8-carbohydrates (midterm 2 cutoff) Flashcards
(95 cards)
1
Q
what is the general formula of carbohydrates
A
(CH2O)n
2
Q
what are some other elements that can be found in carbohydrates
A
N S P
3
Q
what are carbohydrates (definition)
A
polyhydroxy aldehydes or ketones
4
Q
what are 4 roles of carbohydrates
A
- fuel source/storage
- structural compounds
- recognition/regulation of extracellular proteins
- nucleic acid structure
5
Q
are monosaccharides water soluble
A
yes
6
Q
are disaccharides water soluble
A
yes
7
Q
are oligosaccharides water soluble
A
yes
8
Q
are homopolysaccharides water soluble
A
no
9
Q
are heterpolysaccharides water soluble
A
no
10
Q
what are homopolysaccharides and heteropolysaccharides
A
polymers of one or more carbohydrate unit, large and insoluble
11
Q
what are glycoconjugates
A
carbohydrates joined to other molecular classes
12
Q
what are 4 examples of glycoconjugates
A
proteoglycans, glycoproteins, peptidoglycan, glycolipids
13
Q
what is a monosaccharide
A
aldehyde or ketone with two or more hydroxyl groups
14
Q
what kind of chain is in monosaccharides and how are they connected
A
ubranched chains connected by single bonds
15
Q
what is the chirality of monosaccharides
A
multiple chiral carbons
16
Q
what is an aldose
A
when C1 has a carbonyl
17
Q
what is a ketose
A
when C2 has a carbonyl
18
Q
how do you name monosaccharides
A
based on the number of carbon atoms
19
Q
what does triose mean
A
3 Carbon atoms in the monosaccharide
20
Q
what does hexose mean
A
6 Carbon atoms in the monosaccharide
21
Q
what is those most common # of C in monosaccharides
A
hexose 6
22
Q
where does numbering begin in monosaccharides
A
the carbon closest to the carbonyl
23
Q
why is glucose called an aldohexose
A
it has double bond at c1 and 6 carbons
24
Q
how many chiral centers do all monosaccharides (except for dihydroxyacetone) have
A
at least 1
25
For N chiral centers, how mant possible steroisomers are there
2^N
26
what are epimers
isomers that differ in configuration at one ONE chiral carbon
27
what classified monosaccharides as D or L
based on the configuration of the chiral carbon most distant from the carbonyl group
28
what are enantiomers
mirror reflection stereoisomers
29
in fishcer projection, whcih side will the OH be on (starting from the C furthest from the carbonyl) for it to be a D isomer
OH on the right
30
in fishcer projection, whcih side will the OH be on (starting from the C furthest from the carbonyl) for it to be a L isomer
OH on the left
31
which carbon on glucose determines whether its D or L
C5
32
what happens if there is more than 2 chiral centers adjusted in a molecule (so if you compare the OG molecule to the one with 2 changed chiral centers)
it is not an epimer or an enantiomer - its just a stereoisomer
33
how many epimers of D-glucose are also D monosaccharides
3 (you can change C2 C3 and C4)
34
with an aldose and ketose with the same amount of carbons, how do they compare with the amount of chiral centers
why
there is 1 less chiral center in the ketoses compared to the aldose equivalents (because the ketone at C2 removes one stereocenter)
35
what is a pyranose
6 membered ring
36
what is a furanose
5 membered ring
37
what is the carbonyl converted to when it becomes a cyclic structure
either hemiacetal (aldose) or hemiketal (ketose)
38
how do monosaccharides adopt cyclic conformation (what is the reaction)
intramolecular rxn, C5 OH groups acts as a nucleophile towards the C1 or C2 carbonyl
39
what is an anomeric carbon
the carbon that is now in chiral form due to the monosaccharide becoming cyclic (so either C1 in aldoses or C2 in ketoses)
40
what is the structure of a hemiacetal
when an alcohol and ether are attached to the same carbon
41
what is the structure of a hemiketal
alcohol and ether attached to the same carbon with 2 other carbons attached
42
what is the difference with a hemiketal and a hemiacetal
hemiacetal will have an extra H group, in hemiketal that H group would be a C
43
how does the cyclic and linear form compare with the amount of chiral centers
the cyclic has 1 more chiral center
44
what 2 molecules react to create the hemiacetal
C-5 hydroxyl reacts with C-1 aldehyde
45
which is the anomeric carbon in glucose
C1
46
