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BIO 024: Biochemistry > Laboratory: Carbohydrates > Flashcards

Laboratory: Carbohydrates Flashcards

(71 cards)

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1
Q

General Tests for Carbohydrates:

The reaction is based on the fact that concentrated H2SO4 (dehydrating agent) catalyses the dehydration of sugars to form furfural (from pentoses) or hydroxymethyl furfural (from hexoses).

A

Molisch Test

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2
Q

T.R. of Molisch Test

A

purple or violet coloured ring at the junction

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3
Q

General Tests for Carbohydrates:
Its principle is same as that for molisch’s test except that the furfurals and hydroxy -methyl furfurals give condensation products with anthrone that are bluish green in colour.

A

Anthrone’s Test

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4
Q

T.R. of Anthrone’s Test

A

Bluish-green color

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5
Q

General Tests for Carbohydrates:
is used to test for the presence of starch.

A

Iodine Test

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6
Q

Iodine Test: Starch turns into an intense “_______” colour upon addition of aqueous solutions of the triiodide anion, due to the formation of an intermolecular charge-transfer complex.

A

“blue-black”

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7
Q

Iodine Test: In the absence of starch, the ______ colour of the aqueous solution remains.

A

brown

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8
Q

Specific tests for carbohydrates:

This test is a timed colour reaction specific for ketohexoses.

A

SELIWANOFF’S TESTS

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9
Q

Seliwanoff’s Test is named after ______.

A

Theodor Seliwanoff

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10
Q

T.R. for Seliwanoff’s Test

A

red coloured complex

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11
Q

Specific tests for carbohydrates:

This test is specific for pentoses and the compounds containing pentoses and thus useful for the determination of pentose sugars

A

BIAL’S ORCINOL

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12
Q

T.R. for Bial’s Orcinol

A

blue green coloured complex

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13
Q

Specific tests for carbohydrates:

This test is highly specific for galactose which is either independently present in solutions or obtained by the hydrolysis of lactose

A

MUCIC ACID TEST

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14
Q

Specific tests for carbohydrates:

a.k.a PHENYLHYDRAZINE TEST OR KOWARSKY TEST

A

OSAZONE TEST

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15
Q

Specific tests for carbohydrates:

An organic compound phenylhydrazine reacts with carbonyl carbon (or more specifically C1 and C2) of sugar to form the compound called osazones or phenylhydrazone.

A

OSAZONE TEST

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16
Q

Specific tests for carbohydrates:

A test to detect reducing and non-reducing sugar

A

FEHLING’S TEST

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17
Q

Specific tests for carbohydrates:

This test can be used to screen for glucose in urine, thus detecting diabetes.

A

FEHLING’S TEST

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18
Q

T.R. for Fehling’s Test

A

brick-red precipitate of Cu2O.

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19
Q

Specific tests for carbohydrates:

This test is performed to distinguish between a reducing mono- and disaccharide.

A

BARFOED’S TEST

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20
Q

Specific tests for carbohydrates:

modified the Fehling’s solution to produce an improved single reagent which quite stable.

