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Biochemistry > Biochemistry Lab - Quiz > Flashcards

Biochemistry Lab - Quiz Flashcards

1
Q

the fundamental chemical components of cells may be grouped into four basic categories

A

carbohydrates, proteins, lipids and nucleic acids

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2
Q

carbohydrates such as starch are detected by

A

mixing a sample with 2-4 drops of iodone or Lugol’s solution

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3
Q

if starch is present, the solution will turn from

A

yellow-brown color to dark purple

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4
Q

the color change in test for complex carbohydrates is due to a chemical reaction between

A

the large carbohydrate molecule and the iodine ions

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5
Q

carbohydrates such as starch are detected by mixing a sample with 2-4 drops of iodine or Lugol’s solution. The solution will turn from a yellow-brown color to dark purple if starch is present. The color change is due to a chemical reaction between the large carbohydrate molecule and the iodine ions. It is thought that the charged iodine ions are attracted to slight charges on the starch (polysaccharide) molecules, and this causes the color change.

A

Test for Complex Carbohydrates (Polysaccharides)

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6
Q

the presence of smaller carbohydrates like glucose can be determined by using

A

Benedict’s solution

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7
Q

has copper ions with a light blue color

A

Benedict’s solution

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8
Q

When Benedict’s solution is heated in the presence of sugars like glucose, the copper ions change and turn anywhere from

A

a light green to rusty orange-brown color

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9
Q

color if there is negative result in test for simple sugars (glucose)

A

blue

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10
Q

the presence of smaller carbohydrates like glucose can be determined by using Benedict’s solution. Benedict’s solution has copper ions with a light blue color. When Benedict’s solution is heated in the presence of sugars like glucose, the copper ions change and turn anywhere from a light green to rusty orange-brown color

A

Test for (Reducing) Simple Sugars (Monosaccharides)

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11
Q

The presence of proteins may be determined by mixing a solution with

A

Biuret test solution (or reagent)

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12
Q

is a mixture of copper ions, sodium hydroxide, and potassium sodium tartrate.

A

Biuret test

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13
Q

If proteins are present a chemical reaction occurs between the

A

copper ions and the protein molecules

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14
Q

The chemical reaction causes the Biuret test solution to turn from a _________________ if proteins are present

A

light blue to purple

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15
Q

what is the color if proteins are present/positive biuret test results

A

purple

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16
Q

what is the color if there is no presence of proteins/negative biuret test results

A

light blue

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17
Q

The presence of proteins may be determined by mixing a solution with. Biuret test is a mixture of copper ions, sodium hydroxide, and potassium sodium tartrate. If proteins are present a chemical reaction occurs between the copper ions and the protein molecules. The chemical reaction causes the Biuret test solution to turn from a light blue to purple if proteins are present

A

Test for Proteins

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18
Q

The presence of proteins can be determined using

A

Biuret Test

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19
Q

are fat-loving molecules that are colored.

A

Sudan Indicators

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20
Q

When testing a solution for lipids, there are two results one should be looking for:

A

a. Is there a separation of layers? (water & lipid)
b. Does the dye migrate toward one of the layers?

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21
Q

If the mixtures are all water soluble (no lipids present), then the Sudan IV will form

A

small micelles/droplets and disperse throughout the solution

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22
Q

A positive test result shows the

A

lipid layer sitting on top of the water layer, and the lipids layer will have a red-orange color

