- WELCOME TO NUCLEIC ACIDS PART 1.
WE'LL HAVE A BRIEF INTRODUCTION AND WE'LL LOOK AT NUCLEOTIDES,
THE BASIC BUILDING CLOCK--
BLOCK OF NUCLEIC ACIDS.
LET'S GO AHEAD AND GET STARTED.
ALL RIGHT.
AS YOU MAY OR MAY NOT ALREADY KNOW, DNA IS DEOXY--
I DON'T KNOW WHERE-- RIBOSE,
THERE WE GO, NUCLEIC ACID.
ALL RIGHT. SO DNA.
AND THEN OF COURSE RNA IS RIBONUCLEIC ACID.
OKAY. ALL RIGHTY.
SO, THEY WORK TOGETHER, THEY HAVE SIMILAR FUNCTIONS.
LET'S MAKE SURE THAT WE UNDERSTAND THE FUNCTIONS, RIGHT?
SO BASICALLY, DNA IS THE LIBRARY,
IT STORES INSTRUCTIONS FOR MAKING PROTEINS, ALL RIGHT?
AND WHEN WE HEAR THE WORD PROTEIN,
WELL PROTEINS HAVE MANY FUNCTIONS.
WE'RE GOING TO REALLY THINK ABOUT THEIR ROLE,
RIGHT AS ENZYMES. YOU KNOW.
SO, PROTEIN THING--
PROTEINS HAVE MORE ROLES THAN THAT BUT I THINK
THAT'S A KEY PLACE TO BE LOOKING BECAUSE THE ENZYMES
THAT ARE ACTIVATED WITHIN A CELL GIVE
IT'S PERSONALLY AND CHARACTER.
NOW, THE RNA IT WORKS IN CONJUNCTION
WITH THE RIBOSOMES TO DIRECT THE ASSEMBLY OF THE AMINO ACIDS.
OKAY-- CAN'T KEEP UP WITH MY WRITING,
CATCH UP WITH MY WORDS, RIGHT?
SO THE RNA WITH THE RIBOSOMES WILL--
WORKS TO DIRECT THE ASSEMBLY OF AMINO ACIDS. OKAY.
AND REMEMBER WE'LL JUST START USING AA FOR AMINO ACIDS,
RIGHT-- TO CREATE THE PRIMARY STRUCTURE OF PROTEINS. OKAY.
SO THE DNA HOLDS THE RECIPE BUT THE RNA IS THE ONE
THAT ACTUALLY WORKS WITH THE RIBOSOMES
TO BUILD THE PROTEINS.
SO, THE RIBOSOMES, RIGHT?
THOSE ARE THE CELLULAR STRUCTURES LOCATED
IN THE CYTOSOL WHERE POLYPEPTIDES ARE SYNTHESIZED SO
NOTHING TOO NEW THERE.
SO IT JUST HELPS US KNOW WHERE THEY ARE, RIGHT?
LOCATED IN THE CYTOSOL RIGHT WHERE--
AND WE CALL THEM REMEMBER THE LANGUAGE OF PROTEINS,
RIGHT, WE CALL THEM POLYPEPTIDES AT THIS POINT.
WE DON'T CALL THEM PROTEINS YET
BECAUSE THEY NEED TO HAVE TO THEIR SECONDARY,
TERTIARY, AND POSSIBLY QUATERNARY STRUCTURE CREATED
BEFORE THEY ASSUME A BIOLOGICAL FUNCTION.
SO IT'S INTERESTING THOUGH BECAUSE I ALWAYS THOUGHT
LIKE EVERY CELL HAD DNA BUT IT TURNS OUT,
RIGHT, WHEN A RED BLOOD CELL IS PRODUCED
AS SOON AS IT MATURES IT KICKS OUT
ITS DNA TO MAKE ROOM FOR MORE HEMOGLOBIN.
SO IT ACTUALLY HAS NO NUCLEUS,
NO DNA AND IS NOT ABLE TO DIVIDE.
IT'S INTERESTING THEY PRODUCE--
THEY ALSO DON'T HAVE MITOCHONDRIA.
SO, ALL OF THEIR ENERGY IS PRODUCED FROM GLYCOLYSIS,
AND WHEN YOU HEAR THE WORD GLYCOLYSIS,
RIGHT, YOU THINK ABOUT GLUCOSE GOING TO PYRUVATES. OKAY.
OH, AND THAT'S RIGHT HERE, RIGHT?
GLUCOSE GOING TO PYRUVATE MOLECULES.
ALL RIGHT.
AND THEN, MITOCHONDRIA,
IT'S HARD TO IMAGINE CELLS WITHOUT MITOCHONDRIA, RIGHT?
