Chemistry of Water Flashcards
how many hydrogen bonds does each water molecule form with others
Each water molecule
forms hydrogen
bonds with 4 others
what is the pH range for cell survival?
between 6.8 and 7.8
what molecule gives up H+ when ionized?
an acid
what is an example of a strong acid
HCL
what molecule gives up OH-
a base
what is an example of a strong base?
NaOH
True or False. A weak acid will only partially ionize when added to water
true
a species gains a proton (H+)
Protonation
a species loses a proton
deprotonation
T or F. The Henderson-Hasselbach equation only applies to weak acids or
bases
True
when will something buffer best?
1.0 pH units above and below the pKa
At a pH of 6.74 for acetic acid what is the ratio of salt/acid?
2=log(d/p)
2= log(20/1)
ratio is 20:1
At a pH of 3.74 for acetic acid what is the ratio of salt/acid?
-1=log(d/p)
-1= log(1/10)
ratio is 1/10
What is the intracellular buffer system?
Phosphate buffer system
What is the RBC buffer system?
Hb buffer system
What is the intracellular and plasma buffer system?
Proteins
What is the extracellular fluid buffer system?
bicarbonate-carbonic acid buffer
system
what form of phosphate is the best for intracellular?
H2PO4- + H+ and HPO42- + H+
Phosphates pka is about 7.2 for these forms
Unusual properties of water
- high surface tension
- highest density at 4 C
- high heat capacity
- high heat of vaporization
- excellent solvent
- ionizes
solvent
a liquid substance capable of dissolving other substances
- usually water
pH scale
measures the amount of H+ ions in a solution
acids
everything below a 7 on the pH
- they have more H+
- have few hydroxide ions (OH-)
bases
everything above a 7 on the pH scale
- they have fewer hydrogens ion
- lots of OH-
mixtures that can react with acids or bases to keep the pH within a particular range
a buffer
enzyme that catalyzes the reaction between carbon dioxide and water to form carbonic acid
carbonic anhydrase
carbonic acid is a _____ so it ionizes to form ______
carbonic acid is a weak acid so it ionizes to form bicarbonate
Your blood brings bicarbonate to your lungs and it is exhaled as ______
carbon dioxide
How is bicarbonate formed?
CO2 + H2O -> (carbonic anhydrase) -> HCO3- + H+
carbonic acid (pronated) dissociates into bicarbonate (deprotonated) and H+
solute
a substance that dissolves
- ions, molecules, atoms
BICARBONATE-CARBONIC ACID has a pka of
6.1
- it will best buffer at 5.1 and 7.1
what is the pH of blood?
7.4
When _____ is produced as a result of fuel oxidation it will
dissolve and be converted to _______ by carbonic anhydrase in the red blood cell. _______ will ionize and be exported in the plasma via the ______.
When CO2 is produced as a result of fuel oxidation it will
dissolve and be converted to H2CO3 by carbonic anhydrase in the red blood cell. H2CO3 will ionize and be exported in the plasma via the HCO3-/Cl transporter
With hyperventilation, the blood pH increases. Why?
When a person hyperventilates they exhale more carbon dioxide than normal. As a result, the carbon dioxide concentration in the blood is reduced and the bicarbonate/carbonic acid equilibrium shifts to the left
Increase in pH = fewer hydrogen ions
How does low pH affect cells?
Not only do changes in pH alter the way in which cells metabolize and grow, it can also change the physical structure of the cells themselves.
AND SHAPE IS EVERYTHING
