water and buffers Flashcards
1
Q
resists pH change
A
buffers
2
Q
what is the pH range of blood?
A
7.35-7.45
3
Q
what is the abundant buffer in human body?
A
bicarbonate (carbonic acid)
4
Q
this is the most abundant component of every cell
A
water
5
Q
everything that happens in cells, even reactions buried deep inside enzymes, away from water, is influenced by
A
water’s chemistry
6
Q
needed in catabolic processes
A
water
7
Q
this dissolves salts
A
water
8
Q
electrolyte are dissolved what?
A
dissolved ions
9
Q
uric acid forms what?
A
oxalates
10
Q
is a measure of the tendency of an atom to attract a bonding pair of electrons
A
electronegativity
11
Q
electronegativity follows this trend
A
periodic trend
12
Q
this is the relative “pull” of nuclei for outer shell electrons
A
electronegativity
13
Q
these electrons are responsible for bonding
A
valence electrons
14
Q
nonmetal have what charges?
A
negative charges
15
Q
what elements have the highest electronegativity?
A
F, O, N, Cl
16
Q
it is the most commonly used electronegativity values
A
pauling scale
17
Q
the most electronegative element
A
fluorine (4.0)
18
Q
the least electronegative elements
A
cesium and francium (0.7)
19
Q
unlike charges
A
attraction
20
Q
water is a what molecule?
A
polar molecule
21
Q
water is a polar molecule because charges are distributed around it _____, not ______
A
unevenly; symmetically
22
Q
CO2 is a what molecule?
A
nonpolar, but has polar bonds
23
Q
μ=0
A
molecular dipole of CO2
24
Q
if same force (both sides) for the pull of nuclei then it is
A
nonpolar
25
to break the hydrogen bonds (H bonds), what do you need to do?
heat
26
which is greater in size? cation or anion?
anion
27
nadadagdagan ng electron
anion (negative)
28
namimigay ng electron
cation (positive)
29
what is the meaning of this δ-?
partial negative
30
what is the meaning of this δ+?
partial positive
31
the uneven charge distribution in the water molecule makes it ____ and form _____ BONDS
dipolar; hydrogen bonds
32
this dipole is bonding from the atoms
bond dipoles
33
entire molecule bonding
molecular dipole
34
the water molecule has wide ___ shape (the HO-H angle is ____) with ____ sharing of electrons between the oxygen and the hydrogen atoms.
V; 104.3°; uneven
35
____ is described as a SOLVENT because of its ability to dissolve many, but not all, molecules
water
36
they are soluble in water
polar molecules and ionic compounds
37
they are soluble in oils and fats
nonpolar molecules
38
t or f: all nitrates are soluble in water
true
39
any process by which electrically neutral atoms or molecules are converted to electrically charged atoms or molecules (ions) through gaining or losing electrons
ionization
40
AgNO3 + H2O -> Ag + NO3(aq) + Cl
AgCl(s)
41
alcohol is ____scopic
hygroscopic
42
Oil, which is _____, separates from water when mixed with it. Sodium chloride, which ____, and ethanol, which is ____, can both dissolve in water.
nonpolar; ionizes; polar
43
Ethanol’s solubility in water is crucial for brewers, winemakers, and distillers. If ethanol does not mix with water, there would be no wine, beer or spirits
true ka jan
44
____ solubility uses the like dissolves like rule
covalent
45
substances with the same type of polarity will be ______ in one another
soluble
46
compounds with differing polarities will be ____ in one another
insoluble
47
describes substances that interact well with water and dissolve in it
hydrophilic
48
refers to materials that are non-polar and do not dissolve in water
hydrophobic
49
nonpolar hydrocarbons (hexane); lipids (fats and cholesterol)
hydrophobic
50
ionic compounds, polar organic compounds, weak acids, sugars
hydrophilic
51
refers to compounds that have both (hydrophilic and hydrophobic) properties
amphiphilic
52
____, for example are AMPHIPHILIC, containing a long, ____ and a _____
soaps; nonpolar aliphatic tail; head that ionizes
53
the ______ PORTIONS of the soap ions associate with each other and exclude water
nonpolar
54
the result is that the soap ions arrange themselves as _____ with the _____ PORTIONS on the interior of the structure away from water and the ____ PORTIONS on the outside interacting with water
micelles; nonpolar; polar
55
other amphiphilic substances
membrane lipids
56
types of membrane lipids
glycerophospholipids and sphingolipids
57
liposome has how many layers?