A

BENEDICT’S TEST

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21
Q

Benedict’s Test: Blue colored solution

A

No significant change

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22
Q

Benedict’s Test: Green/Yellow precipitation

A

Traces of reducing sugar

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23
Q

Benedict’s Test: Orange color

A

Moderate

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24
Q

Benedict’s Test: Brick-red precipitation

A

Large amount of reducing sugar

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25
Other tests for carbohydrates: Test for galactose is also based on the formation of similar intermediate furfurals which condenses with phloroglucinol to form a red colored compound.
Tollen’s phloroglucinol test
26
Other tests for carbohydrates: The production of violet color indicates the presence of pentose.
Tauber’s benzidine Test
27
Other tests for carbohydrates: for polysaccharides; This test is performed to distinguish polysaccharides from mono- and disaccharides
Iodine test
28
It is the Principal storage form of carbohydrates in the mammalian body
Glycogen
29
A decrease in the glucose level below _________ causes brain dysfunction which can lead to coma and death.
70 mg/dL (hypoglycemia)
30
It is not generally available to other tissues because muscles lack the enzyme glucose-6-phosphatase
Muscle glycogen
31
It provides a source of energy for muscle contraction and is a readily available source of glucose for glycolysis within the muscle itself.
Muscle glycogen
32
Glycogen is synthesized from glucose by the pathway of ________, which occurs mainly in liver and muscle.
glycogenesis
33
catalyzes formation of glycosidic bonds between C1 of the activated glucose of UDPGlc and C4 of a terminal glucose residue at the non-reducing end of glycogen, liberating uridine diphosphate (UDP)
Glycogen synthase
34
can only extend existing chain of glycogen.
Glycogen synthase
35
a.k.a. glycogen primer
Glycogenin
36
must be present to initiate glycogen biosynthesis
Glycogenin
37
This integrates the regulation of glycogenolysis and glycogenesis by promoting the simultaneous activation of phosphorylase and inhibition of glycogen synthase.
Cyclic adenosine-3’,5’- monophosphate (cAMP)
38
______ acts reciprocally by inhibiting glycogenolysis and stimulating glycogenesis.
Insulin
39
Test for Keto Sugar
SELIWANOFF’S TESTS
40
What is the chelating agent for Benedict's Test?
Sodium Citrate
41
Based on oxidation: What is the T.R. of Glucose on Fehling's Test?
Brick red ppt
42
Based on oxidation: What is the T.R. of Fructose on Fehling's Test?
Brick red ppt
43
Based on oxidation: What is the T.R. of Galactose on Fehling's Test?
Brick red ppt
44
Based on oxidation: What is the T.R. of Maltose on Fehling's Test?
Brick red ppt
45
Based on oxidation: What is the T.R. of Sucrose on Fehling's Test?
Blue
46
Based on oxidation: What is the T.R. of Lactose on Fehling's Test?
Brick red ppt
47
Based on oxidation: What is the T.R. of Lactose on Benedict's Test?
Brick red ppt
48
Based on oxidation: What is the T.R. of Sucrose on Benedict's Test?
Blue
49
Based on oxidation: What is the T.R. of Maltose on Benedict's Test?
Brick red ppt
50
Based on oxidation: What is the T.R. of Galactose on Benedict's Test?
Brick red ppt
51
Based on oxidation: What is the T.R. of Fructose on Benedict's Test?
Brick red ppt
52
Based on oxidation: What is the T.R. of Glucose on Benedict's Test?
Brick red ppt
53
Based on oxidation: What is the T.R. of Glucose on Barfoed's Test?
Brick red ppt
54
Based on oxidation: What is the T.R. of Fructose on Barfoed's Test?
Brick red ppt
55
Based on oxidation: What is the T.R. of Galactose on Barfoed's Test?
Brick red ppt
56
Based on oxidation: What is the T.R. of Maltose on Barfoed's Test?
Brick red ppt
57
Based on oxidation: What is the T.R. of Sucrose on Barfoed's Test?
Blue
58
Based on oxidation: What is the T.R. of Lactose on Barfoed's Test?
Brick red ppt
59
On which reducing sugars shows Needle-like crystals T.R. for Mucic Acid Test?
Galactose and Lactose
60
General test for carbohydrates: What is the T.R. of Glycogen on Molish Test?
Violet ring at the junction
61
General test for carbohydrates: What is the T.R. of Starch on Molish Test?
Violet ring at the junction
62
General test for carbohydrates: What is the T.R. of Starch on Anthrone's Test?
Bluish green
63
General test for carbohydrates: What is the T.R. of Glycogen on Anthrone's Test?
Bluish green
64
General test for carbohydrates: What is the T.R. of Glycogen on the Iodine Test?
Yellow-brown (maltose)
65
General test for carbohydrates: What is the T.R. of Starch on the Iodine Test?
Blue-violet
66
BASED ON THE FURFURAL FORMATION AND ITS DERIVATIVES: What is the T.R. of Glucose on Seliwanoff's Test?
Yellow initially, red w/ prolonged heating for 15 mins
67
BASED ON THE FURFURAL FORMATION AND ITS DERIVATIVES: What is the T.R. of Xylose on Seliwanoff's Test?
Yellow initially, red w/ prolonged heating for 15 mins
68
BASED ON THE FURFURAL FORMATION AND ITS DERIVATIVES: What is the T.R. of Fructose on Seliwanoff's Test?
Cherry red or red (immediately dehydrated)
69
BASED ON THE FURFURAL FORMATION AND ITS DERIVATIVES: What is the T.R. of Fructose on Bial's Test?
Brown/dark red (-)
70
BASED ON THE FURFURAL FORMATION AND ITS DERIVATIVES: What is the T.R. of Xylose on Bial's Test?
Blue green (+)
71
nBASED ON THE FURFURAL FORMATION AND ITS DERIVATIVES: What is the T.R. of Glucose on Bial's Test?
Brown/dark red (-)

BIO 024: Biochemistry (16 decks)

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