LAB Exp 5. Carbs Flashcards
1
Q
Energy storage for polysaccharide implants
A
Starch
2
Q
Energy reserve for animals
A
Glycogen
3
Q
Glycogen provides sugar for ___ to ___ hours when fasting
A
24-36
4
Q
Carbohydrate with the same kind of monosaccharides
A
Homoglycan
5
Q
Source of starch
A
Cassava and potato
6
Q
Source of glycogen
A
Chicken liver
7
Q
Principle of starch isolation
A
Selective dissolution (starch is slightly soluble in H2O)
8
Q
Principle of glycogen isolation
A
Homogenization
9
Q
Process that ruptures the membranes
A
Homogenization
10
Q
2 physical methods of homogenization
A
Chemical
Enzymatic
11
Q
Role of 10% TCA in homogenization
A
Removes protein by precipitation
12
Q
Role of 95% EtOH in homogenization
A
Precipitates glycogen from the homogenized sample
13
Q
The loss of H2O shell surrounding glycogen molecule
A
Precipitation
14
Q
Reagent that facilitates precipitation of glycogen by salting-out
A
NaCl
15
Q
Starch is composed of two polysaccharides, namely
A
Amylose
Amylopectin
16
Q
The linear homoglycan of glucose connected by alpha 1-4 linkages
A
Amylose
17
Q
Which polysaccharide has linkages that are flexible, which allows chain to coil?
A
Amylose
18
Q
Gives the purple color of starch
A
I2 trapped in coil
19
Q
The branched homoglycan with approx. 1 in 25 glucose linked in both alpha 1-4 and alpha 1-6
A
Amylopectin
20
Q
Connected by alpha 1-4 glycosidic bonds
A
Linear chains
21
Q
alpha 1-6
A
Branched points
22
Q
Highly branched are considered in every __ in 10 glucose units
A
1
23
Q
Purpose of molisch’s test
A
Detects presence of carbohydrates
24
Q
Reagents for molisch’s test
A
H2SO4, EtOH, and alpha-naphthol
25
Positive result for molisch's test
Purple ring at interphase
26
Principle of molisch's test
Strong acid (H2SO4) to dehydrate monosaccharide to produce furfural or hydroxymethylfurfural
Intermediate furfural derivatives will condense with a-naphthol
27
Purpose of Iodine test
Detect the presence of polysaccharides
28
Reagents for iodine test
KI
29
Positive result for iodine test
Blue-black solution (starch-iodo complexation)
Red or pink solution (glycogen-iodo complex)
30
Principle of iodine test
Iodine slides into starch coil to give blue-black color
31
Purpose of benedict's test
Detect reducing sugars
32
Reagent for benedict's test
CuSO4, Na2CO3, Na3C6H5O7
33
Positive result for benedict's test
Brick-red ppt for all reducing saccharides (all monosaccharides)
34
Principle of benedict's test
Cu2+ oxidizing agent (oxidation)
Cupric ions are reduced to cuprous to form Cu2O ppt
Sodium citrate (basic) is used to keep Cu ions in the solution
35
Purpose of barfoed's test
Distinguishes reducing monosaccharides and disaccharides
36
Reagents for barfoed's test
Cu(CH3COO2), acetic acid
37
Positive result for barfoed's test
Brick-red ppt for all reducing monosaccharides
38
Principle of barfoed's test
Cu2+ oxidizing agent (oxidation)
Cupric ions are reduced to cuprous to form Cu2O ppt
39
Purpose of seliwanoff's test
Distinguish aldoses from ketoses (ketohexoses)
40
Reagent for seliwanoff's test
HCl, resorcinol
41
Positive result for seliwanoff's test
Cherry-red solution for ketohexoses
42
Principle of seliwanoff's test
Strong acid dehydrates the monosaccharide to produce furfural/hydromethylfurfural, then condensation with resorcinol
43
Purpose of bial's orcinol test
Specific for pentoses
44
Reagents for bial's orcinol test
HCl, FeCl3, orcinol
45
Positive result for bial's orcinol test
Blue-green solution for aldopentoses
46
Principle of bial's orcinol test
Strong acid dehydrates the monosaccharide to produce furfural/hydromethylfurfural, then condensation with orcinol
47
Purpose of mucic acid test
Specific for galactose and lactose
48
Reagent for mucic acid test
Conc HNO3
49
Positive result for mucic acid test
Broken glass-like or rhombic crystals
50
Principle of mucic acid test
HNO3 - strong oxidizing agent
Formyl will get oxidized into carboxylic acid
Primary alcohol will get oxidized to carboxylic acid
