4 - Amino Acids

Question 1

What amino acid is not chiral

Answer 1

Glycine

Question 2

What are the 3 major purposes of Amino Acids

Answer 2

(1) Generation of Energy (2) Protein Synthesis (3) Synthesis of Heme, Purines, Melanin, Pyrimidines

Question 3

α amino acids means

Answer 3

the amino and carboxyl group is
attached to the same carbon
atom (called the α carbon)

Question 4

β amino acids means

Answer 4

theamino group is attached to the
second carbon away from the
carboxyl group (called the β
carbon)

Question 5

What Amino acid does not have a Beta

Answer 5

Glycine

Question 6

Only what isomer and what form is used in natural proteins

Answer 6

L isomer and α Form

Question 7

D-Amino acids govern

Answer 7

stationary phase cell wall remodeling in bacteria

Question 8

D amino acids also appear to do what

Answer 8

Appear to modulate synthesis of

peptidoglycan

Question 9

D-Met and D-Leu

Answer 9

Vibrio cholerae

Question 10

D-Tyr and D-Phe

Answer 10

Bacillus subtilis

Question 11

What form of the peptide bond is favored

Answer 11

Trans

Question 12

The peptide bond is metastable and
hydrolyzes in an aqueous environment
only in the presence

Answer 12

of a catalyst

Question 13

What determines how a protein will fold

Answer 13

Side chains

Question 14

The 3 characteristics of Branched Chain AA

Answer 14

• Very nonpolar
(hydrophobic) R
groups
• Contribute greatly to
the hydrophobic
effect which drives
protein folding
• Found in the interior
of proteins

Question 15

What are the 3 branched chain AA

Answer 15

Isoleucine, Leucine, Valine

Question 16

What are the hydroxyl AA

Answer 16

Serine and Threonine

Question 17

R groups contribute heavily to the formation of

Answer 17

hydrogen bonds

Question 18

Hydroxyl AA also form bonds with

Answer 18

– Carbohydrates in
glycoproteins
– Phosphate in
phosphoproteins

Question 19

What are the sulfur containing AA

Answer 19

Cysteine and Methionine

Question 20

Disulfide bonds are very

important in

Answer 20

3D Structure

Question 21

Insulin is made up of

Answer 21

2 peptide chains joined

together by 3 disulfide bonds

Question 22

Sulfur containing AA are very hydrophobic or hydrophilic

Answer 22

Hydrophobic

Question 23

Sulfur containing AA are participate as

Answer 23

Free Radical Scavenger

Question 24

What is the precursor of
the methyl group donor S -
adenosylmethionine (SAM)

Answer 24

Methionine

Question 25

What are the aromatic AA

Answer 25

Phenylalanine, Tyrosine, Tryptophan

Question 26

Aromatic amino acids are | usually sequestered in the what

Answer 26

Interior of protein

Question 27

hydrophobic effect is quite substantial in stabilizing the 3-D structure by

Answer 27

by lowering the free energy involved in folding

Question 28

What 2 Aromatic AA can form hydrogen bonds

Answer 28

Tyrosine and tryptophan

Question 29

Both tryptophan and tyrosine absorb

Answer 29

UV Light

Question 30

Acidic Amino Acids 4 functions

Answer 30

* Serve as proton donors * Help make proteins more hydrophilic * Can also make hydrogen bonds * Help maintain the pH in active sites

Question 31

What are the acidic amino acids

Answer 31

Aspartate, Asparagine, Glutamate, Glutamine

Question 32

What are the basic amino acids

Answer 32

Lysine, Arginine, Histidine

Question 33

Basic amino acid functions

Answer 33

``` • Serve as proton acceptors • Contribute somewhat to the pH • Can help activate substrates for enzymes by abstracting a proton ```

Question 34

What does proline do to chain

Answer 34

Introduces kinks into protein chain due to its bent structure

Question 35

Isoelectric point is

Answer 35

point at which there is no net charge (pI)

Question 36

Amino acid modifications can be used to tag proteins for

Answer 36

degradation

Question 37

What are the types of amino acid modifications

Answer 37

* Glycosylation * Fatty Acylation or Prenylation * Regulatory modifications

Question 38

Essential AA means that

Answer 38

Cannot be synthesized by human body, must get from diet

Question 39

What are the essential AA

Answer 39

* Valine * Threonine * Leucine * Methionine * Isoleucine * Lysine * Phenylalanine * Histidine * Tryptophan

Question 40

All amino acids except what two are at least partially glucogenic

Answer 40

Lysine and Leucine

Question 41

What are the only amino acids that are solely ketogenic

Answer 41

Lysine and Leucine

Question 42

What doe Lysine and Leucine give rise to

Answer 42

acetylCoA or acetoacetylCoA

Question 43

What amino acids give rise to both glucose and fatty acid precursors and are thus glucogenic and ketogenic

Answer 43

isoleucine, phenylalanine, threonine, tryptophan, and tyrosine

Question 44

Tyrosine is the precursor to

Answer 44

(1) Dopamine (2) Epinephrine (3) Tyrosine

Question 45

Tryptophan is the precursor to

Answer 45

Serotonin

Question 46

Phenylalanine is the precursor to

Answer 46

Dopamine

Question 47

Glycine Degradation is carried out by

Answer 47

Glycine cleaving enzyme

Question 48

Deficiency in Glycine cleaving enzyme can cause

Answer 48

Nonketotic hyperglycinemia

Question 49

Nonketotic hyperglycinemia causes

Answer 49

death infancy or profound mental retardation in | survivors

Question 50

Glycine can also be converted into

Answer 50

Oxalate (which is found in most kidney stones)

Question 51

Deficiency in cystathionine synthase will lead to

Answer 51

Leads to accumulation of homocysteine and | methionine

Question 52

How is def in cystathionine synthase treated

Answer 52

restricting dietary methionine and adding folic | acid supplements

Question 53

Maple Syrup Urine Disease is a disorder with a deficiency in what

Answer 53

branched chain α keto acid dehydrogenase

Question 54

Complete deficiency of branched chain α keto acid dehydrogenase leads to

Answer 54

– Severe mental retardation – Acidosis – Sweet odor to urine – Early death

Question 55

What supplement is sometimes useful for treating Maple Syrup Urine Disease

Answer 55

Thiamine

Question 56

Phenylketonuria is caused by

Answer 56

complete lack of phenylalanine hydroxylase

Question 57

With phenylketonuria, why are there no abnormalities at birth

Answer 57

because phenylalanine and metabolites are transferable across placenta

Question 58

Why do pts with PKU have a lighter complexion

Answer 58

Phenylalanine cannot be converted to Tyrosine which is a precursor to melanin

Question 59

PKU can be treated by

Answer 59

severely restricting dietaryphenylalanine

Question 60

In PKU what is also hazardous to the pt

Answer 60

Aspartame

Question 61

Why can the special diet in PKU be tapered off in adolescents

Answer 61

Only developing brain is vulnerable to | PKU