Module 2: Water Flashcards
formula for Finding pH
pH= -log (H^+)
formula for finding pOH
pOH= -log (OH^-)
Formula for finding H^+
H^+= 10^-ph
Formula for finding OH^+
OH^-= 10^-ph
finding pH/pOH given one of them
pH= 14-pOH or pOH= 14-pH
organisms are __% to __% water
70% to 90% water
Normal metabolic activity can occur only when cells are at least ____ H2O
65%
water and its ionization products, ______ and ______, are critical determinants of the structure and function of many biomolecules.
- hydrogen ions
- hydroxide ions
What are the properties of water?
- Hydrogen bonding in water is key
to its properties. - Water forms H bonds with polar solutes
- Interactions with amphiphilic molecules
- Hydrophobic Interactions
- The solvent properties of water
derive from its polar nature
Because of its highly polar nature, water is an
excellent solvent for various compounds
THE SOLVENT PROPERTIES OF WATER DERIVE FROM
ITS POLAR NATURE
Water’s ability to surround ions in dipole interactions and diminish their attraction for each other
Water has a high dielectric constant
excellent solvent properties of water stem from its ability to readily form hydrogen bonds with the polar functional groups on these compounds, such as hydroxyls, amines, and carbonyls
Water Forms H Bonds with Polar Solutes
Water Forms H Bonds with Polar Solutes:
excellent solvent properties of water stem from its
ability to readily form hydrogen bonds with the polar functional groups on these compounds, such as ____, ___, and __
hydroxyls, amins and carbonyls
- apparent affinity of nonpolar structures for one another
Hydrophobic Interactions
Compounds containing both strongly polar and strongly nonpolar groups
Interaction with amphiphilic molecules
- the physical changes that result from adding solute to a solvent
- The presence of dissolved substances disturbs the structure of
liquid water, thereby changing its properties.
Colligative properties
Example of colligative properties (in water)
▪ Freezing point depression
▪ boiling point elevation
▪ vapor pressure lowering
▪ Osmotic pressure effects
- the freezing point of a solution is less than the freezing point of the pure solvent
- means that a solution must be cooled to a lower temperature than the pure solvent in order for freezing to occur.
- Freezing point depression
refers to the increase in the boiling point of a solvent upon the addition of a solute
Boiling point elevation
The vapor pressure of a pure solvent is greater than the vapor pressure of a solution containing a non volatile liquid. This lowered vapor pressure leads to boiling point elevation
Vapor pressure lowering
The pressure necessary to push water back through the membrane at a rate
exactly equaled by the water influx
Osmotic pressure solution
the minimum pressure that must be applied to a solution to halt the flow of solvent molecules through a semipermeable membrane
Osmotic pressure
a compound in which molecules of one component are physically trapped within the crystal structure of another.
- Cagelike
Clathrate
a proton is transferred from one water molecule to another to produce a hydronium ion (H₃O⁺) and a hydroxide ion (OH⁻)
Autoionization of water
Equilibrium expression for Autoionization of water
Kw = [H₃O⁺][OH⁻]
Equilibrium expression for Autoionization of water:
Kw
autoionization constant for water
a state in which opposing forces or influences are balanced.
Equilibrium
quantitative measure of the acidity or basicity of aqueous or other liquid solutions
pH
who devised pH scale?
Søren Sørensen, a danish biochemist
Acidic pH range
less than pH 7
Neutral pH range
pH 7
base/ basic pH range
greater than pH 7
Substances that are almost completely dissociated to form ions in solution
strong electrolytes
examples of electrolytes
salts such as NaCl and K2SO4,
strong acid such as HCl
strong bases such as NaOH
Proton acceptors
base
proton donors
Acids
Substances with only a slight tendency to dissociate to form ions in solution
weak electrolytes
are solutions that tend to resist changes in their pH as acid or base is added.
buffers
Buffer system is composed of;
- Weak acid and its conjugate base
serves to buffer the intracellular fluid of cells at physiological pH because pK2 lies near this pH value
Phosphate system
defined as a breathing rate more rapid than necessary for normal CO2 elimination from the body, can result in an inappropriately low [CO2(g)] in the blood.
