L5: Amino Acid Structure & Function

Question 1

what does an AA look like at physiological pH?

Answer 1

zwitterionic form

• -amine group is protonated
• -carboxyl group is deprotonated

Question 2

define zwitterionic form

Answer 2

zwitter = 2
2 ions on one compound at physiologic pH

they cancel each other out

Question 3

chiral centers – 2 enantiomers possibilities

Answer 3

L - left handed
D - right handed

alanine has 2 enantiomers

Question 4

list the positively charged amino acids

Answer 4

lysine
arginine
histidine

Question 5

list the negatively charged amino acids

Answer 5

aspartic acid

glutamic acid

Question 6

tiny amino acids

Answer 6

alanine
glycine
cysteine
serine

Question 7

very large amino acids

Answer 7

tryptophan
phenylalanine
tyrosine

Question 8

what is the difference between essential and nonessential amino acids

Answer 8

essential = humans cannot synthesize - must get it from diet

Question 9

what nonessential amino acid is made thru secondary synthesis

Answer 9

tyrosine

Question 10

what essential amino acids have greater consumption than production

Answer 10

methionine

arginine

Question 11

how many natural amino acids are there ?

Answer 11

20

Question 12

what is the 21st amino acid?

Answer 12

selenocysteine
Sec
U

Question 13

what is the 22nd amino acid?

Answer 13

pyrrolysine
Pyl
O

Question 14

selenoproteins

Answer 14

• -important for good health
• -reduce oxidative stresses in conjunction w/ vit E
• -required in cerebellum neurons for growth and coordination
• -moderate inflammatory responses

Question 15

selenium deficiency can result in ?

Answer 15

cardiac problems

Question 16

too much selenium in body

Answer 16

1. hair/nail brittleness
2. garlic breath
3. GI/neurological lesions
4. renal failure, death

Question 17

presence of the 21st and 22nd amino acids

Answer 17

21st in all 3 domains of life

22 only in some prokaryotes

Question 18

proteinogenic amino acids

Answer 18

incorporated into proteins during translation

codons to expand genetic code
UAG, UGA, UAA

Question 19

nonproteinogenic amino acids can be used during _________ synthesis?

Answer 19

non-ribosomal protein synthesis - NRPS

Question 20

nonproteinogenic amino acids are not used for ?

Answer 20

to make proteins

Question 21

nonproteinogenic amino acids functions

Answer 21

1. metabolism intermediates
2. physiolgocial roles
3. pre-biotic

Question 22

physiological roles of nonproteinogenic amino acids

Answer 22

bacteria cell wall
NTs
toxins/antimicrobials

Question 23

primary structure of proteins

Answer 23

chain of amino acids

Question 24

secondary structure of proteins

Answer 24

local folding of the polypeptide chain

Question 25

tertiary structure of proteins

Answer 25

folding of the secondary structure

Question 26

quarternary structure of proteins

Answer 26

interaction of multiple peptides

Question 27

peptide bond is between

Answer 27

N-C

Question 28

peptide bond is a single bond meaning?

Answer 28

possibility for rotation