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23
Q

positive result in test for lipids has

A

2 layersand top layer is orange-red

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24
Q

negative result in test for lipids has

A

one layer and color is evenly distributed

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25
The presence of proteins can be determined using Sudan III indicator. Sudan Indicators are fat-loving molecules that are colored. When testing a solution for lipids, there are two results one should be looking for: a. Is there a separation of layers? (water & lipid) b. Does the dye migrate toward one of the layers? If the mixtures are all water soluble (no lipids present), then the Sudan IV will form small micelles/droplets and disperse throughout the solution. A positive test result shows the lipid layer sitting on top of the water layer, and the lipids layer will have a red-orange color
Test for Lipids
26
is used for determining the presence of nucleic acids
(Dische) Diphenylamine Test
27
The presence of DNA will turn a
clear blue solution
28
what color is positive results in test for nucleic acids
blue
29
negative results in test for nucleic acids
clear color
30
it is used to spin small (2 ml or less) liquid samples at high speeds
micro centrifuge, microfuge
31
Test for Biomolecules: Protein
Biuret Test
32
Test for Biomolecules: Carbohydrates
Molisch Test
33
Test for Biomolecules: Nucleic Acids: DNA
Dische Test
34
Test for Biomolecules: Nucleic Acids: RNA
Orcinol Test
35
are a class of naturally occurring organic compounds that undergo a variety of chemical reactions
Carbohydrates
36
is general test for carbohydrates, compunds that are dehydrated by concentrade H2SO4 to form furfural or hydroxymethyl furfural will reach with alpha napthtol to yield a purple condensation product.
Molisch's Test
37
Positive Molisch's Test:
purple color complex
38
Negative Molisch's test:
no purple color
39
is a specific test for reducing sugars or presence of free or potential aldehydes
Benedict's Test
40
identifies reducing sugars, which have free ketone or aldehyde functional groups
Benedict's test
41
Formation of a reddish precipitate within 3 minutes. Reducing sugars present.
Positive Benedict's Test
42
No color change (Remains blue). Reducing sugars absent
Negative Benedict's Test
43
No presence of reducing sugar
blue
44
has traces of reducing sugars
green/yellow
45
has moderate reducing sugars
oranged red
46
has large amount of reducing sugars
brick red
47
When Benedict's solution and simple carbohydrates are heated, the solution changes to
orange red/ brick red
48
is a test used to distinguish between monosaccharides and dosaccharides
Barfoed's Test
49
A positive reaction may be only a little dark red precipitate in the bottom of the test tube. If this appears within 2-3 minutes, it indicates a
monosaccharide
50
if a little dark precipitate does not appear or show after 10 minutes, ____________________ is indicated
disaccharide
51
development of brick red color precipitate within 3-5 minutes
Positive Barfoed's test
52
absence of red color
Negative Barfoed's Test
53
is a specific test for ketones
Seliwanoff's Test
54
This test is useful for distuinguishing fructose (a ketohexose) from glucose, mannose and galactose (aldohexose)
Seliwanoff's Test
55
(Seliwanoff's Test) ketohexose reacts with resorcinol to form a
bright red condensation product
56
(Seliwanoff's Test) aldohexose yields only a
pale pink colored product
57
is a test for pentoses and nucleotides that contain pentose sugars
Bial's Test
58
(Bial's Test) formation of blue color
Positive Bial's Test
59
formation of any other color in Bial's Test indicates
a negative test
60
(Bial's Test) Hydroxymethyl furfural (formed from hexoses) give a
yellow-brown condensation product
61
one of the most directed experimental approaches to identify invidual reaction steps is the study of
cell tissue dispersion
62
involves breaking of cell membrane and releasing its content
cell tissue dispersion
63
the dispersion can be prepared using
centrifugation
64
- contains DNA in its chromosomes - cell's control center
Nucleus
65
- combination of DNA and protein
chromatin
66
- serves as the site for the production of most cellular energy
mitochondrion
67
contains enzymes that convert the sugar glucose and other nutrients into ATP
mitochondrion
68
contain powerful enzymes capable of digesting organic material breaking down worn out cells
Lysosome
69
suicide bags
Lysosome
70
dismantle and recycle proteins, lipid, and other molecules
Lysosome
71
elongated membranous sac attached to the nuclear membrane
Endoplasmic Reticulum
72
thousands of ribosomes are attached to the membrane surface
Rough ER
73
site for enzyme reactions in steroid hormone production and inactivation, detoxifies poisonous chemicals, and manufactures lipids