BECAUSE ALL KINDS OF IMPORTANT STUFF HAPPENS THERE.
WE GOT THIS CITRIC--
CITRIC ACID CYCLE, THE ELECTRON TRANSPORT CHAIN,
AND OXIDATIVE PHOSPHORYLATION.
SO, THERE WE GO. OKAY.
SO NOW, LET'S LOOK MORE CLOSELY--
SO THERE'S OUR INTRODUCTION.
SO NOW LET'S LOOK MORE CLOSELY AT THE BASIC BUILDING BLOCKS.
SO THOSE ARE DESCRIBED AS A NUCLEOTIDES.
SO, THE NUCLEOTIDES FOR DNA AND RNA HAVE MANY SIMILARITIES.
SO LET'S LEARN ABOUT THEM, RIGHT?
SO BUILDING BLOCKS
OF DNA AND RNA.
OKAY. ALL RIGHTY.
WELL, WE'LL JUST-- WE'LL START WITH A VERY SIMPLE STRUCTURE,
GENERIC STRUCTURE.
SO RIBOSE IS A FIVE CARBON SUGAR.
SO WE CAN USE A PENTAGRAM TO REPRESENT THE RIBOSE
OR THE DEOXYRIBOSE.
AND THEN THERE WILL BE A NITROGENOUS BASE.
AND WE--
YOU KNOW, WE'VE LEARNED ABOUT AMINES
AND SO WE RECOGNIZED IT, RIGHT? AND IT WILL BE--
SO IT'S A NITROGEN CONTAINING RINGS.
AND SO THESE BASES ARE VERY FANCY,
THEY'RE A RING STRUCTURE.
THE SUGAR IS--
THE SUGARS WILL DIFFER IN THIS POSITION RIGHT HERE.
THEY'LL EITHER BE RIBOSE OR DEOXYRIBOSE
AND YOU CAN IMAGINE WHAT, RIGHT?
SO THE DEOXY WE HAVE A LOSS OF OH, OKAY.
AND THEN THE LAST COMPONENT IS THE PHOSPHATE GROUP,
PI OR P1 AND THERE'S OUR PHOSPHATE
WHICH WE'VE COME TO RECOGNIZE. OKAY.
SO EACH NUCLEOTIDE HAS THESE THREE COMPONENTS.
THE NITROGENOUS BASE
AND THE SUGAR ARE OFTEN TALKED ABOUT BY THEMSELVES,
AND IN THIS CASE, WE CALLED THEM A NUCLEOSIDE.
HOWEVER, WHEN WE TAKE THE NUCLEOSIDE
AND ALSO ADD THE PHOSPHATE GROUP
THEN FOR ME THAT HELPS THE TIDE--
NUCLEOTIDE,
RIGHT, I THINK ABOUT THE TOTAL, RIGHT, ALL THREE COMPONENTS.
ALL RIGHTY.
SO THERE IS THE BASIC STRUCTURE OF NUCLEOTIDES.
AND NOW WE'LL LOOK A LITTLE MORE CLOSELY
AT EACH COMPONENT BY ITSELF.
WE'LL START WITH THE SUGAR SINCE IT'S IN THE CENTER
AND WE CAN SEE RIBOSE AND DEOXYRIBOSE.,SO
THE FIRST THING WE WANT TO LOOK FOR IS THAT,
THAT POSITION HERE THAT WE SEE RIGHT, THE LOSS, RIGHT,
LOSS OF OH.
AND NOW THIS--
WE'VE PRACTICED OUR SUGAR SO HERE'S THE HAWORTH,
SO WE SHOULD BE ABLE TO GO BACK AND FORTH.
SO IF WE FIND THIS HYDROXYL GROUP ON THE FISCHER, RIGHT?
PAY ATTENTION.
THERE'S OUR ANOMERIC CARBON WHICH WOULD BE RIGHT THERE.
SO, WE WOULD RECOGNIZE THIS IS THE CARBON TWO POSITION,
AND WE SEE WITH DEOXYRIBOSE WE HAVE THE LOSS OF THE OH.
ALL RIGHTY.
NOW, THE NUMBERING OF THE SUGARS--
BECAUSE WE HAVE THREE COMPONENTS,
THE SUGAR NUMBERS ARE ASSIGNED A PRIME.
SO OF COURSE THE ANOMERIC CARBON GETS THE LOWEST POSSIBLE NUMBER
AND THEN THE OTHER CARBONS JUST GET NUMBERED FROM THERE.
ALL RIGHTY.
SO, IT'S GREAT TO START WITH THE SUGAR
BECAUSE IT'S AT THE CENTER.
