Midterm Flashcards
(146 cards)
1
Q
catalysts for biological reactions
A
enzymes
2
Q
Enzymes can become inactive when they coagulate during:
A
Heating Treatment with: alcohol salts of heavy metals acids and bases
3
Q
inorganic or organic substance which speeds up the rate of a chemical reaction without itself entering the reaction
A
Catalyst
4
Q
organic catalysts made of protein
A
Enzymes
5
Q
How do enzymes catalyze?
A
They lower the activation energy needed to start the chemical reaction
6
Q
Enzymes begin to be destroyed at:
A
above 45 degrees Celsius
7
Q
The enzyme must form a _________ with the substance or substances whose reaction rate it affects
A
temporary association
8
Q
The association between enzyme and substrate is thought to form a close physical association between the molecules and is called-
A
enzyme-substrate complex
9
Q
While the enzyme-substrate complex is formed,
A
enzyme action takes place
10
Q
Upon completion of the reaction, the enzyme and product(s)-
A
separate
11
Q
molecules upon which an enzyme acts
A
substrate
12
Q
The enzyme is shaped so that it can only lock up with-
A
a specific substrate molecule.
13
Q
Each enzyme is specific for
A
one and only one substrate
14
Q
Source of catalase
A
potato
15
Q
Role of catalase
A
Decomposition of hydrogen peroxide
16
Q
Source of glutatione
A
animal cells
17
Q
Role of glutathione
A
Protects red cells from oxidation damage
18
Q
Source of oxidase
A
living cells
19
Q
Role of oxidase
A
Oxidizes carbohydrates, fats and proteins
20
Q
Enzymes end in
A
-ase
21
Q
Enzymes that identify reacting substance:
A
sucrase-reacts sucrose
lipase - reacts lipid
22
Q
Enzymes that describe function of enzyme
A
oxidase-catalyze oxidation
hydrolase - catalyze hydrolysis
23
Q
Common names of digestion enzymes use:
A
-in
24
Q
Examples of digestion enzymes
A
pepsin, trypsin, chymotrypsin
25
Classifications of Enzymes
```
Oxidoreductases
Transferases
Hydrolases
Lyases
Isomerases
Ligases
```
26
Reaction catalyzed by oxidoreductases
oxidation-reduction
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Reaction catalyzed by Transferases
transfer group of atoms
| movement of a functional group from one molecule to another
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Reaction catalyzed by Hydrolases
hydrolysis
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Reaction catalyzed by Lyases
add/remove atoms to/from a double bond
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Reaction catalyzed by Isomerases
rearrange atoms
31
Reaction catalyzed by Ligases
combine molecules using ATP
32
LER
reducing agent (redox)
33
GEO
oxidizing agent
34
basic reaction of Transferases
AX + B ------> A + BX
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Lyases catalyze the cleavage of:
C-C, C-O,C-S and C-N bonds by any other means than hydrolysis or oxidation
36
- the reduction of methylene blue to methylene white by formaldehyde is rapidly catalyzed by fresh milk but not by boiled milk
- an example of oxidation in the absence of O2 with an organic hydrogen acceptor
Schardinger Reaction
37
catalyzing enzyme present in Schardinger reaction
xanthine oxidase
38
organic hydrogen acceptor in Schardinger reaction
methylene blue
39
Reactants in TT1
Boil --> Methylene Blue --> mix --> paraffin oil --> water bath
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Reactants in TT2
Methylene Blue --> formalin --> mix --> paraffin oil --> water bath
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Reactants in TT3 (Control)
Methylene blue --> mix --> paraffin oil --> water bath
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Reaction in TT1
Light blue
| did not decolorize after heating
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Reaction in TT2
Light blue
| decolorizes after to white heating
44
Reaction in TT3 (Control)
Light blue
| decolorizes to white after heating
45
- is a compound containing three amino acids
- an antioxidant in the body
- vital component in the destruction of free radicals
- detoxification of harmful substances within the body
glutatione
46
three amino acids in glutathione
glutamate
cysteine
glycine
47
- Test used for detecting the presence of free thiol groups of cysteine in proteins
- used for the identification of ketones in urine testing
Nitroprusside Reaction
48
The color that indicates positive result in Nitroprusside Test
red
49
Factors that affect the speed of decomposition of hydrogen peroxide by catalase:
concentration of catalase
concentration of hydrogen peroxide
hydrogen ion concentration
temperature
50
reaction involved in liver catalase
absorption of hydrogen peroxide at the catalase surface
51
The optimum pH of catalytic decomposition of H2O2
6.8 - 7.0
52
Reaction in liver catalase
Liver + H2O ------> H2O + O2 (bubbles)
53
Roles of catalase in liver
- common antioxidant enzyme
