pH, acidosis/alkalosis, membranes Flashcards
(112 cards)
1
Q
the isoelectric point (pI) is
a. the pH at which the number of positive and negative charges on a molecule equal each other
b. the pH at which the number of positive and negative charges in a solution equal each other
A
the pH at which the number of positive and negative charges on a molecule equal each other = the pH at which a solute has NO NET ELECTRICAL CHARGE and does not move in an electric field
2
Q
why is isoelectric point pI important?
A
soln containing a mixture of amino acids can be separated based on direction and relative rate of their migration when placed in an electric field at a known pH. same applies to proteins
3
Q
the pK is the property of __ group
A
individually ionized group (unlike pI = property of whole molecule)
4
Q
at a pH above an amino acids’ pI it will move
A
toward the positive electrode (the anode) when placed in electric field
5
Q
at physiologic pH ALL amino acids have
A
both a + charged amino group and a - charged COO group.
6
Q
at physiological pH all amino acids are called
A
zwitterions = dipolar ions
7
Q
given OH- concentration of 10^-4 M what is the pH
A
Kw = H+ x OH- Kw = 10^-14 (10^-14)/(10^-4) = H+ 10^-10 = H+ ==> take -log of each side pH = 10
8
Q
most important physiological buffer system in body is
A
carbonic acid and bicarbonate
9
Q
proteins are pH buffers mainly through their __ side chains
A
histidine
10
Q
the pH of plasma in arterial blood is
A
7.4
11
Q
the pH of plasma in venous blood is
A
6.35 (lower because CO2 in the form of carbonic acid is returning to lungs for exchange)
12
Q
Carbonic acid is formed _ from CO2 and water
A
spontaneously
13
Q
enzyme that accelerates formation of carbonic acid
A
carbonic anhydrase in erythrocytes
14
Q
the phosphate buffer is important only in the __ compartment
A
intracellular compartment in which phosphate is the major inorganic anion
15
Q
albumin has 16 histidine residues with pK values not far from the blood pH of 7.4. like phosphate, proteins are more important buffer systems where
A
in the cell (vs in the plasma)
16
Q
buffer systems are made up of
A
weak acid = proton donor
and a salt = conjugate base of an acid = proton acceptor
17
Q
hemoglobin is a major intracellular/extracellular buffer
A
intracellular
18
Q
can the Henderson hasselbalch equation predict dissociation constants
A
no
19
Q
Henderson hasselbalch equation used to
A
predict the pH that acid buffers work best at
20
Q
the larger the Ka the _ the acid
A
stronger
21
Q
pH = pKa when
A
acid is half neutralized
22
Q
the pH of a buffer system depends on the
A
pk of the weak acid and the ratio of molar concentrations of the weak acid and salt
23
Q
the optimum pH for an enzyme is the pH that facilitates the
A
most rapid reaction rate
24
Q
a buffer is most effective when pH = pKa but it still works well within _pH unit of its pKa
A
1
25
body uses all these to control acid base except:
a. excess acid excreted in urine
b. pH buffers in blood
c. excretion of CO2
d. filtering blood by the spleen
filtering blood by the spleen
26
body has 3 lines of defense against acidosis and alkalosis
buffer systems
alveolar ventilation
kidney excretion
27
the respiratory center in the __ responds directly to _ and _
medulla oblongata
| CO2 and pH
28
kidneys excrete
H+ in acidosis and HCO3- in alkalosis = long term mechanism that acts in hours or days
29
the pka of the bicarb-CO2 buffer system is
6.1
30
to calculate pH of blood =
6.1 + log (bicarb/0.03xCO2 partial pressure)
31
an arterial blood pH < 7.35 is called:
acidosis
acidemia
acidemia
acidosis is the pathological state that occurs from acidemia
32
arterial blood pH > ? is called alkemia
7.45
33
pathological state of alkemia is called
alkalosis
34
if you administer a high nitrous oxygen mixture (90:10) to a patient this will cause
respiratory depression = respiratory acidosis
35
most important lab test for distinction bw metabolic/respiratory acidosis is the determination of the total
plasma CO2.
