Amino Acids

Question 1

What amino acids are not found in alpha helices and why?

Answer 1

Proline and Glycine

Proline has a rigid structure. The amide group is contained within a ring structure so unable to hydrogen bond

Glycine is small and very flexible. but also super floppy so not good for alpha-helices

Question 2

N-linked carbohydrates

Answer 2

Added to asparagine in the ER
adds glycan (sugar)
Important for structure and function

Question 3

ketogenic amino acids

Answer 3

can be converted into acetyl CoA and ketone bodies through transamination or deamination

leucine and lysine are the amino acids that are solely ketogenic

form acetoacetate and acetyl CoA

tryptophan, tyrosine, phenylalanine, isoleucine, and threonine are both ketogenic and glucogenic

LIFT WYK (lindsey is freaking tired, watch your krap)

Question 4

glucogenic amino acids

Answer 4

can be converted into glucose through gluconeogenesis

also form pyruvate, alpha ketoglutarate, succinyl Co-A, fumarate, or oxaloacetate

all amino acids except for leucine and lysine

LIFT WYK are glucogenic and ketogenic

Question 5

What is required for a glycoprotein or glycolipid to be reduced?

Answer 5

for there to be a free anomeric carbon that can be oxidized

nonreducing cyclic are ketal/acetyl
reducing cyclic are hemiacetyl/hemiketal

Question 6

What is a conservative mutation for glycine?

Answer 6

Alanine, Valine, Leucine, and Isoleucine

Question 7

What is a conservative mutation for serine?

Answer 7

threonine

Question 8

What is a conservative mutation for Asparagine

Answer 8

Glutamine

Question 9

What is a conservative mutation for Phenylalanine

Answer 9

Tryptophan

Question 10

What is a conservative mutation for lysine?

Answer 10

arginine

Question 11

What is a conservative mutation for aspartate

Answer 11

glutamate

Question 12

acid hydrolysis + heat

Answer 12

will break peptide bonds non specifically

Question 13

proteolysis

Answer 13

specific cleavage of peptides
occurs with help of enzyme protease

ex: trypsin which is released by the pancreas to help with digestion

Question 14

what is the molecular weight of amino acids?

Answer 14

110 Da aka 110 g/mol

Question 15

What is the conversion between Da and g/mol

Answer 15

1:1 ratio

Question 16

Which amino acids can be phosphorylated?

Answer 16

serine, threonine, and tyrosine

because they all have available OH

this changes them from neutral to negatively charged

Question 17

Which amino acids can mimic the effects of amino acids that can be phosphorylated?

Answer 17

glutamate (E) and aspartate (D)

Question 18

what occurs when a solution has a high salt concentration?

Answer 18

NaCl is a neutral salt which can disrupt salt bridges by forming ionic bonds with amino acids

it can also disrupt hydrogen bonding

Question 19

electrostatic interactions

Answer 19

ionic bonds are noncovalent forces that help maintain the tertiary and quaternary structure of a protein

Question 20

ubiquitin

Answer 20

targets proteins to proteosome for degradation

usually linked to lysine

Question 21

ionizable amino acid side chains

Answer 21

K, H, R, E, D, C, Y

are altered as protons are added or removed

K, H, R –> increase PI

E, D, C, Y –> decrease PI

Question 22

alipathic amino acids

Answer 22

nonpolar and hydrophobic

single, branched, or cyclic (non aromatic) carbon backbone

proline, methionine, alanine, valine, isoleucine, leucine

Question 23

why isn’t glycine considered an alipathic amino acid?

Answer 23

because glycine is too small

hydrophobicity increases the longer the carbon side chain. Although glycine is non-polar, it only has an H atom as its R Group

Question 24

protease

Answer 24

breaks apart peptide bonds

hydrolysis reaction - requires water to be added to create carboxylic acid and amine

Question 25

peptide bonds

Answer 25

group of amino acids strung together and connected via condensation reaction and broken by protease

they have some double bond character because the amide nitrogen has a lone electron pair that allows the peptide bond to exist in 2 resonance structures and therefore has restricted rotation and will be planar

Question 26

peptide hydrolysis

Answer 26

thermodynamically favorable but kinetically slow without a protease

usually water is added and a protease cleaves the peptide bond into individual amino acids

Question 27

What amino acids are both glucogenic and ketogenic?

Answer 27

LIFT WYK

leucine, isoleucine, phenylalanine, threonine, tryptophan, tyrosine, lysine