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NUCLEIC ACID (an organic cmpd.)

NUCLEIC ACID (an organic cmpd.)

DEOXYRIBONUCLEIC ACID

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DNADNACONTROLS SYNTHESIS OF

PROTEINS (ENZYMES) AND ALL THOSE THAT CONTROL CELL FUNCTIONS

FORMS A LINK BETWEEN GENERATIONS (THROUGH MITOSIS AND MEIOSIS)

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TYPES OF NUCLEIC ACID’STYPES OF NUCLEIC ACID’S 1. DNA= DEOXYRIBONUCLEIC ACID

FUNCTION: 1. BLUE PRINT FOR LIFEFUNCTION: 2. REPLICATION (FOR CELL DIVISION)FUNCTION: 3. CONTROLS CHEMICAL MACHINERY OF CELL THROUGH RNA (DNA NEVER LEAVES THE NUCLEUS)

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DNA continues…DNA continues…

DISCOVERY OF DNA STRUCTURE

1953 DISCOVERED BY JAMES WATSON AND FRANCIS CRICK

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RNA = Ribonucleic AcidFUNCTION: 1. “MESSENGER MOLECULE” LEAVES THE NUCLEUS & GOES TO CYTOPLASM WHERE PROTEINS ARE SYNTHESIZED (TRANSCRIPTION)FUNCTION: 2. DIRECTS PROTEIN SYNTHESIS (TRANSLATION)

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STRUCTURE OF DNASTRUCTURE OF DNAMONOMERS (one part) OF DNA ARE

CALLED NUCLEOTIDESNUCLEOTIDES ARE MADE OF:

A PHOSPHATE GROUPPENTOSE (5 CARBON STRUCTURE) SUGAR CALLED DEOXYRIBOSE1 OF 4 NITROGENOUS BASES

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4 TYPES OF NUCLEOTIDES4 TYPES OF NUCLEOTIDESEACH ONE HAS THE

SAME PHOSPHATE GROUPSAME SUGAR = DEOXYRIBOSEDIFFERENT NITROGENOUS BASE

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NITROGENOUS BASESNITROGENOUS BASESTHERE ARE FOUR…

ADENINE=ATHYMINE=TGUANINE =GCYTOSINE=C

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TWO TYPES (Catagories) OF NITROGEN BASES

TWO TYPES (Catagories) OF NITROGEN BASES1.PURINE = DOUBLE RINGED

STRUCTURE ADENINE(A) AND GUANINE (G)

2.PYRIMIDINE = SINGLE RINGED STRUCTURE

THYMINE (T) AND CYTOSINE (C)

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LADDER MODEL PROPOSEDLADDER MODEL PROPOSEDPROPOSED IN 1953 BY J. WATSON AND

F. CRICKSIDES MADE OF PHOSPHATE AND

SUGAR“RUNGS” (CROSS LINKS) ARE

COMPLEMENTARY BASESA-T, C-G

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“LADDER” con’t“LADDER” con’tLADDER IS TWISTED IN THE FORM OF A “DOUBLE HELIX” (DOUBLE STRANDED)

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STRUCTURE OF RNASTRUCTURE OF RNASINGLE STRAND OF NUCLEOTIDESNUCLEOTIDES =

PHOSPHATE GROUPPENTOSE (5 CARBON) SUGAR CALLED RIBOSENITROGENOUS BASES

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4 NITROGENOUS BASES OF RNA4 NITROGENOUS BASES OF RNAADENINE = ACYTOSINE = CGUANINE = GURACIL = U NOTE *NO THYMINE IN RNA*

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RNA con’tRNA con’tLOCATION OF RNA

1. NUCLEUS2. CYTOPLASM

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REPLICATION OF DNAREPLICATION OF DNADNA MUST BE REPLICATED

(COPIED) IN ORDER TO BE PASSED ON TO ANOTHER GENERATION…THIS OCCURS IN THE “S” PHASE OF INTERPHASE

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WATSON AND CRICK SAID...WATSON AND CRICK SAID... A. DNA STRANDS SEPARATE B. EACH STRAND IS A TEMPLATE

(PATTERN) C. NUCLEOTIDES LINE UP - “BASE PAIRING”

CHARGAFF’S RULES= A-T, C-G D. ENZYMES LINK NUCLEOTIDES

TOGETHER

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CLOSE UP OF REPLICATIONCLOSE UP OF REPLICATION A COMPLEX…A LOT GOIN’ ON! B. RAPID…PROK. 1x EVERY 20MIN. C. ACCURATE…OR ELSE YOU GET