- helps body break down H2O2, thus prevents accumulation of CO2 bubbles in the blood
- very potent enzyme; can decompose millions of H2O2
- uses H2O2 to oxidize harmful toxins
54
Potentially harmful toxins oxidized by H2O2
formaldehyde
formic acid
alcohol
phenol
55
chemicals used in Nitroprusside test
sodium nitroprusside
| ammonium hydroxide
56
the substance added to the mixture of milk and methylene blue to prevent oxygen from reacting with oxidase
paraffin oil
57
The compound responsible for the rapid reduction of methylene blue to methylene white in the presence of the enzyme present in milk
formaldehyde
58
It is a group present in proteins that is being liberated in Nitroprusside Reaction for Glutathione to indicate a positive result
thiol
59
It is an enzyme from potato responsible for the decomposition of hydrogen peroxide
catalase
60
Source of catalase in animal enzyme activity
liver
61
Source of specimen for vegetable/fruit oxidase and catalase:
potato
guava
chico
apples
62
oxidizes carbohydrates, fats and proteins (main source of body energy)
found in living cells
Oxidase
63
- a biochemical process in which fruit or vegetable tissues turn brown when exposed to oxygen
- one of the most important color reactions that affects fruits, vegetables and seafood
- can adversely affect flavor and nutritional value
Enzymatic browning
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Enzymatic browning is catalyzed by:
polyphenol oxidase or phenolase
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Enzymatic browning takes place at:
warm temperature
| pH 5.0 - 7.0
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Enzymatic browning can economically benefit:
tea, coffee, cocoa, chico
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Enzymatic browning can economically jeopardize:
fruits and vegetables
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in the presence of oxygen from the air, this enzyme catalyzes the formation of brown pigments called melanin
phenolase
69
Ways to reduce enzymatic browning
1. Treatment of slices with organic substances such as ascorbic acid, citric acid or acetic acid
2. Soaking in plain water
3. Heating
70
- acts as an antioxidant
- oxygen preferentially reacts with this rather than phenolic compounds in the fruit or vegetable
- browning does not proceed until all of it is used up in the reaction
- reacts with melanin to bleach them
ascorbic acid
71
lower the pH of the fruit tissue to retard the action of phenolase
Citric and acetic acid
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pH where phenolase will be deactivated
3.0
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restricts the amount of oxygen in contact with apple tissue
soaking in plain watter
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cannot be used as treatment for fruits which will be served fresh
heat
75
TT1 Potato Oxidase (Phenol)
During Exp: Cloudy
| Next Lab Period: Red/brown
76
TT2 Potato Oxidase ( Pyrogallol)
During Exp: colorless
| Next lab period: From colorless to purple because it absorbed oxygen from air
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toxic white with slightly pink shade crystalline solid
phenol
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phenol is also known as
carbolic acid
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formula of phenol
C6H6O
80
white crystalline powder
| powerful reducing agen
Pyrogallol
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formula of pyrogallol
C6H6O3
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uses of pyrogallol
hair drying
| developing agent in black and white photos
83
an enzyme that catalyzes the reduction of H2O2 liberating O and H2O
catakase
84
Reagents in TT1 Vegetable catalase
potato extract
| H2O2
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Reagents in TT2 Vegetable Catalase
boiled potato extract
| H2O2
86
Reagents in TT3 (control) vegetable catalase
Water
| H2O2
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Reaction in TT1 Vegetable catalase
produced bubbles
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Reaction in TT2 Vegetable catalase
did not produce bubbles
89
Reaction in TT3 Vegetable catalase
does not produce bubbles
90
Factors that influence enzyme activity
```
concentration of enzyme
concentration of substrate
pH
Inorganic salts of heavy metals
Presence of activators (co-enzymes) and inhibitors (anti-enzymes)
```
91
Tests for Carbohydrates
```
Iodine Test
Fehling's Test
Benedict's Test
Barfoed's Test
Picric acid Test
Seliwanoff's Test
Moore's Test
Molisch's Test
Trommer's Test
Mucic Acid Test
```
92
- specific test for starch
| - test for dextrin
Iodine test
93
Reagent composition and color of Iodine test
Iodine
| brown
94
Positive result in Iodine Test
Starch - dark blue
| Dextrin - purple
95
- test for sugar
| - tests the presence of aldehydes but not ketones
Fehling's test