two layers
58
the interaction of the polar heads with water returns the water to its more disordered state. this increase in disorder, or ______, drives the formation of micelles
entropy
59
the same forces drive glycerophospholipids and sphingolipids to spontaneously form ____
lipid bilayers
60
_____ portions of the molecules interact with each other to exclude _____
nonpolar; water
61
_____ portions arrange themselves on the outsides of the bilayer
polar
62
another example is seen in the folding of _____PROTEINS in the cytoplasm
globular
63
____ amino acids are found in the _____ portion of the protein (water excluded)
nonpolar; interior
64
interaction of the nonpolar amino acids turns out to be a driving force for the folding of proteins as they are being made in an aqueous solution
trulalu
65
these tiny charges (δ+ and δ-) result in formation of _____, which occur when the partial positive charge of a hydrogen atom is attracted to the partial negative of another molecule
hydrogen bonds
66
in water, that means the _____ of one water molecule is attracted to the _____ of another
hydrogen; oxygen
67
since water is an _____ molecule, it means also that the charges are ______
asymmetrical; asymmetrical
68
such an uneven distribution is what makes a _____
dipole
69
are important for interactions with other dipolar molecules and for dissolving ionic substances
dipolar molecules
70
the _____ BONDS in biochemistry are very important and cannot be overemphasized
hydrogen
71
proton acceptor
base
72
proton donor
acid
73
t or f: hydrogen bonds are not exclusive to water
true
74
they are important forces holding together macromolecules that include proteins and nucleic acids
hydrogen bonds
75
these bonds occur within and between macromolecules
hydrogen bonds
76
each hydrogen bond is relatively ____ (compared to a covalent bond) but collectively they can be quite ____
weak; strong
77
occurs between bases in opposite strands of DNA is based on hydrogen bonds
complementary base pairing
78
also play roles in binding of substrates to enzymes, catalysis, and protein-protein interaction, as well as other kinds of binding, such as protein-DNA, or antibody-antigen
hydrogen bonds
79
hydrogen bonds are ____ than _____ bonds and their strength varies from very weak (___ kJ/mol) to fairly strong (___ kJ/mol)
weaker; covalent; 1-2; 29
80
the farther apart the hydrogen bond distance is, the ____ the bond is
weaker
81
hydrogen bonds only occur over relatively ____ distances (_____ Å)
short; 2.2-4.0
82
covalent bonds are ___ to break
harder to break
83
their weakness (hydrogen bonds), however, is actually quite beneficial for cells, particularly as regards ____
nucleic acids
84
the strands of DNA, for example, must be separated over ____ stretches in the processes of _____ and the _______
short; replication; RNA synthesis
85
the _____ represents the amount of heat that must be put into the system to break the bond – the larger the number, the _____ the strength of the bond
strength of the bond; greater
86
hydrogen bonds are readily broken using ____
heat
87
the _____, for example, requires breaking of H-bonds
boiling of water
88
when a biological structure, such as a protein or a DNA molecule, is stabilized by hydrogen bonds, breaking those bonds ______ the structure and can result in ______ of the substance – loss of _____ and ____
destabilizes; denaturation; structure and function
89
it is partly for this reason that most proteins and all DNAs lose their _____, or _____, structures when heated to boiling
native; folded
90
for DNA molecules, denaturation results in ______ of the strands from each other
complete separation
91
for most proteins, denaturation means loss of their _____ and with it, loss of the ____ they performed
characteristic three-dimensional structure; function
92
t or f: Though a few proteins can readily reassume their original structure when the solution they are in is cooled, MOST CANT
trulalerls
93
This is one of the reasons that we cook our food. Proteins are essential for life, so denaturation of _____ proteins results in death of any microorganisms contaminating the food
bacterial
94
water can ionize to a slight
extent (___ M) to form ____ and ____
10^-7 M; H+ proton; OH- hydroxide
95
Kw means?
equilibirum constant of water
96
what is the autoionization constant for water at 25 degrees C?
Kw = [H+][OH-] (molar concentration) = 1.0 x 10^-14
97
the _____ of a solution is measured with pH, which is the ____ log of the ____ concentration.
proton concentration; negative; proton
98
formula for proton concentration
pH = -log [H+]
99
__________ is measured with the pOH by the parallel equation
hydroxide concentration
100
formula for hydroxide concentration
pOH = -log [OH-]
101
Chemists use the term “_____” to refer to a substance which has protons that can dissociate when dissolved in water (PROTON ____)
acid; donor
102
use the term “____” to refer to a substance that can absorb protons when dissolved in water (PROTON ______)
base; acceptor
103
a type of acids that are able to donate only one proton
monoprotic acid
104
a type of acids that are able to donate only two protons
diprotic acid
105
a type of acids that are able to donate only three protons
triprotic acid
106
______ acids dissociate completely when in aqueous solution
strong acids
107
____ acids dissociate only slightly in aqueous solution
weak acids
108
weak acids are critical for life because their affinity for protons causes them to behave like a ____
UPS
109
We can think of weak acids as __________ within certain pH ranges, _________ protons as needed
Uninterruptible Proton Suppliers; providing or absorbing
110
weak acids thus help to keep the _____ concentration (and thus the pH) of the solution they are in relatively _________
H+; constant
111
pH level of milk
6.5
112
can act as a buffer
milk
113
an acid and a base which differ only by the presence or absence of a proton are called a ________
conjugate acid-base pair
114
more hydrogen then it is a/an
acid
115
adding hydroxide ions (by adding a strong base like NaOH) to the solution causes the H+ ions to react with OH- ions to make water. Consequently, the concentration of H+ ions would _____ and the pH would ________
go down; go up
116
one way to determine the pH of a buffer is by using the ____________
Henderson–Hasselbalch equation
117
Henderson– Hasselbalch equation
pH = pKa + log([A-]/[HA])
118
The _____ is the _______ and is used to distinguish strong acids from weak acids. It is a measure of the strength of an acid
Ka; acid dissociation constant
119
acid dissociation constant formula
Ka = [H+][A-]/[HA]
120
strong acids have exceptionally _____ Ka values
high Ka values
121
the Ka value is found by looking at the ___________ for the dissociation of the acid
equilibrium constant
122
the higher the Ka, the ____ the acid dissociates
more the acid dissociates
123
large values of Ka translate to _____ values of pKa
lower (inversely proportional with pKa)
124
as a result, the lower the pKa value is for a given acid, the ______ the weak acid is
stronger
125
strong Acids, like HCl, essentially have ____ pKa value.
no pKa value
126
low pKa means
stronger weak acid
127
high pKa means
weaker weak acid
128
aspartic acid has how many regions?
three regions
129
aspartic has how many possible charges?
four charges (+1, 0, -1, -2)
130
How does one predict the charge for an amino acid at a given pH?
1) pH < pKa, proton on
2) pH > pKa, proton off