51
Purpose of osazone/phenylhydrazone test (all aldoses and ketoses)
For all sugars with free carbonyl group at C1/C2
52
Reagent for osazone/phenylhydrazone test
Phenylhydrazone
53
Positive result for osazone/phenylhydrazone test
Yellow-orange crystals (osazones)
D-glucosazone (for glucose)
No "sucrosazone"
54
Principle of osazone/phenylhydrazone test
Phenylhydrazine - strong oxidizing agent
Formyl functional group will get oxidized to carboxylic acid
Secondary alcohol will get oxidized to ketone
Product: phenylhydrazone + phenylhydrazine = osazone
55
Time of appearance of mannose from phenylhydrazone test
0.5 mins
56
Time of appearance of fructose from phenylhydrazone test
2 mins
57
Time of appearance of glucose from phenylhydrazone test
4-5 mins
58
Time of appearance of xylose from phenylhydrazone test
7 mins
59
Time of appearance of galactose from phenylhydrazone test
15-19 mins
60
Time of appearance of maltose from phenylhydrazone test
soluble in hot water
61
Time of appearance of lactose from phenylhydrazone test
soluble in hot water
62
Characteristics of mannose crystal in phenylhydrazone test
Needle-like/feathery
63
Characteristics of fructose crystal in phenylhydrazone test
Needle-like/feathery;
Broomstick
64
Characteristics of glucose crystal in phenylhydrazone test
Needle-like/feathery;
Broomstick
65
Characteristics of xylose crystal in phenylhydrazone test
Long, fine needle-like crystals
65
Characteristics of galactose crystal in phenylhydrazone test
Broad/flat crystals
66
Characteristics of maltose crystal in phenylhydrazone test
Broad, needle-like crystals;
Sunflower-shaped
67
Characteristics of lactose crystal in phenylhydrazone test
Fine needles, grouped in balls;
Hedgehog-shaped
68
A quantitative analysis that measures the amount of carbohydrates present in a given sample
Nelson's method
69
Nelson's method is based on capacity of the _____
Free reducing group of sugars to reduce Cu2+ in an alkaline solution
70
Principle of nelson's method
Sample is colorless; adding reagents oxidizes reducing sugars into aldonic acids
71
Reagents for Nelson's A
Rochelle salt
Sodium potassium tartrate
Na2CO3, NaHCO3, Na2, SO4
72
Purpose of CuSO4 in Nelson's method
Oxidizing agent
73
Purpose of Na2CO3 and NaHCO3 in Nelson's method
makes sugar more reactive
74
Purpose of NaKtartrate in Nelson's method
Prevents ppt of Cu(OH)2
75
T/F: Nelson's A & B are mixed before using NaKtartrate
F
76
Reagents for Nelson's B
CuSO4 x 5H2O
H2SO4
77
Reagents for Ammonium molybdate reagent
(NH4)2MoO4
H2SO4
Na2HASO4 x 7H2O
78
Purpose of ammonium molybdate reagent
Added to dissolve Cu2O
79
Principle of ammonium molybdate reagent
Converted into molybdenum blue; the intensity of blue coloration is dependent to the amount of Cu2O formed
80
A homoglycan is a mixture of 2 polysaccharides, namely _____ and _____
Amylose and amylopectin
81
Erythrose is an example of _____ (in terms of number of carbons)
Tetrose
82
Glyceraldehyde is an example of _____ (in terms of number of carbons)
Triose
83
Ribose is an example of _____ (in terms of number of carbons)
Pentose
84
Glucose and fructose are examples of _____ (in terms of number of carbons)
Hexose
85
Sedoheptulose is an example of _____ (in terms of number of carbons)
Heptose
86
Neuramic acid is an example of _____ (in terms of number of carbons)
Nonose
87
Hydrolyzable polymers of 2-6 monosaccharides
Oligosaccharides
88
89
Sucrose and lactose are examples of _____
Disaccharides
90
Hydrolyzable polymers of >6 monosaccharides
Polysaccharides
91
Polymer of a single type of monosaccharide
Homopolysaccharides
92
Glycogen and cellulose are examples of _____
Homopolysaccharides
93
Polymer of at least 2 types of monosaccharide
Heteropolysaccharides
94
Glucosaminoglycan is an example of _____
Heteropolysaccharide
95
Fumaric acid and maleic acid are examples of _____ (type of isomer)
Cis-trans isomers
96
2-Phosphoglycerate and 3-Phosphoglycerate are examples of _____ (type of isomers)
Positional isomers
97
