Download Explain hyperventilation and hypoventilation in terms of

Cell Biology & Physiology
Lecture 1:
1. Concept of lifeless molecules making up living organisms:
a. Atoms such as C, N, O, and H, P, S are lifeless and organized by covalent bonds
into biomolecules (nucleotides, amino acids, carbohydrates, lipids).
b. Biomolecules makeup macromolecules (DNA, RNA, proteins, polysaccharides,
and membranes).
c. These organize into cells—systems—form life.
2. Tremendous diversity in the combination of basic biomolecules (nucleotides, amino
acids, carbs, and lipids) provides distinctions between living systems.
a. Through electron-sharing in covalent bonds, H O C N combine to create life.
Simple molecules combine to form complicated linear molecules, then build
hydrophobic and hydrophilic molecules like fatty acids and nucleic acids.
b. The same atoms and molecules make up every living thing, but the combos are
different.
c. There are infinite combinations: 5 nucleotides—DNA and RNA—20 amino
acids—proteins
3. Concept of energy transformation and equilibrium:
a. Energy transformations: energy from environment, change and expend it. Many
forms of energy
i. Potential energy (nutrients and sunlight)energy transduction (chem
and cell work)entropy increased (CO2, H2O and heat given off)
ii. Exchange of ATP and ADP
b. Energy equilibrium: our bodies work to establish equilibrium within ourselves,
but we are never at equilibrium with our surroundings. Only in death do we
reach equilibrium with our surroundings. Our components are recycled into the
environment.
4. Relationship between structure and function
a. Amino acid sequence determines protein structure and function
b. How they look determines how they function
c. Fatty acids, triacylglycerol and lipids: fuel storage and membranes
d. Carbohydrates: fuel source, storage, structure
e. Amino acids: metabolites, proteins
f. Nucleotides and nucleic acids: high energy, DNA, RNA
5. Pathways and Mechanisms
a. Complex goals require complex pathways
b. Pathways of glycolysis and gluconeogenesis
c. Disease occurs when complex pathways are interrupted or go astray
i. Ex: DNA not replicated properly
ii. Ex: ions go out of balance with cells
iii. Ex: improper nutritionlack of “building blocks”
Lecture 2 : Acids, Bases and Buffers
1. Relationship between the structural features of water and its unique chemical
properties:
a. Features: Water (H2O) has a bent structure, which makes it polar. It is a H bond
donor and acceptor. It has the potential to form four H bonds per water, but
liquid water averages only 2.3 H bonds. (We don’t need to know bond angles or
lengths!)
b. Chemical Properties: The dipolar nature of water allows it to from hydrogen
bonds and act as a solvent. Its chemical properties allow its resistance to
temperature changes. Its heat of fusion is high and a large drop in temperature
is required to convert it to ice. Thermal conductivity is high and facilitates heat
dissipation from high-energy use areas such as the brain into the blood and into
the total body water pool. Evaporation from the skin cools the body.
2. Hydration Cell Definition and its Interactions that make it possible:
a. Hydration Cell: Solutes are surrounded by water molecules and dissolved. Ions
are always hydrated in water and carry around a hydration cell. Water forms H
bonds with polar solutes. Hydration shells surround both cations and anions.
The partial negative or the partial positive of water is attracted to the cation or
anion, respectively.
b. This process occurs with water (a polar solvent) and polar solute.
c. Hydrophobic: water hating
d. Hydrophilic: water loving
3. Interaction of water with a non-polar, or hydrophobic, substance and why this leads to a
decrease in entropy:
a. Interaction: A nonpolar solute “organizes” water. The H bond network of water
reorganizes to accommodate the nonpolar solute. This is an increase in the
“order” of water.
b. Entropy: Because water increases the order (and decreases the randomness),
there is a decrease in entropy. This is important because molecules can have
both hydrophilic and hydrophobic properties. It determines how they act,
where they are located, and how they function, in the blood. It all goes back to
the thermodynamics.
c. The system wants to have the highest entropy possible or the most disorder,
that’s why water forms hydration cells around ions rather than the ionic
compound as a whole!
4. Structural characteristics of amphipathic/amphiphilic molecules
a. Amphiphilic/Amphipathic molecules contain both polar and nonpolar groups.
They associate with molecules that are attracted to both polar and nonpolar
environments.
b. The nonpolar, hydrophobic part of the molecule faces inward away from water.
