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Biochemistry 2 > Lab 11 - Determination of Vitamins > Flashcards

Lab 11 - Determination of Vitamins Flashcards

1
Q

In general, what are vitamins?

A

Accessory food factors - necessary

Needed in small amount, but cannot be produced in body.

Vitamins are used in the body usually as COENZYMES

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2
Q

The quantitative determination of vitamins has two main routs?

A
  1. To make the vitamin visible + measure the absorbance by photometry
  2. Measure effects of vitamin in biological system.
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3
Q

What is a Precursor of Vitamin A?

A

Beta carotene

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4
Q

Where is carotinase found?

A

In the intestinal wall of domestic animals

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5
Q

Where is Beta-caroten absorbed?

A

Beta-caroten is absorbed through the INTESTINAL WALL.

Then gets into the blood circulation

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6
Q

Where can the Beta-caroten be detected?

A

In the blood plasma

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7
Q

What is the absorbed beta-caroten converted into?

A

Its converted into Vitamin A

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8
Q

Where is the absorbed beta-carroten converted into Vitamin A?

A

In the LIVER and MAMMARY GLAND

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9
Q

What are beta-caroten soluble in?

A

Beta-caroten is FAT-soluble

- Thats why we need organic compounds to detect it.

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10
Q

How do you measure beta-carroten?

A

With instruments:
- PETROLETHER in extract = yellow, and INTENSITY can be measured SPECTROPHOTOMETER
Without:
Concentrations

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11
Q 
At which value can you say that the beta-caroten concentration is:
- Weak
- Medium
- Good
When the supply is?.....
A
  • Weak: <2 micomol/L
  • Medium: 2-5,6 micromol/L
  • Good: 5,6-9,3 micromol/L
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12
Q

When determine B-carrotene in BP, name 2 important materials needed (substances)?

A

Ethanol

Petrolether

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13
Q

Where is VIT A absorbed?

A

From the intestine –> Gets into the LIVER by blood in form of RETINYLESTER

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14
Q

Where can VIT A be stored?

A

In LIVER

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15
Q

What is VIT A level proportional to?

A

VIT A level is proportional to the vitamin supply of the animal

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16
Q

Vitamin A from the liver can be determined by?….

A

Carr Price´s Reaction

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17
Q

What is the principle of the Carr Price´s Reaction?

A

Vit A dissolves in chloroform
- Blue color with antimony trichloride (SbCl3)

The reaction consist of the insoluble compound SbCl3 + Water
–> Not suitable -> Water has to be drawn off

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18
Q

Name 4 importaint substances when determining VIT A in liver?

A
  • Na2SO4 (in riboflavin detection Na2S2O4)
  • Chloroform
  • Acetic acid anhydride
  • Chloroform saturated w/ SbCl3
    (light+water sensitive)
19
Q

When observating the determination of VIT a in the liver, what are the colors?

A

Blue –> Purple

20
Q

What kind of vitamin is THIAMINE?

21
Q

When determining THIAMINE (B1), what is the general about THIAMINE?

A 
- It expresses its biological effect in the organism as:
Thiamine pyrophosphate (TPP)
  • It is the coenzyme of the oxidative decarboxylation of alpha-keto-acids
22
Q

What are the most important reaction of oxidative decarboxylation of alpha-keto-acids (THIAMINE, B1)

A

Pyruvate –> Acetyl CoA

alpha-ketoglutarate—> Succinyl CoA

23
Q

What is the principle of detection of THIAMINE (b1)?

A
  • In alkaline mileu = Thiamine transferred into THIOCHROME

- This compound shows BLUE fluorescence in UV-Light!

24
Q

When determining THIAMINE (B1), which 5 compound is really important?

A
  • Vitamin B1 injection
  • NaOH
  • K3(Fe(CN)6)
  • I-butanol
  • UV-LAMP
25
Q

What is general about Riboflavin?

