Biochem Ex 1 - Hydrophilic, Buffer Flashcards Preview

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Flashcards in Biochem Ex 1 - Hydrophilic, Buffer Deck (16)

Is cocaine a vasoconstrictor?



Is cocaine polar or non-polar?



What happens to cocaine in an acid environment?

In an acid environment where there are more hydrogens present, hydrogen gets pushed into the cocaine molecule (gets protonated) giving it the acid form to the right


Are basic molecules polar or non-polar?



How does cocaine get inside the body?

Cocaine has to pass the lipid barrier (found on membranes) to get into the blood. In its polar form, it cannot get through the barrier so it gets converted to the non-polar form, which can then pass to the blood.  It does so with the hydrophobic effect. But the acid form (protonated form) is the one that can carry out the actions we want, so it has to be converted again once inside the body.


Why do lipid molecules come together in water?

There is less surface area wet so there is more random water around the molecule (more entropy). Nature loves randomness (entropy), so this is a more favored state (the hydrophobic molecule being close together). So likes-like-like.


How does pH affect absorption?

Acidic drug: If in an acidic medium the acid will withdraw protons from the acidic drug and cause it to unionize so it will go through the membrane better

Basic drug: If in an acidic medium the acid will add protons to the basic drug making it ionized and more difficult to absorb


What is the Henderson-Hasselbalch equation?

ph = pKa + log( [conj base] / [acid] )


What is pKa?

pKa is equal to the pH at which the two forms are equal.


Calculate the pKa:



Draw a titration curve for the below:


What is the most important buffer system in the body and blood?

Bicarbonate buffer system


What is the second most important buffer system in the body?

Protein buffer system


Where is the protein buffer system more important and where is it less important?

More important intracellularly since there are more proteins in cells. Less important extracellularly.


Which is the least important buffer system in the body?

Phosphate buffer system. DNA, nucleotides carry phosphate and buffer as well. Less important


What pH the compartment of the body is in affects the hydrophobicity of the drug.


Something with _____ pKa can hang on to the hydrogen at a lower pH.

a) low

b) high