7.2 Protein: Protein Functions

7.2 Protein: Protein Functions


– WELCOME TO THE SECOND SECTION
ON PROTEIN. THIS SECTION IS
COVERING FUNCTIONS OF PROTEIN. PROTEINS HELP
WITH ACID-BASE BALANCE. THE PH AT THE BLOODSTREAM IS
ACTUALLY KEPT AT A– UNDER VERY TIGHT CONTROL AND
PROTEINS HELP WITH THIS CONTROL. WE PROTECT OURSELVES
FROM INFECTION IN PART WITH ANTIBODIES,
AND ANTIBODIES ARE PROTEINS. WE LEARNED A LITTLE
ABOUT BLOOD CLOTTING PROTEINS IN CHAPTER 8,
AND WHEN WE COVERED– WELL, CHAPTER 7 AND CHAPTER 8
WHEN WE COVERED VITAMIN K-1. ENZYMES.
WE ALSO TALKED ABOUT THESE DURING CHAPTER 7,
AND ENZYMES ARE CATALYST. THEY HELP MAKE REACTIONS HAPPEN. AND THERE ARE MANY
REACTIONS THAT HAPPEN THROUGHOUT THE BODY
EVERY SINGLE DAY, AND ENZYMES ARE AN EXTREMELY,
EXTREMELY, IMPORTANT PART OF OUR
DAILY FUNCTIONING. AND PROTEINS ARE ENZYMES,
AND WE’LL COME BACK TO THIS, AND WE’LL GO OVER IT
MORE DETAIL IN A MINUTE. SOME PROTEINS– SOME HORMONES ARE PROTEINS. SOME ARE STEROLS. THE HORMONE, FOR EXAMPLE,
INSULIN IS A PROTEIN. AN EXAMPLE OF A TRANSPORT
PROTEIN WOULD BE HEMOGLOBIN. WHAT DOES HEMOGLOBIN TRANSPORT? IT TRANSPORTS OXYGEN. SO PROTEINS ARE
REALLY IMPORTANT, HAVE REALLY IMPORTANT FUNCTIONS
AS FAR AS TRANSPORTING, TRANSPORTATION, TRANSPORTING,
FOR EXAMPLE, OXYGEN THROUGHOUT THE BODY. STRUCTURES, IF YOU THINK ABOUT– MOST OF THE BODY
STRUCTURE THAT YOU CAN SEE OR THAT
YOU HAVE HEARD OF, IF YOU LOOK DOWN AT YOUR
SKIN AND WHAT DO YOU SEE? YOU’RE ACTUALLY
LOOKING AT COLLAGEN. COLLAGEN IS A PROTEIN. YOUR BONE IS MADE UP OF
PROTEIN WITH CARTILAGE, YOUR TENDON, YOUR LIGAMENT,
YOUR MUSCLE. SO MANY OF THESE STRUCTURAL
COMPONENTS OF YOUR BODY ARE MADE UP OF PROTEIN,
AND THEY’RE NOT STATIC. THEY’RE CONSTANTLY
CHANGING [INAUDIBLE], MEANING THEY ARE
BEING BROKEN DOWN AND BEING BUILT
BACK UP ALL THE TIME. SO THERE IS A NEED FOR PROTEIN
TO BE MADE FOR THIS FUNCTION. LASTLY IS ENERGY. AND THIS IS ONLY IF NECESSARY. WE DON’T USE PROTEIN FOR
ENERGY TO A GREAT EXTENT. I’M GOING TO TALK A
LITTLE BIT ABOUT ENZYMES, AND WE’RE GOING TO GO INTO
DIGESTION AND ABSORPTION NEXT, BUT EACH OF THESE
ARE AMINO ACIDS, AND THIS IS A POLYPEPTIDE CHAIN. SO IT’S A– ESSENTIALLY A SHORT,
PRIMARY STRUCTURE OF PROTEIN. THIS IS THE INTESTINES,
AND ENZYMES, WHICH ARE RELEASED
FROM BOTH THE PANCREAS AND THE INTESTINAL [INAUDIBLE], BREAKDOWN THESE
LONG CHAINS OF AMINO ACIDS INTO DIPEPTIDES
AND TRIPEPTIDES, SO THESE SMALL TWO AND THREE
UNIT AMINO ACID UNITS AND THEN SINGLE AMINO ACIDS
BEFORE THEY ARE ABSORBED. SO THIS IS AN EXAMPLE OF HOW
ENZYMES WORK IN DIGESTION. AND I WANT TO POINT OUT THAT THE VERY COMPLEX STRUCTURE
OF A PROTEIN, WHICH IS THAT
QUATERNARY STRUCTURE, ENDS UP BEING UNFOLDING AND
UNCOILING IN THE STOMACH. SO AS WE EAT IT GOES
DOWN TO THE STOMACH BECAUSE OF THE LOW
PH IN THE STOMACH. WE LEARNED THIS
EARLIER THIS SEMESTER. THOSE PROTEINS, LITERALLY,
THEY’RE UNCOILED. THEY’RE UNFOLDED AND THAT’S IN
