Amino Acids

Question 1

What functional groups are present in amino acids?

Answer 1

Amino group and carboxyl group bonded to the a-carbon

Question 2

a portion of an amino acid that determines its identity

Answer 2

Side chain

Question 3

-NH2 functional group

Answer 3

Amino group

Question 4

-COOH functional group that disassociates to give the carboxylate anion, -coo-, and a hydrogen ion

Answer 4

Carboxyl group

Question 5

molecules that differ from each other only in their configuration

Answer 5

Stereoisomers

Question 6

What is the configuration of the vast majority of a-amino acids?

Answer 6

L-configuration at the a-carbon

Question 7

What is the usual form of proline?

Answer 7

L form

Question 8

What is the three-letter abbreviation and one-letter abbreviation of alanine?

Answer 8

Ala, A

Question 9

What is the three-letter abbreviation and one-letter abbreviation of arginine?

Answer 9

Arg, R

Question 10

What is the three-letter abbreviation and one-letter abbreviation of asparagine?

Answer 10

Asn, N

Question 11

What is the three-letter abbreviation and one-letter abbreviation of aspartic acid?

Answer 11

Asp, D

Question 12

What is the three-letter abbreviation and one-letter abbreviation of cysteine?

Answer 12

Cys, C

Question 13

What is the three-letter abbreviation and one-letter abbreviation of glutamic acid?

Answer 13

Glu, E

Question 14

What is the three-letter abbreviation and one-letter abbreviation of glutamine?

Answer 14

Gln, Q

Question 15

What is the three-letter abbreviation and one-letter abbreviation of histidine?

Answer 15

His, H

Question 16

What is the three-letter abbreviation and one-letter abbreviation of glycine?

Answer 16

Gly, G

Question 17

What is the three-letter abbreviation and one-letter abbreviation of isoleucine?

Answer 17

Ile, I

Question 18

What is the three-letter abbreviation and one-letter abbreviation of leucine?

Answer 18

Leu, L

Question 19

What is the three-letter abbreviation and one-letter abbreviation of lysine?

Answer 19

Lys, K

Question 20

What is the three-letter abbreviation and one-letter abbreviation of methionine?

Answer 20

Met, M

Question 21

What is the three-letter abbreviation and one-letter abbreviation of phenylalanine?

Answer 21

Phe, F

Question 22

What is the three-letter abbreviation and one-letter abbreviation of proline?

Answer 22

Pro, P

Question 23

What is the three-letter abbreviation and one-letter abbreviation of serine?

Answer 23

Ser, S

Question 24

What is the three-letter abbreviation and one-letter abbreviation of threonine?

Answer 24

Thr, T

Question 25

What is the three-letter abbreviation and one-letter abbreviation of tryptophan?

Answer 25

Trp, W

Question 26

What is the three-letter abbreviation and one-letter abbreviation of tyrosine?

Answer 26

Tyr, Y

Question 27

What is the three-letter abbreviation and one-letter abbreviation of valine?

Answer 27

Val, V

Question 28

What are the 9 nonpolar amino acids?

Answer 28

Glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, tryptophan, and methionine

Question 29

Which amino acids contain aliphatic hydrocarbon group?

Answer 29

alanine, valine, leucine, isoleucine

Question 30

Which amino acid has an aliphatic cyclic structure?

Answer 30

Proline

Question 31

Which amino acid has a hydrocarbon group that is aromatic?

Answer 31

Phenylalanine

Question 32

Which amino acid has a side chain that contains an aromatic indole ring?

Answer 32

Tryptophan

Question 33

Which amino acid has a side chain that contains a sulfur atom addition to aliphatic hydrocarbon groupings?

Answer 33

Methionine

Question 34

What are the 6 polar-neutral amino acids?

Answer 34

Serine, threonine, tyrosine, cysteine, glutamine, and asparagine

Question 35

Which two amino acids have a polar group (-OH) bonded to aliphatic hydrocarbon groups?

Answer 35

Serine and threonine

Question 36

Which amino acid has a hydroxyl group (phenol) that is bonded to an aromatic hydrocarbon group?

Answer 36

Tyrosine

Question 37

Which amino acid has a polar side chain that contains a thiol group (SH)?

Answer 37

Cysteine

Question 38

Which two amino acids contain amide groups in their side chains?

Answer 38

Glutamine and asaparagine

Question 39

What are the two acidic amino acids?

Answer 39

glutamic acid and aspartic acid

Question 40

_____ can lose a proton, forming carboxylate anions

Answer 40

carboxyl group

Question 41

Side chains of acidic amino acids are _____ charged at _____ pH

Answer 41

negatively, neutral

Question 42

the average pKa of a-carboxyl group

Answer 42

2.19

Question 43

Greater acidity is due to _____

Answer 43

the electron-withdrawing inductive effect of the -NH3+ group

Question 44

What is the pKa of secondary alkylammonium ion?

Answer 44

10.76

Question 45

Average value of pKa of an a-NH3+ group

Answer 45

9.47

Question 46

What are the 3 basic amino acids?

Answer 46

Histidine, lysine, arginine

Question 47

Side chains of basic amino acids are _____ charged at _____ pH

Answer 47

positively, near neutral pH 7

Question 48

Which amino acid has a side chain attached to an aliphatic hydrocarbon chain?

Answer 48

lysine

Question 49

Which amino acid has a side chain that is a guanidino group bonded to an aliphatic hydrocarbon chain?

Answer 49

arginine

Question 50

Side chains of arginine that is a considerably stronger base than an aliphatic amine

Answer 50

guanidine

Question 51

Basicity of the guanidino group is attributed to _____

Answer 51

the large resonance stabilization of the protonated form relative to the neutral form

Question 52

Side chain of histidine is a heterocyclic aromatic amine

Answer 52

Imidazole group

Question 53

Ratio of uncharged to charged side chains at pH 7.0

Answer 53

10:1 because the pH is one unit higher than the pKa