Chapter 19- Amino Acids And Proteins

Question 1

Acidic amino acid

Answer 1

An amino acid has an R group with a carboxylate (-COO) ion

Question 2

A (alpha) helix

Answer 2

A secondary level of protein structure, in which hydrogen bonds connect the N-H of one peptide bond with the ( C=O) of a peptide bond further down the chain to form a coiled or corkscrew structure

Question 3

A-keratins

Answer 3

Fibrous proteins containing mostly a Helixes found in hair,nails, and skin

Question 4

Amino acids

Answer 4

The building block of proteins, consisting of an ammonium group,ma carboxylate group, and a unique R group attached to the a carbon

Question 5

Basic amino acid

Answer 5

An amino acid that contains an R group with an ammonium (-NH3+) ion

Question 6

B-pleated sheet

Answer 6

A secondary level of protein structure that consists of hydrogen bonds between peptide links in parallel polypeptides

Question 7

C terminal

Answer 7

The end amino acid In a peptide chain with a free carboxylate (-COO) group

Question 8

Collagen

Answer 8

The most abundant form of protein in the body, which is composed if fibrils of triple Helixes with hydrogen bonding between the -OH groups ofnhydroxyproline and hydroxylisine

Question 9

Denaturation

Answer 9

The loss of secondary or tertiary protein structure caused by heat, acids, bases, organic compounds, heavy metals, and/or agitation

Question 10

Disulfide bond

Answer 10

Covalent -S-S- bonds that firm between the -SH groups of two cysteines in a protein to stabilize the tertiary structure

Question 11

Electrophoresis

Answer 11

The use of electrical current to separate proteins or other charged molecules with different isoelectric points

Question 12

Essential amino acids

Answer 12

Amino acids that must be supplied by the diet because they are not synthesized by the body

Question 13

Fibrous proteins

Answer 13

Proteins that are insoluble in water; consisting of polypeptide chains with a- Helixes or b-pleated sheets, and comprising with fibers of hair, skin, nails, and silk

Question 14

Globular proteins

Answer 14

Proteins that acquire a compact shape from attractions between the R groups of the amino acids in the protein

Question 15

Hydrogen bonds

Answer 15

The interactions between water and the polar R groups such as -OH, -NH2, and -COOH on the outside surface of polypeptide chain

Question 16

Hydrophilic reactions

Answer 16

The attractions between polar R groups on the protein surface and water

Water attracting

Question 17

Hydrophobic interactions

Answer 17

The attractions between non polar R groups on the inside of a globular protein

Water fearing

Question 18

Isoelectric point (pI)

Answer 18

The pH at which amino acid exists as a zwitterion with a net charge of zero

Question 19

N terminal

Answer 19

The end amino acid in a peptide with a free -NH3+ group

Question 20

Nonpolar amino acids

Answer 20

Amino acids with Nonpolar R groups containing only C and H atoms

Question 21

Peptide

Answer 21

The combination of two or more amino acids joined by peptide bonds; di peptide, tripeptide, and so on

Question 22

Polar amino acids (neutral)

Answer 22

Amino acids with polar R groups

Question 23

Primary structure

Answer 23

The specific sequence of the amino acids in a protein

Question 24

Protein

Answer 24

Polypeptides containing many amino acids linked together by peptide bonds that are biologically active

Question 25

Quaternary structure

Answer 25

A protein structure in which two or more protein subunits form an active protein

Question 26

Salt bridge

Answer 26

The attraction between the ionized R groups of basic and acidic amino acids in the tertiary structure of a protein

Question 27

Secondary structure

Answer 27

The formation of an a-helix, b-pleated sheet, or triple helix

Question 28

Tertiary structure

Answer 28

The folding of the secondary structure of a protein into a compact structure that is stabilized by the interactions of R groups such as ionic and disulfide bonds

Question 29

Triple helix

Answer 29

The protein structure found in collagen consisting of three polypeptide chains woven together like a braid

Question 30

Zwitterion

Answer 30

The diplomat form of an amino acid consisting of two oppositely charged ionic regions, -NH3+, and -COO