36
in respiratory acidosis, the __ is the cause
high CO2 retention
37
in metabolic acidosis caused by
patient hyperventilating in an attempt to eliminate excess carbonic acid
38
the cell plasma membrane is a fluid mosaic of:
a. lipids and carbs
b. proteins and carbs
c. lipids and proteins
d. carbohydrates
lipids and proteins
39
carbohydrates are attached to proteins and lipids on the ___ of the cell membrane
exterior side of the cell membrane
40
our bodies make mostly strong/weak acids
weak acids ie. carbonic acids
| except HCl
41
why is membrane called fluid mosaic
bc lipid and proteins can diffuse laterally within the plane of the membrane
42
pH and H+ relationship is an __ relationship
inverse
43
integral proteins are associated with the hydrophobic/hydrophilic phase of the bilayer
hydrophobic
44
the pH of the ECF can be measured using
pH = pKa + log [HCO3-]/[CO2]
45
is it the ratio or the absolute values for bicarbonate and dissolved CO2 that determines pH
ratio!
pH = pKa + log [HCO3-]/[CO2]
46
when the ration of [HCO3-]/[CO2] is ___ pH is equal to 7.4
20:1
47
the body's normal ECF pH range is
7.35-7.45
48
our body is constantly making acids/bases?
acids = acids are waste products from our metabolism
49
about half of the molecules in an average membrane are
phospholipids
50
3 lines of defense for buffering? 1st line is?
chemical buffers = our first line of defense bc it is the fastest. reacts if it goes above 7.45 or below 7.35
51
if you are making a lot of acid = acidosis = reaction is favored which way?
CO2 + H2- H2CO3 H+ + HCO3-
reaction is favored to the left so the H+ will be soaked up
| you want your buffer to act like a base and soak up the hydrogens.
52
if you have alkalosis, shortage of H+ which way does the reaction shift
CO2 + H2- H2CO3 H+ + HCO3-
you want your buffer system to act as an acid and release more H+
will shift to the right = make more acid.
53
HPO4^2- + H+ H2PO4-
| is the monophosphate or the diphosphate the acid?
diphosphate is the acid. the mono is the base
54
proteins are made up of amino acids. they have 2 groups that can act like an acid and base
amine group can act as bases: NH2 ==> NH3+
| and carboxyl groups can acts as acids and release their H: COOH ==> H+
55
if we were acidodic we would want our proteins to act as bases
amine groups to work
56
buffers are great because they ___
| but not as good because
good bc they can act fast
| but not good bc can become saturated
57
membrane proteins are __ proteins
globular
58
our second line of defense for acid base balance after chemical buffers is
respiratory system
59
CO2 + H2- H2CO3 H+ + HCO3-
| if we raise our CO2 level, which way will we shift
CO2 + H20 H2CO3 H+ + HCO3-
| to the right = make more H+ = pH drops
60
Proteins account for about __ the total mass of most membranes
50%
61
a decrease our rate/depth of breathing we will ___ CO2 and make our body ___ pH
retain CO2 = hypoventilation = decreases the pH of the body
62
a decrease in CO2 will __ the pH
raise our pH
CO2 + H20 H2CO3 H+ + HCO3-
if CO2 is low, we soak up the H+
raise the pH
63
if we increase our rate and depth of breathing = CO2 will _ =
hyperventilation = increases pH of blood
64
the non polar side chains of integral membrane proteins interact with
membrane lipids
65
integral membrane proteins can be solubilized only with treatments that
destroy the lipid bilayer (action of detergents)
66
say you are in acidosis and your buffers only bring your pH to 7.28 how would you want your respiration to react
want to hyperventilate to get rid of CO2
CO2 + H20 H2CO3 H+ + HCO3-
if we hyperventilate our CO2 level comes down the equation shifts left and hydrogens get soaked up
67
peripheral membrane proteins interact with integral membrane proteins or the __ group of the membrane phospholipids
hydrophilic
68
say you are in acidosis and your buffers only bring your pH to 7.28, lungs hyperventilate and bring us to 7.31. Lungs are 2nd line of defense and also work pretty fast. But they too have limitations. so the third line of defense is
kidneys
69
biological membranes are __ structures only a few molecules thick
sheetlike
70
biological membranes consist mainly of
lipids and proteins (carbs are attached to exterior)
71
T/F the kidneys can make bicarb from scratch
true
72
the membrane lipids are small molecules with hydrophobic and hydrophilic groups that from lipid bilayers in aqeous media. the __ center of the bilayer forms a barrier to the flow of polar molecules
hydrophobic
73
proteins and lipids in membranes are held together by
| covalent/non covalent interactions
non covalent
74
ABG test = arterial blood gas test measures
amount of gas in blood (oxygen and CO2)
bicarb
and pH
75
the lipid distribution in the membrane is symmetrical or asymmetrical. why?
asymmetrical = bc most phospholipids in the CYTOPLASMIC inner and most of the glycolipids are in the exoplasmic leaflet
76
in respiratory acidosis we have
they have a pH that is low and a CO2 level that is high. the high CO2 is causing the low pH
77
what can cause high CO2?
emphysema (trap CO2 in lungs and blood)
pulmonary edema
chronic bronchitis = airways are inflamed and narrow.