The polar, charged part of molecule faces outward toward water. The water
forms favorable dipole interactions with polar surface.
c. Example: Fatty Acids. The sodium salt of palmitic acid (a fatty acid) that has a
polar head (Na+ -O2C--) and a nonpolar tail (-CH2)14CH3
5. Ionization of water and how the equilibrium constants for water dissociation are related
a. H2O ionizes (dissociates) into H+ and OHb. The equilibrium constant for water is the formula:
i.
ii. The production of H and OH by the dissociation of water does not
significantly change the concentration of H20. Therefore H2O can be
considered a constant and grouped together Keq which is also a
constant. This makes dealing with H+ and OH- much easier.
iii. [HOH]=55.5M
iv. [H]=[OH]=1*10^-7 M
v. Keq= 1.8*10^-16 M
vi. Kw=Keq*55.5=1*10^-14M
6. pH and the relationship between pH and [H+]
a. pH=-log[H+]
b. pOH=-log[OH-]
c. pH=-log[1*10^-7)=7
d. we won’t use logs very much, only a few simple problems on the test
7. Log10 functions
a. Rule: log10(10x)=x
8. Acid Dissociation of a weak acid and what information the equilibrium constant provides
i.
ii. The dissociation constant is the product of the ions divided by the
concentration of the acid.
iii. The Henderson-Hasselbach Equation, for any acid HA, describes the
relationship between the pKa and the concentrations existing at
equilibrium and the solution pH
b. pH=pKa + log([A-]/[HA])
9. Henderson-Hasselbach equation
a. See above
Lecture 2
Explain a titration curve and tell what information it provides about Ka and the
relative amounts of HA, A-, and H+
The curve shows the change in pH as base is added in order to remove a proton from a
acid and form its conjugate base. The plot of pH versus base added is flat near the pKa
this is where the pH= pKa and [HA] = [A-]. Prior to the midpoint the concentration of
[HA] > [A-] and the pH is lower ([H+] higher) than the pKa. After the midpoint the
concentration of [A-] > [HA] and the pH is above ([H+] lower) the pKa.
Define the bicarbonate buffer system and write out the three coupled equilibria of
the bicarbonate buffer system
A buffer is a solution containing substances which have the ability to minimize
changes in pH when an acid or base is added to it
– Most buffers consist of a weak acid and its conjugate base
H2CO3: weak acid and HCO3- : conjugate base
– Buffer gives or receives protons to keep solution pH stable
The bicarbonate buffer system is
CO2 (gas)  CO2 (dissolved)
CO2 (dissolved) + H2O  H2CO3 rxn accelerated by carbonic anhydrase
H2CO3 [H+] + HCO3The major source of metabolic acid in the body is CO2 – primarily from fuel
oxidation through the TCA cycle
CO2 dissolve in H2O to produce carbonic acid or H2CO3
Carbonic acid is both the major acid produce by the body as well as its own buffer
Explain how the bicarbonate buffer system responds to increases in [H+] or CO2
-Increase in [H+]:
An increase in H+ leads to an increase in carbonic acid production. This also
leads to an increase in CO2 and H2O production to break down the excess carbonic acid.
-Increase in CO2:
An increase in CO2 leads to an increase in carbonic acid production. This also
leads to an increase in [H+] and HCO3- production to remove the excess carbonic acid.
Explain hyperventilation and hypoventilation in terms of the bicarbonate buffer
system
CO2 (gas)  CO2 (dissolved)
CO2 (dissolved) + H2O  H2CO3
H2CO3 H+ + HCO3-
-Hyperventilation:
Breathing too fast results in too much CO2 being expelled per breath. This causes
CO2 levels to drop. This forces a shift in equilibrium causing the carbonic acid (H2 CO3)
to be broken down into CO2 and H2 O. This in turn forces the H+ and bicarbonate ion
(HCO3 ) to produce more carbonic acid resulting in a blood [H+ ] drop and pH increase
causing respiratory alkalosis.
-Hypoventilation:
Breathing too shallow or slow to expel enough CO2 causes an increase in CO2
levels. This forces a shift in equilibrium causing more carbonic acid (H2 CO3) to be made
to remove the excess CO2. This in turn forces the carbonic acid (H2 CO3) to be broken
down into H+ and bicarbonate ion (HCO3 ) resulting in a blood [H+ ] increase and pH
decrease causing respiratory acidosis.