Chem Exam 3 Flashcards
(115 cards)
1
Q
What are fatty acids?
A
Carboxylic acids that typically contain between 12 and 20 carbon atoms.
2
Q
What is the structure of fatty acids?
A
Fatty acids contain a head and a tail.
The tail contains one CH3 and fourteen CH2.
The head contains one C = O and one C – OH
3
Q
What does saturated mean?
A
A saturated fatty acid has only single bonds joining the carbon atoms in their hydrocarbon tails.
4
Q
What does monounsaturated mean?
A
Monounsaturated fatty acids have just ONE carbon-carbon double bond.
5
Q
What does polyunsaturated mean?
A
Polyunsaturated fatty acids have TWO or more double bonds.
6
Q
What is an example of a saturated fatty acid?
A
stearic acid
7
Q
What is an example of a monounsaturated fatty acid?
A
oleic acid
8
Q
What is an example of a polyunsaturated fatty acid?
A
linoleic acid
linolenic acid
9
Q
Do unsaturated fatty acids melt and boil at higher or lower temps?
A
Unsaturated fatty acids melt and boil at lower temperatures.
10
Q
Do melting and boiling points change with the length of saturated fatty acids?
A
Yes. The melting and boiling points of saturated fatty acids increase with increasing length.
11
Q
True or false:
For fatty acids with the same number of carbon atoms, the more unsaturated they are, the lower their melting points and boiling points.
A
TRUE.
12
Q
Are unsaturated fatty acids liquid or solid at room temp?
A
Unsaturated fatty acids are LIQUIDS at room temp.
13
Q
True or false:
Oleic, linoleic, and linolenic acids are all nonessential fatty acids that have 16 carbon atoms.
A
FALSE.
Oleic, linoleic, and linolenic acids are all ESSENTIAL fatty acids that must be acquired in the diet, and they all have 18 CARBON ATOMS.
14
Q
What is the structure of oleic acid?
A
CH3(CH2)7CH=CH(CH2)7CO2H
15
Q
What is the structure of linoleic acid?
A
CH3(CH2)4(CH=CHCH2)2(CH2)6CO2H
16
Q
What is the structure of linolenic acid?
A
CH3CH2(CH=CHCH2)3(CH2)6CO2H
17
Q
What is the structure of a wax?
A
Fatty acid–Alcohol
18
Q
Define waxes.
A
Waxes are mixtures of water insoluble compounds, including esters, alcohols, and alkanes.
19
Q
Define residue.
A
The part of a reactant molecule that remains when it has been incorporated into a product.
20
Q
What are triglycerides?
A
Animal fats and vegetable oils, in which three fatty acid residues are joined to a glycerol residue by ester bonds.
Also known as triacylglycerides.
Fatty acid—
Fatty acid— Glycerol
Fatty acid—
21
Q
What is the structure of a glycerol?
A
HO---CH2
!
HO---CH
!
HO---CH2
22
Q
What are the 4 important reactions of triglycerides?
A
- Hydrogenation
- Partial hydrogenation
- Oxidation
- Saponification
23
Q
What is hydrogenation?
A
Hydrogenation is a reduction reaction which results in an addition of hydrogen (usually as H2).
24
Q
If an organic compound is hydrogenated, what happens?
A
If an organic compound is hydrogenated, it becomes more ‘saturated’.
25
True or false:
Hydrogenation does not require a catalyst.
FALSE.
Hydrogenation DOES require a catalyst.
26
What is partial hydrogenation?
In partial hydrogenation, only some of the carbon-carbon bonds are removed.
27
Does partial hydrogenation require a catalyst?
YES. Partial hydrogenation does require a catalyst.
28
What is oxidation?
Oxidation is the loss of electrons during a reaction by a molecule, atom or ion.
29
What is saponification?
Soap making.
When triglycerides are saponified, glycerol and fatty acid salts (soap) are produced. Soaps are amphipathic compounds that form monolayers and micelles.
The ionic compound NaOH is the source of the OH- used in the reaction shown here.
30
What are trans fats?
Partial hydrogenation fo unsaturated vegetable oil converts some of the carbon-carbon double bonds from cis into trans isomers.
31
What is olestra's basic structure?
Olestra's basic structure is that of the carbohydrate, sucrose, to which fatty acids have been attached by esterification reactions & via the hydroxyl groups of sucrose.
32
Define amphipathic.
A term used to describe substances that have both hydrophilic and hydrophobic parts.
33
True or false:
Membranes are composed of a double layer of amphipathic phospholipids.
TRUE. Membranes are composed of a double layer of amphipathic phospholipids.
34
What is the structure of a glycerophospholipid?
A glycerophospholipid is made by combining glycerol, two fatty acids, one phosphate group, and one alcohol-containing compound.
35
What are the 3 types of glycerophospholipids?