AND SO WE NOTICED THAT THE NITROGENOUS BASE, RIGHT, BONDS,
RIGHT, AT--
OFF OF CARBON ONE, SO ATTACHES OR BONDS
AND WE'LL CALL THOSE ONE PRIME.
AND THEN OF COURSE THE PHOSPHATE GROUP, RIGHT,
BONDS AT CARBON FIVE PRIME.
ALL RIGHTY. OKAY.
SO NOW, LET'S BUILD OUT AND LOOK MORE CLOSELY
AT THE NITROGENOUS BASE AND THE PHOSPHATE GROUP.
SO, ON THE NEXT PAGE WE'LL LOOK AT THE NITROGEN BASE
OR THE NITROGENOUS BASE
AND WE SEE THAT THERE ARE TWO BASIC FORMS.
SO THE NITROGENOUS BASES ARE EITHER DERIVATIVES
OF PURINE OR PYRIMIDINE.
ALL RIGHT.
SO NOTICE THE RING STRUCTURE WITH THE HEADER OF NITROGENS.
AND TO ME FOR SOME REASON
THE PURINE LOOKS A BIT LIKE A CAT,
RIGHT, LIKE THAT WOULD BE THE NOSE OF THE CAT
JUST NEEDS A LITTLE TAIL
AND CATS PURR SO THAT HELPED ME SORT OUT
THAT THE PURINE WAS THE TWO RING--
DIFFUSED RING STRUCTURE.
IF THAT HELPS YOU GREAT,
IF NOT HOPEFULLY YOU'LL HAVE A MORE CLEVER WAY TO THINK OF IT,
YOU CAN SHARE IT WITH ME.
ALL RIGHTY.
SO, WELL, FIRST WE'LL LOOK AT THE DNA BASES.
SO, WE'LL GO AHEAD AND FILL THIS IN.
SO THERE'S A BUNCH OF DOUBLE BONDS MISSING.
AND THEN OF COURSE HYDROGEN ALWAYS--
EXCUSE ME, NITROGEN ALWAYS WANTS THREE BONDS SO
ANY PLACE THAT THERE ARE THREE BONDS MISSING,
WE'RE GOING TO ADD A HYDROGEN.
SO, THIS FIRST PURINE DERIVATIVE IS ADENINE
AND IT GETS SYMBOLIZED WITH AN A.
AND THEN THE SECOND PURINE HAS THE AMIDE.
AND THEN WE SEE SOME MORE AMINES COMING OFF,
QUITE A FEW MORE DOUBLE BONDS AND THEN THERE'S A HYDROGEN,
SO THIS IS GUANINE AND WE SYMBOLIZE THAT WITH A G.
AND NOW WE LOOK THE PYRIMIDINE DERIVATIVES.
THE FIRST ONE, CYTOSINE ALSO HAS AN AMIDE FEATURE,
AND THERE'S A HYDROGEN THERE,
SO HERE IS CYTOSINE,
AND WE'LL SYMBOLIZE THAT WITH A C.
AND THEN WE HAVE THYMINE SO,
ALSO HAS THAT AMIDE FEATURE,
A COUPLE OF THEM AND THEN IT HAS A METHYL GROUP COMING OFF.
AND SO THIS IS THYMINE
AND THAT'S SYMBOLIZED WITH A T. OKAY.
NOW, FOR THE NITROGENOUS BASES
THEY ARE ALL THE SAME, ALL RIGHT.
SO WE WON'T GO THROUGH IT.
SO ADENINE IS THE SAME, GUANINE IS THE SAME,
YOU CAN PRACTICE FILLING THOSE IN YOURSELF.
AND THE CYTOSINE IS THE SAME BUT THERE IS NO THYMINE,
IT'S URACIL. OKAY.
SO LET'S FOCUS ON THE DIFFERENCES
BETWEEN THYMINE AND URACIL.
SO, IT'S ALMOST IDENTICAL EXCEPT IT'S--
THERE'S--
IT'S A HYDROGEN, RIGHT?
SO UP HERE, THIS IS A METHYL GROUP AND HERE IT'S A HYDROGEN.
SO THERE IS A ONE METHYL GROUP DIFFERENCE BETWEEN THE TWO.
OKAY. SO OTHERWISE,
EVERYTHING IS THE SAME. OKAY.
SO NOW LET'S GO TO THE PHOSPHATE GROUP,
AND THAT WELL FINISH UP OUR--
THE BASIC COMPONENTS OF OUR NUCLEOTIDES
WHICH THEN WILL LINK TOGETHER TO FORM THE NUCLEIC ACIDS.
ALL RIGHTY.
