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Biomolecules > Qualitative Reaction of Proteins (Lab) > Flashcards

Qualitative Reaction of Proteins (Lab) Flashcards

1
Q

are macromolecules that are made from one or more chains of polypeptides

A

proteins

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2
Q

are linear polymers making up proteins

A

polypeptides

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3
Q

Polypeptides are linear polymers made up from smaller molecules called

A

amino acids

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4
Q

Polypeptides
are formed when amino acids are joined together via typical ___bonds that forms between
amino group of one amino acid and carboxyl group

A

peptide

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5
Q

Proteins are the structural building blocks of almost all major cellular components and
structures, such as

A

enzymes
ribosomes
cytoskeleton
centrosomes
proteasomes

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6
Q

There are more than _
different amino acids found in biological organisms

A

20

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7
Q

Amino acids have characteristic chemical and
structural features

A

amino group (-NH2)
carboxyl group (-COOH)

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8
Q

They have an amino group (-NH2) plus a carboxyl group (-COOH) as functional
groups which are covalently attached to the

A

first (a) carbon atom

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9
Q

Proteins can be visualized and be tested with the help of series of unique dyes, such as

A

biuret reagent
coomasie blue (lowry reagent)

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10
Q

Amino acids can be visualized and be tested for with the help of a
chemical reagent called

A

ninhydrin

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11
Q

However, a simple and relatively quick qualitative test for the
presence of amino acids in solution is the

A

Whatman filter paper spotting test

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12
Q

is performed to analyze proteins in solid samples

A

ninhydrin test

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13
Q

samples for protein qualitative analysis

A

egg albumin
diluted honey
potato starch
milk
egg yolk
glucose
amino acid
meat (pork,fish)
egg white
cooked rich

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14
Q

biuret reagent

A

sodium hydroxide
copper (II) sulfate
potassium sodium tartate

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15
Q

very poisonous

A

ninhydrin

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16
Q

inhaling the fumes of ___ is not advisable

A

ninhydrin

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17
Q

amino acid common structure (3)

A

amino group
carboxyl group
variable side chain (R group)

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18
Q

gives the amino acid its unique chemical properties.

A

R group

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19
Q

The specific sequence of amino acids in a protein is the

A

primary structure

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20
Q

This structure may be recited by naming each amino acid beginning on the _-terminus.

A

N terminus

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21
Q

Proteins twist, turn, and fold into complex three dimensional shapes.

what structure

A

tertiary structure

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22
Q

These twists and turns are possible because there is ____ of the bonds around the α-carbon of each amino acid.

A

free rotation

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23
Q

sequence of amino acids in a polypaptide chain, similar to the sequence of letters that spell out a specific word

what structure

A

primary structure

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24
Q

the corkscrew like twists or pleated folds formed by hydrogen bonds between amino acids in the polypeptide chain

what structure

A

secondary structure

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25
Q

the complex three dimensional shape formed by multiple twists and bends in the polypeptide chain, based on the side chains interactions with each other and the aqueous solvent

A

tertiary structure

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26
Q

two or more polypeptide chians bonded together

what structure

A

quaternary structure

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27
Q

positive test for biuret indicates

A

protein is present

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28
Q

biuret positive test

A

purple

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29
Q

In the presence of alpha (α)-amino acids what is observed in ninhydrin test

A

blue to blue violet color

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30
Q

ninhydrin reagent

A

ninhydrin in 10ml of either ethanol or acetone.

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31
Q

deep purple positive for ninhydrin means

A

For ammonia, primary/secondary amines, and amino acids

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32
Q

yellow positive for ninhydrin means

A

hydroxyproline and proline

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33
Q

brown positive for ninhydrin means

A

asparagine

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34
Q

organic macromolecules containing C,H,O,N

A

proteins

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35
Q

examples of proteins

A

enzymes
body tissues
many immune system cells

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36
Q

monomers of proteins

A

amino acid

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37
Q

amino acids joint to form small protein polymers called

A

peptides

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38
Q

long protein polymers are called

A

polypeptides

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39
Q

its characteristic that is critical to function

A

folded

40
Q

sources of protein

A

beans
grams
lentils
peas
soya beans
eggs
paneer
fish
meat
milk

41
Q

are macromolecules that are made from one or more chains of polypeptides

A

proteins

42
Q

linear polymers made up from smaller molecules

A

polypeptides

43
Q

polypeptides are formed when amino acids are joined together via typical ___ bonds