THE STOMACH BECAUSE OF THE PH. THIS IS CALLED A DENATURATION. AND PROTEINS CAN BE
DENATURED BY ACIDS, LIKE THE STOMACH ACID BASES, HEAT WHEN YOU COOK,
OR HEAVY METALS. NOW HERE’S AN EXAMPLE
OF GOING FROM THAT VERY COMPLEX STRUCTURE TO
THAT POLYPEPTIDE CHAIN. NOW THIS IS IMPORTANT BECAUSE
WHEN WE THINK ABOUT SOME OF THE, FOR EXAMPLE,
ENZYMES YOU MIGHT TAKE, YOU HAVE TO THINK ABOUT
WHETHER THESE ARE GOING TO BE FUNCTIONING ONCE THEY
REACH THE INTESTINES. THE EXAMPLE IS LACTASE. LACTASE IS THE ENZYME
THAT BREAKS DOWN LACTOSE. REMEMBER CHAPTER 4,
LACTOSE IS THE LACTOSE AND GLUCOSE,
AND IT’S MILK SUGAR. SOME PEOPLE DON’T HAVE
THE ENZYME TO BREAK THIS DOWN SO THEY WILL
EITHER TAKE AN ENZYME OR DRINK A LACTAID THAT
HAS LACTASE IN IT. AND MOST PEOPLE TELL
THAT IT WORKS SO, SO. AND HERE’S THE REASON WHY. WHEN YOU TAKE THAT LACTASE, IT GETS INTO THE STOMACH,
RIGHT IN HERE, THAT LOW ACIDITY AND
THERE IS A PH OF 2, IT’S VERY ACIDIC,
IT’S GOING TO UNCOIL THAT LACTASE SO IT DOES HAVE A
CHANCE TO ACT BEFORE THAT ACID HAS A CHANCE TO COMPLETELY
UNFOLD AND UNCOIL THE ENZYME. IT DOES HAVE A
CHANCE TO WORK AND BREAKDOWN SOME OF THAT LACTOSE. SO MOST PEOPLE TELL
YOU, WELL, IT WORKS FAIRLY WELL,
BUT NOT COMPLETELY. IT EVENTUALLY UNCOILS. IT GOES FROM A STRUCTURE LIKE
THIS TO A STRUCTURE LIKE THAT. AND REMEMBER THE SHAPE OF THE
PROTEIN DETERMINES ITS FUNCTION, AND IT CANNOT FUNCTION WHEN
IT’S JUST IN THIS STRING. AND THEN THIS STRING IS GOING TO
END UP IN THE INTESTINES, AND THEY WILL BE DIGESTED
AS ANY OTHER PROTEIN WOULD. THEN I MENTIONED
THE RAW FOOD DIET BECAUSE IT IS FAIRLY POPULAR, AND PROPONENTS OF THE RAW
FOOD DIET WILL TELL YOU THAT THERE ARE ENZYMES THAT
NATURALLY OCCUR IN FOOD, WHICH THERE ARE, BUT THEY
ARE NECESSARY FOR DIGESTION. AND IF WE DON’T
COOK THESE ENZYMES, BECAUSE REMEMBER
HEAT IS SOMETHING THAT WILL DENATURE PROTEIN, MEANING THAT IT UNCOILS,
UNFOLDS IT, WHEN YOU CONSUME
THOSE THEY HELP WITH DIGESTION AND ARE
NECESSARY FOR DIGESTION. AND THERE ARE TWO PROBLEMS
WITH THIS ARGUMENT. ONE IS THAT MANY OF
THE ENZYMES CAN BE DENATURED BY STOMACH
ACID AS WELL. IT IS TRUE WHEN YOU– PROTEIN WILL BE
DENATURED BY HEAT, AND YOU CAN SEE THESE CHANGES. AND IT GOES THAT
CLEAR [INAUDIBLE] LOOK TO A SOLID
AND A FIRM WHITE. WELL, THAT IS A
DENATURATION OF PROTEIN. SO HEAT WILL DO THAT. ACID WILL DO SOMETHING SIMILAR. AGAIN, IT’S GOING TO
UNCOIL AND UNFOLD AND THOSE ENZYMES
WILL NO LONGER WORK. NOW THERE IS [INAUDIBLE]
BECAUSE THERE ARE SOME PLANTS– ACID STABLE PLANT’S
ENZYMES THAT OCCUR IN FOOD, AND THEY ACTUALLY MAKE IT
THROUGH ALL THE PROCESS OF DIGESTION AND MAY
STILL BE ABLE TO WORK. WE STILL HAVE A LOT OF
EVIDENCE THAT THEY’RE ACTUALLY NECESSARY FOR DIGESTION,
THAT THE BODY’S ENZYMES CAN ACTUALLY DO ALL THE
DIGESTIVE [INAUDIBLE]. NOW I’M NOT SAYING
DO NOT EAT RAW FOOD, AND I’M DEFINITELY NOT
SAYING DON’T EAT RAW FRUITS AND VEGETABLES
BECAUSE I ABSOLUTELY, WHOLEHEARTEDLY AGREE THAT
