 27

quaternary structure

Answer 27

The way that two or more polypeptide chains bing together to form an active protein

Question 28

secondary structure

Answer 28

The coiling or folding of a polypeptide chain that is a result of hydrogen bonding between peptide groups

Question 29

side chain

Answer 29

The portion of an amino acid that distinguishes it from other amino acids

Question 30

substrate

Answer 30

A reactant in a reaction that is categorized by an enzyme

Question 31

tietiary structure

Answer 31

The folding of a polypeptide chain that is a result of interacting involving amino acid side chains

Question 32

triple helix

Answer 32

A protein structure in which three polypeptide chains coil around one another

Question 33

urea cycle

Answer 33

The sequence of reactions by which humans convert ammonium ions into urea