Carbohydrates lab Flashcards

1
Q

Starch is isolated from plant sources via ____ since starch is slightly soluble in H2O

A

selective dissolution

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2
Q

Starch is a good example of a ____.

homoglycan or heteroglycan

A

homoglycan

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3
Q

What are the two polysaccharides that build up starch?

A

Amylose & Amylopectin

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4
Q

Among the two polysaccharides that build up starch, which is linear (unbranched)?

A

Amylose

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5
Q

The linear polysaccharide that builds up starch is connected by ____ glycosidic bonds

A

α-1,4-glycosidic bonds

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6
Q

Among the two polysaccharides that build up starch, which is branched?

A

Amylopectin

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7
Q

Amylopectin, similar to the linear polysaccharide that builds up starch via α-1,4-glycosidic bonds, the branching is linked via ____ glycosidic bonds

A

α-1,6-glycosidic bonds

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8
Q

What saccharide will you isolate from liver?

A

glycogen

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9
Q

what isolation principle ruptures the membranes of the liver so as to free glycogen?

A

homogenization

iirc, via boiling ito

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10
Q

what reagent is used to remove the proteins of the liver via precipitation so as to free glycogen?

A

10% TCA

trichloroacetic acid

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11
Q

what reagent is used to precipitate glycogen from the homogenized sample wherein it occurs via the losing of the H2O shell surrounding the glycogen?

A

95%EtOH

ethanol

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12
Q

what reagent is used to facilitate the precipitation of glycogen using the principles of salting-out?

A

NaCl

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13
Q

the human liver composes how many percent of the body’s total mass?

A

10%

~10%

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14
Q

what polysaccharide is the energy reserve of animals that provides sugar for 24-36 hours?

A

glycogen

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15
Q

Identify the test based on principle

strong acid to dehydrate monosaccharide to produce furfural or hydroxymethylfurfural. Intermediate furfural derivatives will condense with α-naphthol

A

Molisch’s test

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16
Q

Identify the test based on principle

formation of complex (complexation) with iodine

A

iodine test

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17
Q

Identify the test based on principle

Cu2+ reduction; cupric oxide to cuprous oxide in a basic (sodium citrate) medium

CuO –> Cu2O

A

benedict’s test

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18
Q

Identify the test based on principle

Cu2+ reduction; cupric oxide to cuprous oxide in an acidic (acetic acid) medium

CuO –> Cu2O

A

barfoed’s test

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19
Q

Identify the test based on principle

Strong acid to dehydrate monosaccharide to produce furfural or hydroxymethylfurfural then condensation with resorcinol

A

seliwanoff’s test

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20
Q

Identify the test based on principle

Strong acid to dehydrate monosaccharide to produce furfural or hydroxymethylfurfural then condensation with orcinol

A

bial’s orcinol test

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21
Q

Identify the test based on principle

formyl functional group/prim alcohol oxidation to carboxylic acid by nitric acid

A

mucic acid test

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22
Q

Identify the test based on principle

formyl group/2ndary alcohol oxidation to carboxylic acid/ketone, respectively, by phenylhydrazine

A

phenylhydrazine/osazone test

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23
Q

positive result of molisch’s test

A

purple ring at interphase

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24
Q

positive result of iodine test

A
  • blue-black sol’n for starch
  • red-pink sol’n for glycogen
25
Q

positive result of barfoed’s test

A

brick-red ppt

26
Q

positive result of benedict’s test

A

brick-red ppt

27
Q

positive result of seliwanoff’s test

A

cherry-red solution

28
Q

positive result of bial’s orcinol test

A

blue-green solution

29
Q

positive result of mucic acid test

A

broken glasslike/rhombic crystals

under a microscope

30
Q

positive result of phenylhydrazone/osazone test

A

yellow orange crystals

31
Q

Identify the test based on reagents

H2SO4, EtOH and α-naphthol

A

Molisch’s test

32
Q

Identify the test based on reagents

Iodine solution

A

Iodine test

duh

33
Q

Identify the test based on reagents

CuSO4, Na2CO3, Na3C6H5O7

A

Benedict’s test

34
Q

Identify the test based on reagents

Cu(CH3COO)2, acetic acid

A

Barfoed’s test

35
Q

Identify the test based on reagents

HCl, resorcinol

A

Seliwanoff’s test

36
Q

Identify the test based on reagents

HCl, FeCl3, and orcinol

A

Bial’s orcinol test

37
Q

Identify the test based on reagents

concentrated HNO3

A

mucic acid test

38
Q

Identify the test based on reagents

phenylhydrazine

A

phenylhydrazone/osazone test

39
Q

Identify the qualitative tests based on what they’re testing for

reducing sugars

A
  • Barfoed’s test
  • Benedict’s test
40
Q

Identify the qualitative tests based on what they’re testing for

polysaccharide presence

A
  • Molisch’s test
  • Iodine test
41
Q

Identify the qualitative tests based on what they’re testing for

ketohexoses

or ketoses

A

Seliwanoff’s test

42
Q

Identify the qualitative tests based on what they’re testing for

pentoses

A

Bial’s orcinol test

43
Q

Identify the qualitative tests based on what they’re testing for

galactose and lactose

A

mucic acid test

44
Q

Identify the qualitative tests based on what they’re testing for

saccharides with free carbonyl group at C1 or C2

A

Phenylhydrazone/Osazone test

45
Q

What is the solvent system used in tlc of carbs?

A

Acetonitrile:Water (85:15)

46
Q

What is the visualizing agent used to view spots in the chromatoplate?

A

p-anisaldehyde

47
Q

the more -OH grps there are, the ____ polar the sugar is; therefore, it will be more adsorbed by the silica gel.

A

more polar

48
Q

In quantitative analysis, the amount of carbohydrates present in a given sample can be measured by ____

A

Nelson’s method

49
Q

What method in quantitative analysis of carbs is based on the capacity of the free reducing groups of sugars in a carbohydrate sample to reduce Cu2+ in an alkaline solution?

A

Nelson’s method

50
Q

The Colorimetry of Absorbance is based on the intensity of the product of arsenomolybdate and the copper oxide solution and is measured at ____nm.

A

480

51
Q

sodium potassium tartrate is also known as?

A

rochelle salt

52
Q

In Nelson’s method, what reagent serves as the oxidation agent?

A

CuSO4

53
Q

What reagent prevents the precipitation of Cu(OH)2?

A

Sodium Potassium Tartrate

Rochelle salt

54
Q

In Nelson’s method, what reagent is added to dissolve Cu2O and is converted to molybdenum blue?

A

Arsenomolybdate reagent

55
Q

The more intense the blue coloration is (molybdenum blue), the greater the amt of Cu2+, and the ____ the amt of sugar there is.

greater or lesser

A

greater

56
Q

Acid hydrolysis is a complete hydrolysis, therefore it yields what products?

A

monosaccharides

glu fru galac etc

57
Q

Enzymatic hydrolysis is what type of hydrolysis?

complete or incomplete?

A

incomplete

coz it breaks specific bonds onli

yields a mixture of glu, mal, & other hydrolysates (amylase is an example)

58
Q

nice to remember:

why is basic hydrolysis not used in the exp?

A

bcoz aldo & keto grps are sensitive to strong base attacks, leading to its epimerization (aldose-ketose interconvertion)

syempre magfafalse ibang tests like say for example fructose won’t be a ketose na or smth