which is the new chiral carbon in glucose
C1
47
when do you have alpha glucose
then the OH of C1 is on the opposite side of the ring relative to C6 (OH down), C6 up)
48
when do you have beta glucose
then the OH of C1 is on the same side of the ring relative to C6 (OH up, C6 up)
49
how can you interconvert alpha and beta forms
by reforming the hemiacetal (mutarotation)
50
how do you know if glucose in ring structure is L
C6 will be down
51
how do you know if glucose in ring structure is D
C6 will be up
52
where is C6 and OH in alpha-D-glucopyranose
```
C6 up (D)
OH down (alpha)
```
53
where is C6 and OH in beta-D-glucopyranose
```
C6 up (D)
OH up (beta, same side)
```
54
where is C6 and OH in alpha-L-glucopyranose
```
C6 down (L)
OH up (alpha means opposite site)
```
55
which OH carbon determines whether its alpha or beta
the OH on C1
56
where is C6 and OH in beta-L-glucopyranose
```
C6 down (L)
OH down (beta, same side)
```
57
which form of glucopyranose has C6 up OH down
alpha-D-glucopyranose
58
which form of glucopyranose has C6 down OH down
beta-L-glucopyranose
59
which form of glucopyranose has C6 up OH up
beta-D-glucopyranose
60
which form of glucopyranose has C6 down OH up
alpha-L-glucopyranose
61
what % is usually beta in glucopyranose (how much is in that form compared to to other forms)
66%
62
what % is usually alpha in glucopyranose (how much is in that form compared to to other forms)
33%
63
what % is usually linear in glucopyranose (how much is in that form compared to to other forms)
less than 1%
64
is interconversion between alpha and beta spontaneous
| explain (2 things)
yes, it will slowly come to equilibrium with the linear form as an intermediate
65
what is the name of the cyclic 5 carbon monosaccharide
furanose
66
what is the name of the cyclic 6 carbon monosaccharide
pyranose
67
which cyclic form can aldoses with 5 or more carbons form
pyranose or furanose
68
is pyranose or furanose more stable and why
pyranose because its larger
69
if OH is down on the Haworth projection, will it be on the right or left side in a fischer projection
right
70
whats the best 2 step process to determine whether its beta/alpha and L/D
1- look at C6 (down=L up=D)
| 2-look at C1 (opposite to C6=alpha same as C6=beta)
71
if OH is up on the Haworth projection, will it be on the right or left side in a fischer projection
left
72
if found on the left of the fischer diagram, will the OH be on the top of bottom in Hayworth
top
73
if found on the right of the fischer diagram, will the OH be on the top of bottom in Hayworth
down
74
what is so special about the bonding patten in anomeric carbons
they are the only ones that are attached to 2 oxygens (OH and ether)
75
is bond breaking required to go between chair conformations of pyranose rings
no
76
is it most stable to have equatorial or axial position in the chair
equitorial
77
thinking about the cyclohexane chair model, why is the beta form more common than alpha
because alpha requires you to have some the OH and C6 pointing in opposite directions, so there will be at least 1 thing in the axial form (but beta can have all in equitorial which is more stable)
78
where does the ether come from in glucopyranose
the OH from C5
79
what attacks which carbon to make a furanose ring
OH from C5 attacks carbonyl from C2
80
what attacks which carbon to make a pyranose ring
OH from C5 attacks carbonyl from C1
81
what are aldonic acids
oxidation at C1
82
how do you name aldonic acids
"-onic acid"
83
what are uronic acids
oxidation of primary alcohol
84
how do you name uronic acids
"-uronic acid"
85
what are 2 types of oxidized sugars
aldonic and uronic acids
86
what is a type of reduced sugar
alditol
87
what is an alditol
reduction of carbonyl to alcohol
88
how do you name alditols
"-itol"
89
what are deoxy sugars
removal of OH from monosaccharide
90
what is an amino sugar
replacement of OH (usually at C2) in monosaccharide with NH2 / NH3+
91
how do you name aino sugars
"-amine"
92
how and where do amino sugars differ than a normal sugar
OH is replaced with NH2 NH3+ (usually at C2)
93
what often happens to the amino group in amino sugars
it is acetylated
94
is there a charge on acetylated amino sugars
no
95
is there a charge on amino sugars
yes