1. Phosphatidylcholine (lecithin)
2. Phosphatidyethanolamine (cephalin)
3. Phosphatidylserine
36
What is [N.C. = (-) + (+) = 0]
Phosphatidylcholine (lecithin)
or
Phosphatidyethanolamine (cephalin)
37
What is [N.C. = (-) + (+) + (-) = -1]?
Phosphatidylserine
38
What is the net charge of phosphatidylcholine?
0
39
What is the net charge of phosphatidyethanolamine?
0
40
What is the net charge of phosphatidylserine?
-1
41
What do the 3 types of glycerophospholipids cause?
The 3 types of glycerophospholipids can cause the phospholipid to have different overall net charges.
42
How are glycolipids formed?
Glycolipids are formed by combining sphingosine, a fatty acid, and a sugar.
43
What is the structure of sphingosine?
CH3(CH2)11CH2CH=CHCHOH
!
+!
H3NCH
!
CH2OH
44
What are cerebrosides?
Simple sugars used to produce the glycolipids. They are found at nerve synapses and in the brain.
45
What are gangliosides?
Another class of glycolipids that are made using a chain of simple sugars. Gangliosides are important in nerve membranes and act as cell surface receptors for hormones and drugs.
46
True or false:
The sugar molecules in some gangliosides help determine blood type.
TRUE.
The sugar molecules in some gangliosides help determine blood type.
47
What is cholesterol?
Cholesterol is the starting material for the biosynthesis of many compounds such as sex hormones, adrenocorticoid hormones, and bile salts.
48
What are the 4 types of lipoproteins?
1. Chylomicrons
2. VLDLs
3. LDLs
4. HDLs
49
What are lipoproteins?
Lipoproteins are responsible for transporting various lipids through the blood.
50
What do chylomicrons carry?
Mainly triglycerides
51
What do low density lipoproteins carry?
Triglyverides, phospholipids, and cholesterol.
52
What is the function of lipoproteins?
To transport cholesterol and phospholipids from the liver to the cells, where they are incorporated into membranes or, in cases of cholesterol, transformed into other steroids.
53
Rank the order of lipoproteins from highest to lowest in terms of triglycerides.
Highest to lowest:
Chylomicrons
VLDLs
LDLs
HDLs
54
Rank the order of lipoproteins from highest to lowest in terms of phospholipids.
Highest to lowest:
HDLs
LDLs
VLDLs
Chylomicrons
55
Rank the order of lipoproteins from highest to lowest in terms of chloesterol.
Highest to lowest:
LDLs
VLDLs
HDLs
Chylomicrons
56
Rank the order of lipoproteins from highest to lowest in terms of protein.
Highest to lowest:
HDLs
LDLs
VLDLs
Chylomicrons
57
What are eicosanoids?
Eicosanoids are derivatives of arachidonic acid.
58
What are the 3 derivatives of arachidonic acid?
Prostaglandins
Thromboxanes
Leukotrienes
59
How do NSAIDS block the formation of prostaglandins and thromboxanes from arachidonic acid?
Nonsteroidal, anti-inflammatory agents (NSAIDS) can block the formation of prostaglandins and thromboxanes from arachidonic acid by blocking the enzyme that converts arachidonic acid into the two products.
60
What is an example of an NSAID?
Aspirin
61
Are membranes permeable or semipermiable?
Membranes are selectively permeable, and can pass molecules by diffusion, facilitated diffusion, or active transport.
62
What is diffusion?
Nonpolar molecules diffuse across membranes moving in the direction of higher concentration to lower concentration.
63
What is facilitated diffusion?
Some polar molecules diffuse through a protein channel that spans the membrane.
64
What is active transport?
Some molecules and ions are transported across membranes in the direction of lower to higher concentration in an energy-requiring process.
65
In the Bronsted-Lowry definition do acids or bases accept H?
In the Bronsted-Lowry definition bases accept H+ and acids release H+.
This reaction is REVERSIBLE.
66
Describe conjugates.
An acid and its conjugate base differ by the presence of H+.
Compounds, such as HCN and CN- or NH3 and NH4+, which differ only in the presence or absence of H+, and are called conjugates.
67
Define equilibrium.
At equilibrium the rate of the forward and reverse reactions are the same and concentrations of reactants and products do not change.
68
In equilibrium constants, what do the brackets symbolize?
Brackets symbolize "Molar concentration."
69
What is the general formula for equilibrium constants?
aA + bB =(reversible) cC + dD
70
What does Keq stand for?
Keq = equilibrium constants
71
What is the equilibrium constant also known as?
Keq is also known as the "acidity constant"
72
What does teh Le Chateliers principle state?
The Le Chatelier's principle states that when a reversible reaction is pushed out of equilibrium, the reaction responds to reestablish equilibrium.
73
What do catalysts do?
Catalysts increase reaction rates by lowering the activation energy. When a catalyst is used in a reversible reaction the lowered activation energy speeds up the forward and reverse reactions to the same extent.
74
How do catalysts affect equilibrium and keq?
