- WELCOME TO PART 8 IN THE ACID BASE TUTORIAL SERIES.
THIS WILL FOCUS ON THE PHYSIOLOGICAL EFFECTS OF PH
ON THE FUNCTIONAL GROUPS WE'RE LEARNING ABOUT.
LET'S GET STARTED.
ALL RIGHTY. SO CELLULAR PH, IS GOING TO BE PH 7.4.
SO, THIS PH IS FOR CARBOXYLIC ACIDS AND AMINES.
THIS PH IS SLIGHTLY BASIC.
THIS PH CREATES A SLIGHTLY BASIC ENVIRONMENT.
SO EVERYTHING IN CHEMISTRY IS RELATIVE THOUGH.
SO FOR AMINES THOUGH, BECAUSE AMINES ARE WEAK BASES,
SO PH 7.44 AMINES IS SLIGHTLY ACIDIC.
LET ME SEE. OKAY.
SO, CELLULAR PH DOESN'T CHANGE, IT'S 7.4.
BUT THAT ENVIRONMENT, DIFFERENT FUNCTIONAL GROUPS
EXPERIENCE THAT ENVIRONMENT DIFFERENTLY.
AND SO, WHENEVER WE'RE LOOKING AT REACTIONS OCCURRING,
AT CELLULAR PH OR PHYSIOLOGICAL PH,
WE NEED TO BE AWARE OF THIS IMPORTANT ACID, BASE CHEMISTRY.
SO LET'S TAKE A CLOSER LOOK.
SO FIRST WE'LL FOCUS ON THE CARBOXYLIC ACIDS
AND THE ESTERS, RIGHT?
THESE ARE WEAK ACIDS.
SO, PH 7.4 IS SLIGHTLY BASIC FOR THEM.
SO WE'VE LEARNED ABOUT OUR CARBOXYLIC ACIDS
HAVING THIS FORM HERE AND OUR PHOSPHATE ESTERS ARE HERE.
SO, BECAUSE THESE ARE WEAK ACIDS AND PHYSIOLOGICAL PH 7.4
IS SLIGHTLY BASIC,
THE CARBOXYLIC ACIDS AND THE PHOSPHATE ESTERS
LOSE THESE PROTONS. LOSE H+. HERE AND HERE.
BUT REMEMBER THAT THEY'RE WEAK SO IT'S ALWAYS AT EQUILIBRIUM.
BUT THE CONVENTION WHEN WE LOOK AT MOLECULES
IN A BIOCHEMICAL CONTEXT IS WHEN WE SEE A CARBOXYLIC ACID,
WE'LL SEE IT DRAWN AS THE CARBOXYLATE.
AND WHEN WE HAVE A PHOSPHATE ESTER, WE'LL SEE IT DRAWN
AS THE ORGANIC PHOSPHATE.
SO THIS IS HOW YOU'LL SEE THEM WHEN THEY'RE DRAWN
AT PHYSIOLOGICAL PH.
AMINES ON THE OTHER HAND ARE WEAK BASES.
SO,PH 7.4 IS A SLIGHTLY ACIDIC ENVIRONMENT.
SO IF WE LOOK AT OUR AMINES, WE TEND TO THINK ABOUT THEM
IN THEIR NEUTRAL FORM.
HOWEVER, THEY BECOME PROTONATED AT PHYSIOLOGICAL PH
AND SO WE'LL DRAW IT, RIGHT?
SO, THERE'S THE H+, RIGHT,
THAT LONE PAIR ON THE NITROGEN FORMS A BOND WITH THE PROTONS
FLOATING AROUND.
AND THE OTHER WAY TO DRAW THIS WOULD SIMPLY BE THIS WAY.
SO, AT PHYSIOLOGICAL PH, WE WILL EXPECT TO SEE
THE CARBOXYLATE AND PHOSPHATE ESTERS AS ANIONS.
AND WE WILL SEE AMINES AS AMMONIUM IONS.
MAKE SURE, RIGHT, TO DISTINGUISH BETWEEN AMINES AND AMIDES,
SO THESE ARE THE ONLY THREE GROUPS WHERE WE HAVE TO WORRY
ABOUT THE CELLULAR EFFECTS OF PHYSIOLOGICAL PH.
AND THEN WHY IS THIS IMPORTANT?
WELL, THE IONIZED FORMS ARE IMPORTANT TO OUR HEALTH
BECAUSE THE CHARGES ENABLE THIS GROUP TO BIND THE ENZYMES,
CHEMICALLY REACT,
OR THE CHARGE ENABLES THEM TO STAY INSIDE THE CELL
BECAUSE THE CELL MEMBRANES ARE NONPOLAR.
I JUST WANT TO GIVE YOU A CONTEXT FOR WHERE THIS KNOWLEDGE
WILL BE USEFUL TO APPLY AS WISDOM.
AND THEN JUST ADDITIONALLY MANY MEDICAL CONDITIONS,
KIDNEY DISEASE, STROKE, EXPOSURE TO POISONS
CAN RAISE OR LOWER THE PH WITHIN THE CELL
AND SO NOW WE CAN RECOGNIZE IT.
AND IF WE HAVE CHANGES IN THE PH THAT CAN DISRUPT
THE CELL FUNCTION BY CAUSING THESE KEY MOLECULES
OR KEY FUNCTIONAL GROUPS WITHIN THE MOLECULES
TO CHANGE FROM THEIR NEUTRAL TO THEIR IONIZED STATE
OR VICE VERSA.
ALL RIGHTY. SO THAT CONCLUDES THIS BRIEF TUTORIAL
ON THE EFFECTS OF PHYSIOLOGICAL PH
ON SOME KEY FUNCTIONAL GROUPS.
PLEASE TAKE SOME TIME NOW TO WORK A FEW HOMEWORK PROBLEMS
TO REINFORCE YOUR UNDERSTANDING.