A

peptide bonds

44
Q

amino acid common core structure

A

amino group (-NH2)
carboxyl group (COOH)
R group

45
Q

functional group which are covalently attached to the first (a) carbon atom

A

carboxyl group

46
Q

part that gives the amino acid its unique chemical properties

A

R group

47
Q

basic functional group

A

amino group

48
Q

side chains;
wild card structure

A

R groups

49
Q

acidic functional group

A

carbonyl group

50
Q

polar in nature

A

carbonyl group

51
Q

essential amino acids

A

Phenylalanine
Valine
Tryptophan

Threonine
Isoleucine
Methionine

Histidine
Leucine
Lysine

52
Q

conditionally essential amino acid

A

arginine
cysteine
proline
tyrosine
glutamine
glycine

53
Q

nonessential amino acids

A

alanine
asparagine
aspartic acid
glutamic acid
serine

54
Q

arrangement of amino acids

what structure

A

primary structure

55
Q

protein structure levels that has hydrogen bonds

A

secondary structure

56
Q

protein structure levels that has alpha helix and beta-pleated sheet

A

secondary structure

57
Q

protein structure levels that has R group interactions

A

tertiary structure

58
Q

proteins with more than 1 polypeptide subunit

A

quaternary structure

59
Q

specific sequence of amino acids in a protein is the

A

primary structure

60
Q

which starting terminus a protein can be recited by naming each amino acid

A

N-terminus

61
Q

twist, turn, and fold into complex three dimensional shapes

A

proteins

62
Q

why is twists and turns possible in protein

A

free-rotation of the bonds around the a-carbon of each amino acid

63
Q

which sample is used for biuret test

A

egg albumin
diluted honey
potato
starch
milk
egg yolk
glucose
amino acid

64
Q

filter paper test samplpe

A

amino acids

65
Q

ninhydrin test sample

A

meat (pork,fish)
egg white
cooked rice

66
Q

biuret test procedures

A

pipette 2ml of the solutions (distilled water, egg albumin, diluted honey, potato starch, glucose solution, egg yolk, amino acid)

add one dropperful of Biuret reagent into each of the test tubes and gently mix

place the tubes back into the rack and incubate contents for about 2 minutes at your work bench

67
Q

specific for peptide bond

A

biuret test

68
Q

substances containing not less than two peptide linkages give this test

A

biuret test

69
Q

principle of biuret test

A

when proteins and peptides treated with an alkaline solution of dilute copper sulfate, a violet color is formed

70
Q

what characteristic of biuret test result is proportional to the amount of proteins present

A

color density

71
Q

biuret agent is what kind of solution

A

alkaline copper sulfate

72
Q

chemical reation to detect existence of amino acids

A

ninhydrin reaction

73
Q

used for liquid samples

A

filter paper test

74
Q

indicate that there is an amino acid in the spot solution

A

purple stians

75
Q

gives a yellow colour because it is a secondary amine

A

proline

76
Q

how many sample is used for ninhydrin test

A

2 mg

77
Q

how much to boil test mixture in ninhydrin test

A

15-20 seconds

78
Q

what is observed when there is alpha amino acid in ninhydrin test

A

blue-violet color

79
Q

result of distilled water in biuret test

A

negative result

80
Q

biuret test result of egg albumin

A

violet/purple color (+)

81
Q

biuret test result of diluted honey

A

yellow (-)

82
Q

biuret test result of potato starch

A

negative (-)

83
Q

biuret test result of glucose solution

A

-

84
Q

biuret test result of egg yolk

A

positive (+)

85
Q

result of amino acids in biuret test

Tyrosine
Proline
Tryptophan
Asparagine

A

All positive but proline will be yellow in color instead of purple

86
Q

ninhydrin test result of distilled water

A

negative

87
Q

ninhydrin test result of asparagine

A

positive (blue or purple color)

88
Q

ninhydrin test result of proline

A

positive (yellow color)

89
Q

ninhydrin test result of tryptophan

A

purple (+)

90
Q

ninhydrin test result of tyrosine

A

purple (+)

91
Q

ninhydrin test result of pork meat

A

positive (+)

92
Q

ninhydrin test result of salmon

A

positive (+)

93
Q

ninhydrin test result of egg white

A

(+)

94
Q

ninhydrin test result of cooked rice

A

(+)

95
Q
  1. In the test for proteins, which structure in the proteins does the Biuret reagent reacts with?
A

The Biuret reagent reacts with the peptide bonds in proteins. Peptide bonds are the chemical links between amino acids that form the primary structure of a protein. When the Biuret reagent, which contains copper sulfate, interacts with these peptide bonds, it forms a violet-colored complex. This color change indicates the presence of proteins.

96
Q
  1. Which amino acid solutions resulted positive with the Ninhydrin Test? Explain.
A

all but proline will be yellow since it has a secondary amine group

Biomolecules (19 decks)

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