Smooth ER
74
clear liquid
supernatant
75
5 drops of suspension 5 drops of 10% NaOH 0.5 of cupric sulfate (CuSO4)
Protein. Biuret Test
76
- 10 drops of suspension - 3 drops of Molisch reagent - 8 drops of concentrated sulfuric acid (H2SO4) - alphanapthtol
Carbohydrates. Molisch Test
77
2 ml of 1 M NaCl solution ethyl alcohol
isolation of nucleic acids
78
5 drops cell suspension 5 drops diphenylamine 6 drops concentrated sulfuric acid
DNA: Dische Test
79
7 drops orcinol reagent 7 drops cell suspension
RNA: Orcinol Test
80
the pH of the solution is "resistant" to small additions of either a strong acid or strong base
buffer solution
81
usually consist weak acid and its conjugate base
buffers
82
any weak acid
HA
83
conjugate base
A
84
can be made by mixing a soluble compund that contains the conjugate base with a solution of the acid such as sodium acetate with acetic acid or ammonia with ammonium chloride
buffer system
85
The Henderson-Hasselbalch governs most acid dissociation problems
pH = pKa + log [A-] / [HA]
86
are a solution that prevent a sudden increase or decrease in pH levels
Buffers
87
mixture of weak acid and conjugate base or a weak base and its conjugate acid
Buffers
88
refers to the maximum amount of either strong acid or strong base that can be added before a significant change in pH will occur.
Buffer capacity
89
a voltmeter with a high input impedance which meausre the voltage if an elctrode sensetive to the hydrogen ion concentration relative to another electrode which exhibits a constant voltage
pH meter
90
are a class of naturally occuring organic compounds that undergo a variety of chemical reactions
carbohydrates
91
are geminal-diether derivatives of aldehydes or ketones, formed by reaction with two equivalents of an alcohol or elimination of water
Acetals
92
is formed as an intermediate during the formation of an acetal
hemiacetal
93
the chemical tests employed to detect carbohydrates and to distinguish among them may be divided into two categories:
1. tests based on the production of furfural or substituted furfural 2. tests based on the reducing property of sugars
94
test when a sample is positive with glucose and sucrose and negative for galactose and lactose
Fermentation by Yeast
95
a test where starch gives a blue color with iodine while glycogen gives a reddish color with iodine
Iodine Test for Starch and Glycogen
96
a test where a furfural based by the action of HCl on pentose forms, a bright pink color with aniline acitate
aniline acetate test
97
1 mL portions 2 drops of Molisch reagent 0.6 concentrated H2SO4
Molisch's Test
98
1 mL portions 1.5 Benedict's solution
Benedict's Test
99
1 mL portions 1.5 Barfoed's reagent
Barfoed's Test
100
1 mL portions 1.5 mL Seliwanoff's reagent
Seliwanoff's Test
101
1 mL portions 1 mL Bial's reagent pentanol
Bial's Test
102
widely distributed in plant tissues and are also found in animal tissues like liver and muscle
Carbohydrates
103
most important source of energy
Carbohydrates
104
either a polyhydroxyaldehyde or polyhydroxyketone
Carbohydrate Molecule
105
the building block of starch and cellulose
Glucose
106
plants produce glucose through
photosynthesis
107
Carbohydrates are divided into 4 major classes
monosaccharide, disaccharide, oligosaccharide and polysaccharide
108
it cannot be hydrolyzed into simpler carbohydrate molecules
Monosaccharides or Simple sugars
109
most important monosaccharide from ther standpoint of foods and nutrition
hexoses
109
one alcohol group in a polyhydric alcohol is oxidized to either an eldehyde or ketone
Simple sugar
110
first oxidation product of a polyhydric alcohol in which either an end alcohol group is oxidized to form an aldehyde (aldose) or a secondary alcohol group is oxidized to a ketone (ketose)
Monosaccharide
111
Trioses
C3H6O3
112
Tetroses
C4H04
113
Pentoses
C5H10O4
114
yield two monosaccharide molecules when hydrolyzed
Disaccharides
115
glucose + fructose =
sucrose
116
Reducing Disaccharides
lactose, maltose, cellobiose
117
Non-reducing disaccharide
sucrose
118
yield 3-20 monosaccharide molecules
oligosaccharides
119
examples of oligosaccharide
Trisaccharide, C18H32O16 - raffinose
120
yield many monosaccharide molecules upon hydrolysis
polysaccharides
121
examples of polysaccharides
starch, glycogen, cellulose
122
Pentosans
Araban, Xylan
123
Hexosans
Glucosans. Fructosans, Mannosans
124
Mixed Polysaccharides
Gums Mucilages Hemicellulose Compund celluloses
125
Physical Properties of Mono and Disaccharides
crystalline, soluble in water
126
Chemical Properties of Mono and Disaccharides
1. the action of non-oxidizing acids 2. the action of alkali on carbohydrates 3. oxidation of sugars 4. reducing property of sugars 5. reduction of sugars 6. reactions of sugars with phenylhydrazine 7. ester formation

Biochemistry (9 decks)

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