Carbohydrates

Question 1

which diagrams have D & L glucose ?

Answer 1

fischer projection

Question 2

how to check for fischer projection for D & L configuration ?

Answer 2

2nd last C (at bottom) has OH on right side = D
on left = L

Question 3

How are the dissacharides sucrose, maltose & lactose formd?

Answer 3

sucrose = glucose + fructose
matlose = 2 glucose
lactose = glucose + galactose

Question 4

wht are the 2 polysaccharides of glucose?

Answer 4

starch, cellulose

Question 5

name 2 pairs of epimers

Answer 5

D-glucose & D-galactose
glucose & mannose
erythrose & threose

Question 6

epimer

Answer 6

same molecule with 1 bond rotation

Question 7

how to determine α & β carbohydrate from chair conformation ?

Answer 7

α = when CH2OH (on C-6) & OH (on C-1) is in different plane
β = same plane

Question 8

monosaccharide oxidation = ?

Answer 8

COOH (product)

Question 9

mono reduction = ?

Answer 9

OH [alcohol] by NaBH4

Question 10

mono esterification

Answer 10

COOR [ester]

Question 11

What happens when aldehyde, ketone, & terminal hydroxy group are oxidized?

Answer 11

COOH forms

Question 12

what happens in the reduction of :
1️⃣glucose
2️⃣galactose
3️⃣mannose
4️⃣fructose

Answer 12

it forms:
1️⃣sorbitol
2️⃣dulcitol
3️⃣manittol
4️⃣mannitol + sorbitol

Question 13

epimerization

Answer 13

forming 2 epimers

Question 14

enolate ion

Answer 14

C=C-O(minus)

Question 15

how to form a C-2 epimer of glucose

Answer 15

glucose ➡️ enolate ➡️ D-mannose
all same except C-2 OH position change

Question 16

what happens in Enediol rearrangement to turn glucose ➡️ fructose ?

Answer 16

aldehyde ➡️ ketone at C-2

Question 17

oligosaccharides

Answer 17

2 to 10 monosaccharide units
linked by glycosidic bonds

Question 18

other names for glucose

Answer 18

dextrose / blood sugar

Question 19

fructose common name

Answer 19

gruit sugar

Question 20

sucrose common name

Answer 20

table sugar

Question 21

Lactose common name

Answer 21

Milk sugar

Question 22

chiral C

Answer 22

C atom bonded to 4 different groups

Question 23

how are D & L molecules related?

Answer 23

They are stereoisomers and enantiomers to each other

Question 24

what is same & different in D & L isomers

Answer 24

same molecular formula
same connectivity of atoms
differ only in the spatial arrangement

Question 25

Which carbon is anomeric in Hawarth projection

Answer 25

C-1 (to the right of O in ring)
chiral C

Question 26

Which carbon is anomeric in chair conformation ?

Answer 26

C-1 to the right

Question 27

anomer

Answer 27

a special type of epimer of cyclic forms of carbohydrates that differ in configuration only at the anomeric carbon (C=O)(C-1)