YOU SHOULD EAT AN ABUNDANCE OF RAW FOODS AND VEGETABLES,
ABSOLUTELY. BUT COOKING A LOT OF FOODS DOES
HELP DESTROY MICROORGANISMS, WHICH LEAD TO FOOD POISONING,
AND WE’LL TALK TO THAT LATER– TALK ABOUT THAT
LATER THIS SEMESTER. SO THAT IS ONE RISK. THERE ARE SOME NUTRIENTS,
SUCH AS PHYTOCHEMICALS, THE CAROTENOIDS, WHICH
ACTUALLY BECOME MORE [INAUDIBLE] AVAILABLE
WHEN YOU COOK THEM. SO BETA-CAROTENE IS GOOD
EXAMPLE AND TOMATOES. AND WE TALKED ABOUT THIS
EARLIER THIS SEMESTER. MY ADVICE TO YOU IS THAT,
ABSOLUTELY, EAT RAW PLANT FOOD,
RAW FRUITS AND VEGETABLES, BUT IT’S ALSO OKAY TO COOK THEM. AND IF YOU ARE EATING ANY SORT
OF MEAT OR ANYTHING THAT MIGHT BE CONTAMINATED BY BACTERIA YOU
ABSOLUTELY HAVE TO [INAUDIBLE]. IT’S BETTER TO BE
ON THE SAFE SIDE. NOW THE OTHER FUNCTION I’M
GOING TO FOCUS ON IS ENERGY, AND THE REASON IS
THAT PROTEINS AREN’T USED FOR ENERGY
TO A GREAT EXTENT. AND THE REASON IS THAT WE HAVE
THIS WONDERFUL STORE OF FAT, OUR BODY, THAT IS A REALLY
GOOD SOURCE OF ENERGY, NINE CALORIES PER GRAM. CARBOHYDRATES AREA VERY
GOOD SOURCE OF ENERGY. PROTEINS ARE NEEDED FOR
ALL THESE FUNCTIONS. WHY WOULD WE WANT TO
TAKE A PROTEIN AND TAKE THOSE AMINO ACIDS,
DISASSEMBLE THEM AND USE THEM FOR ENERGY WHEN WE HAVE OTHER
REALLY GOOD SOURCES OF ENERGY? AND THAT’S WHAT YOUR
BODY IS THINKING. WE DON’T WANT TO USE
PROTEIN FOR ENERGY, BUT WE CAN USE PROTEIN
FOR ENERGY IF NECESSARY. SO I’M GOING TO
GO OVER THESE QUICKLY. REMEMBER THIS IS
OUR CARBOHYDRATE. WHEN CARBOHYDRATE IS USED FOR
ENERGY WE TAKE THESE CARBONS, REMEMBER THESE ARE
TWO CARBON FRAGMENTS, AND THIS WILL PRODUCE ENERGY. AND THIS WILL GIVE YOU
FOUR CALORIES PER GRAM. AND REMEMBER OUR FAT IS THE,
YOU KNOW, SHORT, FATTY ACID CHAIN OR
REPRESENTATION OF THAT. AGAIN, BROKEN DOWN TO THESE
TWO CARBON UNITS, SAME THING. THIS GIVES US NINE
CALORIES PER GRAM BECAUSE THIS IS ACTUALLY MUCH LONGER,
REMEMBER. BECAUSE MOST OF OUR FATS
ARE LONG CHAIN FATTY ACIDS. AND THEN LOOK AT PROTEIN. LOOK HOW DIFFERENT PROTEIN LOOKS
COMPARED TO THAT CARBOHYDRATE. WHEN WE USE PROTEIN FOR ENERGY,
AGAIN, IT’S GOING TO BE BROKEN DOWN
INTO THESE TWO CARBON FRAGMENTS. THOSE TWO CARBON FRAGMENTS ARE
GOING TO BE USED FOR ENERGY, BUT THERE’S ALSO
THIS NITROGEN HERE. WELL,
EVEN THOUGH YOU’RE GOING TO GET THE FOUR CALORIES PER GRAM, YOU CAN PUT A LOT OF ENERGY
INTO BREAKING THIS DOWN. SO IT’S NOT NEARLY AS EFFICIENT
AS BREAKING DOWN CARBOHYDRATES. IN ADDITION, THERE’S
NOW THIS NITROGEN. NITROGEN IS THIS KEY COMPONENT
TO THESE AMINO ACIDS, AND AMINO ACIDS ARE THE
BUILDING BLOCKS FOR PROTEINS. AND PROTEINS ARE ESSENTIAL. WE HAVE THESE
STRUCTURES IN OUR BODY, WHICH IS OUR SKIN,
AND OUR CARTILAGE, AND OUR MUSCLE, AND ANTIBODIES, AND BUFFERS, AND ACID,
AND BASE BALANCE, AND WE NEED ALL OF THOSE
PROTEINS FOR THOSE FUNCTIONS. SO WHEN WE USE
PROTEIN FOR ENERGY, WE’RE BASICALLY WASTING IT. SO THIS IS WHERE THE
TERM WASTING COMES FROM. AND THIS IS THE END OF OUR
SECTION ON PROTEIN FUNCTIONS.