A
  • Vitamin B2
  • Prosthetic group of several enzymes in the class of OXIDO-REDUCTASES is produced from RIBOFLAVIN
  • Ribaflavin are able to transport oxygen.
26
Q

What is produced when the coenzyme can pass the hydrogen directly to the oxygen of the air?

A

Hydrogen perixide is produced
or
An enzyme of the respiratory chain:
- Coenzyme Q

27
Q

The oxidized form of riboflavin shows which color?

A

GREEN flouressence in UV light

Redused form= Nothing happens

28
Q

When determining Riboflavin (B2), name 3 important materials(substances) needed.

A

Neovit B complex injection
Na2SO2O4 (almost as VIT a:Na2SO4)
UV lamp
(black background)

29
Q

What is special about determination of Ascorbic Acid as a vitamin?

A

For animal organism:
Vit C cannot be classified as strictly in the groups of vitamins
- Because every species can synthesize it

30
Q

What is the precursor of Ascorbic Acid (Vit C) syntheses?

A

The precursor of its synthesis is GLUCOSE

31
Q

Determination of Ascorbic Ac (VIT C)?

What is the determination based on?

A

The determination is based on the reducing properties of Ascorbic acid
(similar to Glucose)

32
Q

Where is the ascorbic acid excreted?

A

In form of dehydro-acerbic acid in the URINE

33
Q

When does domestic animals require Vitamin C supplement?

A

If they are affected my continuously STRESS

poultry

34
Q

The ascorbic reduction potential can be examined with which reaction?

A

Fehlings treaction

35
Q

Name some important materials needed when examining the reduction potential?

A

Ascorbic acid
Fehlings regent I
Fehlings regent II
Hydrogen peroxide

36
Q

The ascorbic reduction potential is examined by redox reaction, but how?

A 
Dehydro acerbic acid (OX) = Green/blue
Ascorbic Acid (RED) = Yellow = POSITIVE fehlingsreaction

Ascorb ac is able to donate 2H
Dehydro-ascorbic acid is able to accept 2H

37
Q

When examining ascorbic reduction potential with 2,6 dichlorphenol-indophenol - What is is?

A

2,6 dichlorphenol-indophenol = REDOX and a acid-base indicator at the same time.

REDOX indicator= Colourfull when OX
ACID-BASE indicator:
Alkaline + Neutral = Blue
Acidic mileu = RED

Colour depends on PH

38
Q

Name 4 importaint materials when examining the ascorbic reduction potential with 2,6 dichlorphenol-indophenol ?

A

Ascorbic Acid
2,6 dichlorphenol-indophenol
Na2Co3 solution
Acetic acid

39
Q

The dehydro-ascorbic acid can be detected from where, and by using what?

A

From Urin

By using: 2,4-dinitro-phenylhydrazine

40
Q

What is the principle of the reaction when using 2,4-dinitro-phenylhydrazine to detect the dehydro-ascorbic acid?

A

The excess of 2,4-dinitro-phenylhydrazine will react with the carbon molecules in position 1 and 2 of the dehydro-ascorbic acid.

41
Q

The excess of 2,4-dinitro-phenylhydrazine will react with the carbon molecules in position 1 and 2 of the dehydro-ascorbic acid.

What is produced?

A

Ascorbic acid and
Osazone
is produced

42
Q

When Ascorbic acid and Osazone
is produced, in which substance is it soluble in?
And what will happen if you put the products in this substance?

A

Soluble in Sulphuric acid

ORANGE-RED color

43
Q

The dehydro-ascorbic acid is detected from where? And by what?

A

From urin

Using: 2,4-dinitro-phenylhydrazine

44
Q

When detecting dehydro-ascorbic acid, what materials are essential?

A 
Urine
Trichloracetic acid
2,4-dinitro-phenylhydrazine
Thiocarbamid
Sulphuric acid
Active carbon powder

Biochemistry 2 (7 decks)

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