SO HERE WE SEE OUR SUGAR, RIGHT?
ONE PRIME, TWO PRIME, THREE PRIME,
FOUR PRIME, FIVE PRIME.
SO WE SEE THE NITROGENOUS BASE,
HERE A PYRIMIDINE COMING IN AT THE ONE PRIME CARBON,
AND THEN WE HAVE OUR PHOSPHATE.
SO LET'S GO AHEAD.
PUT AN ARROW TO THE BOND THAT LINKS THE RIBOSE
TO THE PHOSPHATE GROUP, RIGHT?
SO WE KNOW THE LINKAGE IS HERE AT THE OXYGEN, RIGHT?
SO REMEMBER, THAT REALLY
WE COULD JUST THINK OF THIS AS A VERY FANCY ALCOHOL
AND THAT THE PHOSPHATE ESTER BOND IS RIGHT THERE,
RIGHT, JUST LIKE WE WOULD WITH THE CARBONYL, RIGHT?
THINK ABOUT THE PHOSPHOROUS JUST
LIKE YOU WOULD AT CARBONYL ATOM SO THAT IS THE LINKAGE.
AND WHAT TYPE IS IT?
RIGHT, IT'S A PHOSPHO ESTER BOND.
ALL RIGHTY. OKAY.
SO THERE ARE TONS OF NUCLEOTIDES OUT THERE.
SO IN THIS CHAPTER WE'RE GOING TO FOCUS ON DNA AND RNA
BUT IT'S IMPORTANT IF YOU LOOK BACK AT SOME OF THE COMPOUNDS
THAT WE'VE STUDIED, RIGHT?
AMP, AB--
OOPS, ADP, ATP, THOSE ARE ALL--
THEY'RE ALSO NUCLEOTIDES AS WELL AS FAD AND NAD+.
SO THIS IS OUR--
A COMMON STRUCTURE THAT WE SEE THROUGH A VARIETY
OF BIOLOGICAL MOLECULES.
SO LET'S PRACTICE CONSTRUCTING A NUCLEOTIDE.
ALL RIGHTY.
SO WE'RE GOING TO HAVE PHOSPHATE,
ADENINE, AND DEOXYRIBOSE.
NOW, IN MY CLASS I WOULD NEVER EXPECT YOU TO MEMORIZE THESE,
I WOULD GIVE YOU THE COMPONENTS
BUT YOU SHOULD BE ABLE TO PUT THEM TOGETHER.
ALL RIGHTY.
SO, THE SUGAR, RIGHT,
GOES IN THE CENTER THERE'S OUR BODY RIBOSE,
AND THEN THIS IS DEOXYRIBOSE SO
WE KNOW THAT WE HAVE HYDROGEN'S HERE AND THEN WE--
YOU CAN REMEMBER THE RIBOSE STRUCTURE THERE,
RIGHT, SO THESE ARE ALL COMES FROM RIBOSE.
AND NOW WE WILL DO THE LINKAGE TO--
RIGHT, FROM ONE PRIME WE GO TO THE NITROGENOUS BASE,
AND NOTICE THAT IT'S GOT TO BE
ONE OF THE NITROGENS-- IF WE LOOK BACK,
RIGHT, THIS NITROGEN HAD A HYDROGEN BEFORE, RIGHT.
SO WE SUBSTITUTE THE R GROUP FOR WHERE THE HYDROGEN WAS.
AND THEN WE CAN JUST FILL IN THE REST RIGHT HERE.
THERE'S AN AMINE COMING OFF,
THERE WE ARE. OKAY.
SO WE'VE LINKED THE NITROGENOUS BASE
THROUGH THE ONE PRIME CARBON.
HERE'S OUR TWO PRIME, THREE PRIME, FOUR PRIME,
AND FIVE PRIME AND THEN
THE PHOSPHATE GROUP LINKS HERE, RIGHT?
SO THERE'S THE PHOSPHO ESTER BOND
AND THEN OF COURSE THIS IS THAT PHYSIOLOGICAL PH
SO WE SHOW THIS IONIZED. OKAY.
SO THAT'S AS ABOUT AS HARD
AS IT'S GETS WOULD BE TO ASSEMBLE A NUCLEOTIDE
FROM ITS THREE COMPONENTS,
THE FIVE CARBON SUGAR, THE NITROGENOUS BASE,
AND THE PHOSPHATE GROUP.
ALL RIGHTY.
SO, NOW WOULD BE A GREAT TIME TO WORK ON A FEW HOMEWORK PROBLEMS
TO REINFORCE YOUR UNDERSTANDING
OF THE BASIC STRUCTURE OF NUCLEOTIDES.