96
Reagent composition and color of Fehling's test
A - CuSO4
B- NaOH + Na K Tartrate
Dark blue
97
Positive result of Fehling's test
Brick red precipitate
98
- sensitive test for the presence of sugar in urine
| - test determine whether a monosaccharide or disaccharide is a reducing sugar
Benedict's test
99
Reagent composition and color of Benedict's test
CuSO4 + Na Citrate + Na2CO3
| Light blue
100
Positive result of Benedict's test
Brick red precipitate
101
- differentiates mono and disaccharides
| - similar to Fehling's test, except that different types of sugars react at different rates
Barfoed's test
102
Reagent composition and color of Barfoed's Test
```
Copper acetate (CuAc)
Acetic acid (HAc)
```
light blue
103
Positive result of Barfoed's test
Brick red precipitate
104
- test for the formation of sodium picramic acid/ picramate
Picric acid test
105
Reagent composition and color of Picric acid test
Picric acid
| yellow
106
Positive result of Picric acid test
Mahogany red solution
107
- distinguishes aldose (-) from ketose (-)
| - specific test for fructose
Seliwanoff's test
108
Reagent composition and color of Seliwanoff's test
Resorcinol + HCl
| yellow
109
Positive result of Seliwanoff's test
Cherry red compound/complex
110
test based on the liberation of aldehyde
Moore's test
111
Reagent composition and color of Moore's test
NaOH
| Colorless
112
Positive result of Moore's test
Brown color with caramel-like odor
113
general test for carbohydrates
Molisch's test
114
Reagent composition and color of Molisch's test
alphanaphthol in alcohol layered with H2SO4
red orange
115
Positive result of Molisch's test
violet ring
116
specific test for glucose
Trommer's test
117
Reagent composition and color of Trommer's test
CuSO4 + NaOH
| blue
118
Positive result of Trommer's test
glucose - red precipitate
| water - black
119
specific test for galactose
Mucic Acid test
120
Reagent composition and color of Mucic Acid test
HNO3
| colorless
121
Positive result of Mucic Acid test
galactose - white flaked crystals
| lactose - glucose interferes making fine elongated crystals
122
Positive and negative results in Fehling's test
Positive: glucose, maltose, fructose, lactose, galactose
negative: sucrose
123
Positive and negative results in Benedict's test
Positive: glucose, maltose, fructose, lactose, galactose
negative: sucrose
124
Positive and negative results in Barfoed's test
Positive: glucose, fructose, galactose
negative: sucrose, maltose, lactose
125
Positive and negative results in Picric Acid test
Positive: glucose, maltose, fructose, lactose, galactose
negative: sucrose
126
Positive and negative results in Seliwanoff's test
Positive: sucrose, fructose
Negative: Glucose, Maltose, galactose, lactose
127
Positive and negative results in Moore's test
Positive: glucose, maltose, fructose, lactose, galactose
negative: sucrose
128
Positive and negative results in Molisch's test
all positive
129
- an intermediate product before the final change of starch into sugar
- has same chemical formula as starch but possesses different properties
- smaller and less complex structure to starch that is formed during hydrolysis of starch
Dextrin
130
formula of dextrin
(C6H10O5)n
131
- are polyhydroxyaldehydes or polyhydroxy ketones
| - substances that yield these compounds upon hydrolysis
carbohydrates
132
means "containing several alcohol groups"
Polyhydroxy
133
are alcohols and are also either aldehydes or ketones
simple carbohydrates
134
Difference of Reducing sugars from non-reducing sugars
Reducing:
- possess a free aldehyde or ketone
- can reduce cupric ions to cuprous ions in Fehling's or Benedict's solution that precipitate out as Cu2O cuprous oxide
- oxidized by mild oxidizing agents
135
Difference of Non reducing sugars from reducing sugars
Non-reducing:
- free aldehyde or ketone is lacking
- no brick red precipitate
- not oxidized by mild oxidizing agents
136
exist in solution as an equilibrium of open chain and closed ring structures
sugars
137
carbon atom that contains the C=O bond in the open chain form
carbonyl carbon
138
the carbonyl carbon is the one which is attached to the O of the ring and an OH group
closed ring (cyclic)
139
type of sugar that is a reducing sugar
all common monosaccharides
140
reducing disaccharides
lactose and maltose
141
disaccharide that is a non-reducing sugar
sucrose
142
common oxidizing agents used to test for the presence of a reducing sugar
Benedict's solution
| Fehling's solution
143
result when closed ring opens to form a chain
alkanal
| alkanone
144
sugars that are aldehydes
aldoses
145
sugars that are ketones
ketoses
146
Advantages of Benedict's solution over Fehling's
1. Sensitive test for glucose thus used in urine test
2. More sensitive to reducing sugars
3. Not affected by uric acid, creatinine, chloroform, formalin which are sometimes employed as preservatives in urine
