34-35

Question 1

animal amino acids are…

Answer 1

L configuration (“animals Love amino acids”)

except Cysteine is R

some bacteria have D-amino acids in specialized structures/bacterial cell walls

Question 2

naturally occurring carbs are…

Answer 2

D configuration (“Damn carbs/sugars”)

Question 3

all L carbs are built from a L-(-)-Glyceraldehyde, even if its optical activity is no longer (-)

Answer 3

L and D tell us about the precursor molecule

Question 4

how are AAs made in lab?

Answer 4

Strecker synthesis, Gabriel synthesis

Question 5

strecker synthesis

Answer 5

aldehyde becomes racemic alpha-amino acid

Ammonium (NH4 Cl) and cyanide (Na CN) are used

Step 1: aldehyde reacts with ammonia to form imine
Step 2: imine acquires a hydrogen from HCN, which makes the imine-carbon attractive to the CN, leading to formation of alpha-amino nitrile
Step 3: acid-catalyzed hydrolysis leaves us with alpha amino acid

Question 6

gabriel-malonic ester synthesis

Answer 6

racemic alanine is produced

phthalimide is deprotonated, becoming a strong nucleophile, displacing bromide from alpha-bromomalonic ester

addition of NaOMe and CH3BR, with acid and heat decarboxylation, form the final product

Question 7

henderson hasselbalch equation

Answer 7

pH = pKa + log ( base / acid )

Question 8

pI

Answer 8

the balance point of the positive and negative charge,

average the pKas of the two functional groups

Question 9

gel EP

Answer 9

based on CHARGE

Question 10

phenylalanine

Answer 10

VERY HYDROPHOBIC

Question 11

DCC coupling

Answer 11

synthesize peptides

Question 12

total acids and bases functional groups in a peptide chain

Answer 12

COUNT THE ENDS (1 base, 1 acid)

Question 13

THERE IS NO ROTATION AROUND A PEPTIDE BOND

Answer 13

see resonance of carbonyl carbon and nitrogen donates pair of electrons

Question 14

amino acids are thermodynamically favored over peptide chains, but kinetics is slow

hydrolysis of polysaccharides is thermodynamically favored (energy is REQUIRED for polysaccharide synthesis)

Answer 14

we can use strong acids and proteolytic enzymes to cleave peptide bonds (and heat)

Question 15

ketohexose

Answer 15

KETONE, no aldohexose

Question 16

epimer

Answer 16

reserved for SUGARS with more than 1 chiral center

Question 17

C1 is the anomeric carbon

Answer 17

conversion between two anomers is called MUTAROTATIONS

equatorial is more stable

Question 18

glycosidic linkages

Answer 18

covalent bond formed by dehydration that requires enzymatic catalysis

Question 19

starch and glycogen are similar

Answer 19

alpha 1,4 and alpha 1,6

Question 20

Benedict’s test

Answer 20

detects carbonyl units of sugars, distinguishing hemiacetals from acetals

monosaccharide = hemiacetal = POSITIVE Benedict’s test

acetal = LOCKED = NEGATIVE benedict’s

aldehydes, ketones, and hemiacetals give positive result in Benedict’s test for reducing sugars; acetals give a negative result since they are not reducible, and are not in equilibrium with open chain (carbonyl) form

Question 21

all monosaccharides are reducing sugars (?)

Answer 21

reduces Cu2+ to Cu

the reducing sugar is oxidized

Question 22

sucrose is NOT reducing

Answer 22

the 1,2 means they are joined at their anomeric carbons

ketose (2nd carbon is anomeric)

Question 23

soaps

Answer 23

sodium salts of fatty acids (RCOO- Na+)

amphipathic

Question 24

solvation shell

Answer 24

DECREASES entropy, surrounded the hydrophobic object

Question 25

phopholipids

Answer 25

diacylglycerol phosphate (DRAW)

formed from esterification of choline molecule to the phosphate group of DG-P

Question 26

fatty acids form MICELLES

Answer 26

phospholipids form lipid bilayers

Question 27

Fat

Answer 27

triacylglycerides

Question 28

Na BH4

Answer 28

reducing agent

Question 29

Aldehyde is oxidized to carboxylic acid

Answer 29

which reduces Cu+

Question 30

amphoteric

Answer 30

acid and base

Question 31

amphipathic

Answer 31

hydrophilic and hydrophobic (Soaps)