Hyperventilation
is the opposite of hyperventilation and is characterized by an inability to excrete CO2 rapidly enough to meet
physiological needs.
Hypoventilation
Hypoventilation results in _____
respiratory acidosis
states that when equilibrium is disturbed, the rates of the forward and reverse reactions change to relieve that stress and reestablish
equilibrium.
Le Châtelier’s principle
proposed the first definition of
acids and bases
Svante Arrhenius
Defines acid as follows: “An acid is a hydrogen containing species that donates a proton.
A base is any substance that accepts a proton.”
Brønsted-Lowry Definition
theory stating that any compound that can transfer a proton to any other compound is an acid
Brønsted-Lowry theory
who revised Arrhenius’s acid-base theory
Johannes Brønsted and Thomas Lowry
- the act of making a substance neutral
- the reaction between an acid and a base, which produces a salt and water
Neutralization
a method or process of determining the concentration of a dissolved substance in terms of the smallest amount of reagent of known concentration required to bring about a given effect in reaction with a known volume of the test solution
titration
equation of neutralization
NaOH + HCl → H2O (water) and NaCl (salt)
First line of defense againts pH shift
Chemical buffer
Seconf line of defense againts pH shift
Physiological buffer
types of Chemical buffer system (in the body)
- Bicarbonate buffer
- Phosphate buffer
- Protein buffer
types of Physiological buffer
- Respiratory mechanism (CO2 excretion)
- Renal mechanism (H+ excretion)
maintaining the pH homeostasis of blood
Bicarbonate buffer system
free and terminal amino acids
– Respond to pH changes by accepting or releasing H+
Protein buffer; Amino acids
- Binds CO2
- Binds and transports hydrogen and oxygen
- Maintains blood pH as hemoglobin changes from oxyhemoglobin to
deoxyhemoglobin
Protein buffer; Hemoglobin
how does bicarbonate buffer lowers pH
- lowers pH by releasing H+
- raises pH by binding H+
how does bicarbonate function with respiratory and urinary systems?
– to lower pH, kidneys excrete HCO3
– to raise pH, kidneys excrete H+ and lungs excrete CO2
consists of acidic phosphate ions and alkaline phosphate ions that work to neutralize pH
Phosphate buffer
a description of the process wherein protein compounds consume small amounts of acids or bases.
Protein buffers
is a substance that when placed in water increases the hydrogen ion concentration
Arrhenius acid
is a substance that donates a proton.
Bronsted-Lowry acid
is a substance that serves as an electron pair acceptor
Lewis acid
an example of a arrhenius, Bronsted-Lowry, and Lewis acid.
Carbonic acid
Physiological buffer systems (in the body parts)
- lungs
- kidneys
-Provide O2 to cells and remove CO2
- Exhalation of carbon dioxide
Respiratory regulation
- Can eliminate large amounts of fixed acid
- If kidneys fail, pH balance fails
- Can conserve and produce bicarbonate ions
Renal Regulation
- Only regulated by the kidney.
- Primary base in the body is HCO3
- The kidney can retain or excrete HCO3 as needed
Base excretion
involves the enzyme carbonate
dehydratase (carbonic anhydrase)
Renal carbonate regeneration
Renal Renal carbonate regeneration involves the enzyme _______ _____ (_______ ______)
- carbonate dehydratase
- (carbonic anhydrase)
3 responses of renal regulaion in acidosis
A. increased reabsorption of the filtered HCO3^-
B. increased excretion of titratable acids, and
C. increased production of ammonia
an abnormal pathophysiological condition characterized by the buildup of excess base or alkali in the body
Alkalosis
- ## occurs when acid builds up or when bicarbonate (a base) is lost
Acidosis