opiod overdose
neuromuscular disease (myasthenia gravis, Guillian-Barre syndrome)
injury to brainstem
78
where are phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine found
INSIDE on cytoplasm
79
where are phosphatidylcholine and sphingomyelin found
OUTSDE (exoplasmic) leaflet
| = glycolipids
80
what are globular proteins
integral and peripheral proteins
81
globular proteins are held by __ interactions bw lipid and hydrophobic domains in the proteins
hydrophobic
82
the lipid bilayer is __ to small inorganic ions such as sodium and protons
impermeable
83
all non covalent structures are
fragile
84
can coenzymes and metabolic intermediates cross the membranes
no they are water soluble
85
electrical conductivity of lipid bilayer is low/high
low bc ions cant pass
86
in respiratory alkalosis, the pH is increased due to
decreased CO2
| CO2 + H20 H2CO3 H+ + HCO3-
87
why would your CO2 be low?
hyperventilating
88
if you go up in altitude you will hyperventilate/hypo?
hyperventilate bc there is less oxygen so you will try to breath faster to get more oxygen which makes you breathe off more co2
89
in anxiety/fear/pain you will hyperventilate/hypo?
hyperventilate
90
aspirin overdose would cause hyperventilate/hypo
hyperventilate = aspirin stimulates the breathing centers! unlike opium.
91
why doesn't aspirin (salicylic acid) cause acidosis?
because its effect on the respiratory system is greater
92
fever would cause you to hyperventilate/hypo
hyperventilate
93
only _ and _ can pass easily thru lipid bilayer
water and gases
94
in membranes passive diffusion is limited to _ molecules
lipid soluble
95
water soluble molecules require _ to cross membrane
carrier mediated transport
96
uniport is __
facilitated diffusion
97
respiratory alkalosis/acidosis prob is
respiratory
98
in metabolic acidosis ABG would be
low pH, because you are low on base,
99
why would you be lacking base?
sever diarrhea, aspirin overdose (early poisioning), lactic acidosis, ethylene glycol poisoning
Ketoacidosis: diabetes, alcoholism, fasting/starvation
100
why does diarrhea cause acidosis?
bc no time for bicarb to reabsorb bc losing it too fast
101
main reason for metabolic alkalosis
severe emesis (vomiting)
102
in metabolic alkalosis you have increased
pH and HCO3-
103
in metabolic acidosis you have decreased
pH and HCO3-
104
```
given:
pH = 7.31
Pa CO2 = 70mmHg
Pa O2 = 54mmHg
HCO3- = 34mEq/L
what type of acid base disturbance is this?
```
normal pH should be 7.35-7.45: so he is acidemia.
Pa (arterial) should be 40mmHg
Pa O2 should be 100mmHg
HCO3- = 22-26mEq/L
so we know it is acidosis by pH ==> now is it respiratory or metabolic?
CO2 + H20 ==>H2CO3==> H+ + HCO3-
the bicarb here is high. would a high bicarb cause the pH to go down? no. so it is not metabolic acidosis.
CO2 is high, that would cause the pH to drop so it is respiratory acidosis! the bicarb is high because the kidneys are trying to compensate
105
pH = 7.26
Pa CO2 = 26mmHg
HCO3- = 14 mEq/L
what type of disturbance?
CO2 + H20 H2CO3 H+ + HCO3-
pH is low = acidosis
low CO2 would not cause acidosis, so it is not respiratory
low bicarb would so it is the cause = metabolic acidosis
106
```
Blood pressure 90/40
pulse rate 130/min
respiration 32/min deep and rapid
pH - 7.22
PaCO2 = 20mmHg
PaO2 = 112mmHg
HCO3- = 8mEq/L
```
pH is low = acidosis
CO2 + H20 = H2CO3 = H+ + HCO3-
CO2 is low so that cant be the cause (rxn would shift left and soak up H+)
HCO3- is low so shift to the right = metabolic acidosis
107
```
pH = 7.1
PaCO2 = 78mmHg
PaO2 = 50mmHg
HCO3- = 27mEq/L
```
pH is low - acidosis
CO2 + H20 = H2CO3 = H+ + HCO3-
CO2 is high = pushed rxn to right = acidosis
108
carbaminohemoglobin
carbaminohemoglobin = a compound of haemoglobin and carbon dioxide = 10% of carbon dioxide is carried in blood this way (85% carried in blood as bicarbonate [hydrogen carbonate], 5% carried as free CO2, in solution
109
```
Denaturation usually destroys all the following except:
hydrogen bonds
covalent bonds
electrostatic bonds
hydrophobic bonds
```
covalent
110
the Michaelis menten constant is
Km
111
how does NaF inhibit glycolysis in bacteria?
Fluoride is a known competitor of enolase’s substrate 2-PG. The fluoride is part of a complex with magnesium and phosphate, which binds in the active site instead of 2-PG.[4] As such, drinking fluoridated water provides fluoride at a level that inhibits oral bacteria enolase activity without harming humans
112
what enzyme converts trypsinogen to trypsin
enterokinase