The overall result is that a catalyst has no effect on an equilibrium or on the value of keq.
75
What is an amphoteric compound?
A compound that can act as an acid or a base.
76
True or false:
Water is amphoteric because it can act as either an acid or a base, depending on what it reacts with.
TRUE.
Water is amphoteric because it can act as either an acid or a base, depending on what it reacts with.
77
What is H3O+
Hydronium
78
What is OH-
Hydroxide
79
When is an aqueous solution acidic?
An aqueous solution is acidic when the concentration of H3O+ is greater than 1 x 10-7 M, and the higher the concentration the more acidic it is.
ph < 7
80
When is an aqueous solution a basic?
An aqueous solution is basic when the concentration of H3O+ is less than 1 x 10-7 M, and the lower the concentration, the more basic it is.
pH > 7
81
When is an aqueous solution neutral?
When the concentration of H3O+ equals 1 x 10-7 M
pH = 7
82
Describe strong acids.
Strong acids:
completely ionizes in water
Larger Ka
Results in low pH
Have weak conjugate bases
83
Describe weak acids.
Weak acids:
incomplete ionization in water
smaller Ka
more moderate pH
84
Define dissociates.
Falls apart
85
Do strong bases completely or incompletely dissociate (ionize) in water?
Strong bases completely dissociate (ionize) in water
86
What is an example of a strong base?
NaOH
87
Do weak bases completely or incompletely dissociate (ionize) in water?
Weak bases incompletely ionize in water
88
What is an example of a weak base?
ammonia
89
True or false:
The weaker an acid, the weaker its conjugate base.
FALSE.
The STRONGER an acid, the weaker its conjugate base.
90
What is the general expression for acid (HA) and conjugate base (A-)?
HA H+ + A-
91
True or false:
The relative amounts of HA and A- in a solution depend upon pH.
TRUE.
The relative amounts of HA and A- in a solution depend upon pH.
92
Define buffer.
A buffer is a solution that resists changes in pH when small amounts of acid or base are added.
93
How do buffers resist change?
Give an example.
Buffers are most resistant to pH changes when the pH equals the pKa of the weak acid and are effective when the pH is within one unit of the pKa.
Acetic acid pK = 4.74, and the acetic acid/acetate ion buffer is most effective over pH range of 3.74 5.74
94
Why must the pH of the blood be kept within narrow limits?
The pH of blood serum must be kept within limits because of the effect that pH variations have on the ability of enzymes to function properly.
95
What is the range that blood serum must be kept in?
7.35-7.45
96
Can protein enzyme structure be changed?
Yes. Protein enzyme structure can be changed by changing pH, and this may inactivate the protein enzyme.
97
True or false:
Acids produced by metabolism (all of the chemical reactions occurring within a living organism) can not affect blood pH.
FALSE.
Acids produced by metabolism (all of the chemical reactions occurring within a living organism) CAN affect blood pH.
98
How does the body handle excess acid?
Give examples.
The body handles excess acid via buffers.
Examples:
1. Carbonic acid (H2CO3)/bicarbonate (HCO3-) buffer
2. Dihydrogenphosphate (H2PO4-)/hydrogenphosphate (HPO42-)
3. Proteins can also act as buffers
99
Can the rate of breathing modify blood concentrations?
Yes. The rate of breathing can modify blood concentrations of CO2.
100
What do the kidneys do?
Kidneys can remove HCO3- from blood and can remove H3O+ from blood.
Kidneys can add HCO3- to blood and can add H3o+ to blood.
H3O+ is excreted into urine.
101
What is acidosis?
a low blood serum pH
can cause light-headedness and in severe cases, coma and death.
102
What is alkalosis?
a high blood serum pH
can cause headaches, nervousness, cramps, and in severe cases compulsions and death.
103
What is the mathematical expression for pH?
pH = -log[H3O+] = -log(8 x 10-4) = -(-3.1) = 3.1
104
What is the mathematical expression for pKa?
pKa = -log Ka
The lower the pKa, the stronger the acid.
105
What is the pKa of phosphoric acid (H3PO4)?
The pKa of phosphoric acid (H3PO4) is 2.12
106
What is the pKa of dihydrogenphosphate ion?
The pKa of dihydrogenphosphate ion is 7.21
107
What is the pKa of hydrogenphosphate ion?
The pKa of hydrogenphosphate ion is 12.38
108
What is the pKa of carbonic acid?
The pKa of carbonic acid is 6.36
109
What is the pKa of ammonium ion?
The pKa of ammonium ion is 9.25
110
What is NH4+?
Ammonium ion
111
What is H2CO3-?
Carbonic acid
112
What is H+ + Dihydrogenphosphate ion?
H2PO4-
113
What is H+ + Hydrogenphosphate ion?
HPO4 2-
114
What is H+ + Phosphate ion?
PO4 3-
115
What is H3PO4?
Phosphoric acid