MUTATIONS (ONLY 1 PER BILLION NUCLEOTIDES IS WRONG)

D. REQ. ENZYMES…A LOT OF ENZYMES

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STRAND SEPARATIONSTRAND SEPARATIONA. HELICASE…OPENS UP THE

LADDER AT THE APPROPRIATE LOCATION

B. SINGLE STRAND BINDING PROTEINS…KEEP THE STRANDS OF DNA SEPARATED

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SYNTHESIS OF NEW DNASYNTHESIS OF NEW DNA

A. DNA POLYMERASE I…HELPS PLACE THE NUCLEOTIDES IN PROPER ALIGNMENT AND LINKS THEM TOGETHER.

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PROOFREADINGPROOFREADINGINITIALLY THERE ARE 1 IN 10,000

NUCLEOTIDE MISTAKES.ENZYMES “READ” DNA FOR

MISTAKES

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DNA REPAIRDNA REPAIRUSE OF AT LEAST 50 ENZYMES!A. DIRECT REPAIR

DNA POLYMERASE III - CHECKS THE DNA AND STOPS REPLICATION WHEN IT FINDS THE ERRORKNOWS WHICH IS NEW-VS-OLD BECAUSE THE OLD IS METHYLATED

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B. EXCISION REPAIR…CUTS OUT THE BAD NUCLEOTIDES THAT ARE IN THE WRONG PLACE.

A “BUMP” INDICATES WHERE THE MISTAKE IS LOCATEDENZYMES=LIGASE AND POLYMERASE I

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MATCH THE NUCLEOTIDESMATCH THE NUCLEOTIDESA-C-T-G-G-T-A-A-A-C-G-C-C-ACHARGAFF’S RULE= HE STATED

THAT A’S COMPLEMENTED T AND VICE VERSA, AND THAT C COMPLEMENTED G AND VICE VERSA.

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THE WORKINGS OF DNA AND RNATHE WORKINGS OF DNA AND RNAA. THE ORDER OF BASES IS

USED TO “SPELL OUT” THE BLUEPRINT OF PROTEINS/ENZYMES…

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B. DNA UNZIPS SO THAT HALF THE LADDER CAN BE COPIED BY mRNA.

C. DNA STAYS IN THE NUCLEUS.D. mRNA TAKES THE MESSAGE TO

THE RIBOSOME IN THE CYTOPLASM.

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THREE TYPES OF RNATHREE TYPES OF RNA A. mRNA =MESSENGER FROM NUCLEAR

DNA TO CYTOPLASM B. tRNA = TRANSFER’S THE AMINO ACIDS

TO THE RIBOSOME IN THE CORRECT ORDER ACCORDING TO THE mRNA

C. rRNA = RIBOSOMAL RNA, PART OF THE RIBOSOME STRUCTURE

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TRANSCRIPTIONTRANSCRIPTION LIKE A “SCRIBE”- MAKING A COPY OF

ITSELF EXACTLY A. mRNA IS TRANSCRIBED FROM THE DNA

TEMPLATE B. ONE SIDE OF DNA IS COPIED (INTO

mRNA)=SENSE STRAND C. OTHER SIDE OF DNA NOT COPIED=

ANTISENSE STRAND

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D. mRNA LEAVES THE NUCLEUS AS THE EXACT COPY OF DNA TO TELL THE RIBOSOME AND tRNA WHAT ORDER TO PUT THE AMINO ACIDS INTO.

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HOW TRANSCRIPTION OCCURS...HOW TRANSCRIPTION OCCURS...RNA POLYMERASE BONDS TO

THE “PROMOTER” (PROMOTES START OF TRANSCRIPTION)

RNA POLYMERASE MOVES ALONG THE GENE AND THE 2 DNA STRANDS SEPERATE

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SENSE STRAND COPIEDNUCLEOTIDES

COMPLEMENTARY PAIRED C-G, A- URACIL (U) IN RNA LINKED BY RNA POLYMERASE

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AS THE mRNA GETS LONGER IT PEELS AWAY FROM THE DNA AND DNA RE-BONDS VIA HYDROGEN BONDS

mRNA STRAND IS FORMED AT 60 NUCLEOTIDES PER SECOND

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TRANSCRIPTION CONTINUES UNTIL IT COMES IN CONTACT WITH THE “TERMINATOR” (STOP) SEQUENCE

mRNA MOLECULE DETACHES FROM THE GENE

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TRANSLATIONTRANSLATION“TRANSLATION” IS TAKING THE

LANGUAGE OF DNA (VIA mRNA) TRANSLATING IT INTO THE LANGUAGE OF PROTEINS.

