Class 3 - Molecular Interactions Flashcards
What are the main functions of water?
Dissolve and transport compounds in blood, provides medium for movement of molecules into and throughout cells, participates in chem reactions, most compounds must interact with water
Where do hydrogen bonds form in water molecules?
Dipole rich end of H attracts (Hydrogen bonds) dipole neg end of O.
One oxygen can bind covalent to 2 hydrogens and hydrogen bond with another hydrogen.
One hydrogen atom can covalent bond with 1 oxygen and hydrogen bond with 1 oxygen
How much of our body contains water? (newborm, adult male, adult female)?
newborns have 80%, adults males have 60% and adult females have 50%
How does water dissolve crystalline salts?
Water hydrates their component ions. The NaCl crystal lattice is disrupted as water molecules that cluster about the Cl- and Na+ ions. The ionic charges are partially neutralized, and the electrostatic attractions necessary for lattice formation are weakened
In Na+ ion the neg oxygen is attracted to pos ion. In Cl- ion the pos hydrogen is attracted to neg ion.
What is the structure of fatty acid chains?
fatty acid chains have hydrophobic alkyl chains each surrounded by highly ordered water molecules. These fatty acids also have a hydrophilic head and are amphipathic
What do lipids force water molecules to do (dispersion)?
Each lipid molecule forces surrounding H20 molecules to become highly ordered
What are the structures of lipid clusters and micelles?
only lipid portions at edge of cluster force ordering of water - fewer H20 molecules are ordered and entropy is increased
micelles - hydrophobic group sequestered from water and ordered shell of H20 molecules is minimized to increase entropy
What do hydration shells have to do with biomolecules?
the structure and function of biomolecules are strongly influenced by their hydration shells
What is the equation for the dissociation of water?
Remember that H+ = H30+
What is the range of ph scale (acidic, neutral, alkaline)? What does 7 ph neutral mean? Which end has more H+?
pH range: acidic (0-7 with high H+) neutral (7) alkaline (7-14 with low H+)
neutral pH is at 7 because it is the absolute value of the ion product of water at 25 degrees Celsius
H+ concentration and pH number are inverse related
What are acids and bases? What are conjugate acids and bases?
Acids are the compounds that DONATE H+
Bases are compounds that ACCEPT H+
Conjugate Acids are substance formed when base accepts a H+ [looks like former base – opposite to A]
Conjugate bases are substance formed when acid looses a H+ [looks like former acid – opposite to B]
What is the difference between strong and weak acid
Strong acids have mostly ions in solution, therefore the bonds holding H and A together must be weak. Strong acids easily break apart into ions ==> COMPLETELY DISSOCIATE IN AQ SOLUTION
Weak acids exist mostly as molecules with only a few ions in solution, therefore the bonds holding H and A together must be strong
PARTIALLY DISSOCIATE IN AQ SOLUTION
What is the relevance of acid in metabolism?
During metabolism body produces many acids that alter pH of blood and other body fluids
metabolism produces a large amount of acid per day
body manages acid by buffers!
What is a buffer?
A buffer is a combination of weak acid and its conjugate base which causes the solution to resist changes in pH when H+ or OH- ions are added
pka = pH at which 50% dissociation occurs
What are the ranges of blood pH?
6-7 Death
7-7.35 Acidosis
7.35-7.45 Normal
7.45 - 7.8 Alkalosis
7.8 to 9 Death
What is the equation for the bicarbonate buffering system? Where do the components come from?
CO2 is from the TCA cycle and is main source of metabolic acid
carbonic anhydrase catalyzes reaction of C02 to carbonic acid within red blood cells
CO2 dissolves in water producing carbonic acid (WEAK)
Carbonic acid partially dissolves into bicarbonate and H+ (WEAK)
_______________
Carbonic acid is buffered by Hemoglobin (Hb) and phosphate (HPO4 2-) in red blood cells
In bicarbonate system what are hepatic cells, blood, red blood cells producing?
What happens if blood is too acidic (add H+ and low pH)? Describe lungs, kidney, blood response
INCREASED Respiration rate increases to DECREASE C02 (by expelling it). DECREASING reactants shifts equation to LEFT to reactants and consumes/decreases H+
Less carbonic acid produced which means less H+ dissociating
Kidneys increase reabsorption (IN) of bicarbonate
Blood pH increases (making H+ decrease)
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bicarbonate reserve in the body is lowered by retaining bicarbonate and more bicarbonate leaves kidneys
What buffering happens in lumen of proximal tube versus proximal tube cell
lumen of proximal tube
bicarbonate and H+ –> H2C03
carbonic anhydrase –> H2O + Co2
proximal tube cell
C02 + H20 –> H2Co3
H2Co3 –> H+ + HCO3-
bloodstream
bicarbonate enters
What are ketone bodies?
ketone bodies are naturally produced during fatty acid metabolism
ketone bodies are weak acids that partially dissociate –> increase H+ in blood and interstitial fluid
bicarbonate buffers it