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TRANSLATION...TRANSLATION...IS THE MAKING OF A PROTEIN

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STEPS IN TRANSLATIONSTEPS IN TRANSLATION1. mRNA ATTACHES TO THE

RIBOSOME2. AMINO ACIDS IN THE CYTOPLASM

ARE PICKED UP BY THE transferRNA (tRNA)

EACH tRNA CARRIES ONLY ONE TYPE OF AMINO ACID AS DETERMINED BY THE “ANTICODON”

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CON’TCON’T

THE tRNA PLACES AMINO ACIDS IN THE PROPER ORDER ACCORDING TO THE mRNA

THE AMINO ACIDS ARE ATTACHED TO ONE ANOTHER BY DEHYDRATION SYNTHESIS AND THE HELP OF ENZYMES (OF COURSE :) )

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CODES FOR A.A.’SCODES FOR A.A.’STHERE ARE 20 AMINO ACIDS THREE BASE CODE FOR ONE AMINO

ACID…AUG = METHIONINE, ALSO THE START CODONSee the TABLE WITH ALL THE CODONS AND MATCHING A.A.’S

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“CODON”“CODON”THE CODON IS ON THE mRNATHE CODON IS A THREE BASE

“WORD” THAT INDICATES WHAT AMINO ACID IS SUPPOSED TO BE PLACED AT THAT LOCATION

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“ANTICODON”“ANTICODON” THE ANTICODON IS ON THE tRNA THE tRNA PICKS UP A.A.’S IN THE

CYTOPLASM ACCORDING TO ITS ANTICODON

THE tRNA BRINGS THE AMINO ACID TO THE mRNA TO MATCH IT WITH ITS CODON

THIS BUILDS A PROTEIN

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“DEGENERATE”“DEGENERATE”THIS MEANS THAT THERE IS

GREATER THAN ONE CODON THAT WILL CODE FOR AN AMINO ACID

WHY? IT REDUCES THE CHANCE FOR A MUTATION

EX.= UCU,UCC,UCA,UCG ALL CODE FOR SERINE

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GENE MUTATIONSGENE MUTATIONSA CHANGE IN THE SEQUENCE

OF NUCLEOTIDES WITHIN A GENE

THE CAT ATE THE BAT

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BASE-PAIR SUBSTITUTIONBASE-PAIR SUBSTITUTION

WHEN A PAIR OF NUCLEOTIDES IS REPLACED BY A DIFFERENT BASE PAIR

“POINT MUTATION”

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Example...Example...

THE MUTATION CAN BE HARMFUL OR NOT

CTT -VS- CAT (DNA)GAA -VS- GUA (mRNA)GLUTAMIC ACID IS REPLACED WITH

VALINE AND SICKLE CELL ANEMIA OCCURS…HARMFUL

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C0N’TC0N’T

IF A POINT MUTATION OCCURS LIKE THIS…AAA -VS- AAG… IT STILL CODES FOR PHENYLALANINE

RECALL THAT THE CODE IS DEGENERATEA MUTATION OCCURRED BUT THE CODON WAS STILL FOR THE SAME AMINO ACID

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DELETION/ INSERTIONDELETION/ INSERTIONA LOSS OR ADDITION OF ONE OR MORE

BASESCAUSES A “FRAMESHIFT” MUTATIONEXAMPLE…THE CAT ATE THE BATMUTATION…THC ATA TET HEB AT

(DELETION)MUTATION… THE CAT ATE TTH EBA T

(INSERTION)

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MUTAGENSMUTAGENSFACTORS IN THE ENVIRONMENT

THAT CAUSE MUTATIONS TO OCCUR IN THE REPLICATION PHASE OF THE CELL CYCLE

EXAMPLES…SMOKING, CAFFEINE, U-V RAYS

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CANCERCANCERUNCONTROLLED CELL GROWTH DUE

TO A MUTATION IN THE GENETIC CODETUMORS GROW, AND GROW THEIR

OWN BLOOD SUPPLY AND CONTINUE TO THRIVE AND PARTS OF THOSE TUMORS (CELLS) BREAK OFF AND CAN THRIVE ELSE WHERE IN THE BODY