NUCLEIC ACID (an organic cmpd.)

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NUCLEIC ACID (an organic cmpd.)

• DEOXYRIBONUCLEIC ACID

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DNA

• CONTROLS 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 ACIDS

• 1. DNA DEOXYRIBONUCLEIC ACID
• FUNCTION 1. BLUE PRINT FOR LIFE
• FUNCTION 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

• DISCOVERY OF DNA STRUCTURE
• 1953 DISCOVERED BY JAMES WATSON AND FRANCIS CRICK

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• RNA Ribonucleic Acid
• FUNCTION 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 DNA

• MONOMERS (one part) OF DNA ARE CALLED NUCLEOTIDES
• NUCLEOTIDES ARE MADE OF
• A PHOSPHATE GROUP
• PENTOSE (5 CARBON STRUCTURE) SUGAR CALLED
  DEOXYRIBOSE
• 1 OF 4 NITROGENOUS BASES

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4 TYPES OF NUCLEOTIDES

• EACH ONE HAS THE
• SAME PHOSPHATE GROUP
• SAME SUGAR DEOXYRIBOSE
• DIFFERENT NITROGENOUS BASE

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NITROGENOUS BASES

• THERE ARE FOUR
• ADENINEA
• THYMINET
• GUANINE G
• CYTOSINEC

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TWO TYPES (Catagories) OF NITROGEN BASES

• 1.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 PROPOSED

• PROPOSED IN 1953 BY J. WATSON AND F. CRICK
• SIDES MADE OF PHOSPHATE AND SUGAR
• RUNGS (CROSS LINKS) ARE COMPLEMENTARY BASES
• A-T, C-G

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LADDER cont

• LADDER IS TWISTED IN THE FORM OF A DOUBLE HELIX
  (DOUBLE STRANDED)

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STRUCTURE OF RNA

• SINGLE STRAND OF NUCLEOTIDES
• NUCLEOTIDES
• PHOSPHATE GROUP
• PENTOSE (5 CARBON) SUGAR CALLED RIBOSE
• NITROGENOUS BASES

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4 NITROGENOUS BASES OF RNA

• ADENINE A
• CYTOSINE C
• GUANINE G
• URACIL U
• NOTE NO THYMINE IN RNA

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RNA cont

• LOCATION OF RNA
• 1. NUCLEUS
• 2. CYTOPLASM

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REPLICATION OF DNA

• DNA MUST BE REPLICATED (COPIED) IN ORDER TO BE
  PASSED ON TO ANOTHER GENERATIONTHIS OCCURS IN
  THE S PHASE OF INTERPHASE

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WATSON AND CRICK SAID...

• A. DNA STRANDS SEPARATE
• B. EACH STRAND IS A TEMPLATE (PATTERN)
• C. NUCLEOTIDES LINE UP - BASE PAIRING
• CHARGAFFS RULES A-T, C-G
• D. ENZYMES LINK NUCLEOTIDES TOGETHER

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CLOSE UP OF REPLICATION

• A COMPLEXA LOT GOIN ON!
• B. RAPIDPROK. 1x EVERY 20MIN.
• C. ACCURATEOR ELSE YOU GET MUTATIONS (ONLY 1
  PER BILLION NUCLEOTIDES IS WRONG)
• D. REQ. ENZYMESA LOT OF ENZYMES

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STRAND SEPARATION

• A. HELICASEOPENS UP THE LADDER AT THE
  APPROPRIATE LOCATION
• B. SINGLE STRAND BINDING PROTEINSKEEP THE
  STRANDS OF DNA SEPARATED

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SYNTHESIS OF NEW DNA

• A. DNA POLYMERASE IHELPS PLACE THE NUCLEOTIDES
  IN PROPER ALIGNMENT AND LINKS THEM TOGETHER.

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PROOFREADING

• INITIALLY THERE ARE 1 IN 10,000 NUCLEOTIDE
  MISTAKES.
• ENZYMES READ DNA FOR MISTAKES

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DNA REPAIR

• USE OF AT LEAST 50 ENZYMES!
• A. DIRECT REPAIR
• DNA POLYMERASE III - CHECKS THE DNA AND STOPS
  REPLICATION WHEN IT FINDS THE ERROR
• KNOWS WHICH IS NEW-VS-OLD BECAUSE THE OLD IS
  METHYLATED

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• B. EXCISION REPAIRCUTS OUT THE BAD NUCLEOTIDES
  THAT ARE IN THE WRONG PLACE.
• A BUMP INDICATES WHERE THE MISTAKE IS LOCATED
• ENZYMESLIGASE AND POLYMERASE I

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MATCH THE NUCLEOTIDES

• A-C-T-G-G-T-A-A-A-C-G-C-C-A
• CHARGAFFS RULE HE STATED THAT AS COMPLEMENTED
  T AND VICE VERSA, AND THAT C COMPLEMENTED G AND
  VICE VERSA.

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THE WORKINGS OF DNA AND RNA

• A. 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 RNA

• A. mRNA MESSENGER FROM NUCLEAR DNA TO CYTOPLASM
• B. tRNA TRANSFERS 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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TRANSCRIPTION

• 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...

• 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 COPIED
• NUCLEOTIDES 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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TRANSLATION

• TRANSLATION IS TAKING THE LANGUAGE OF DNA (VIA
  mRNA) TRANSLATING IT INTO THE LANGUAGE OF
  PROTEINS.

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TRANSLATION...

• IS THE MAKING OF A PROTEIN

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STEPS IN TRANSLATION

• 1. mRNA ATTACHES TO THE RIBOSOME
• 2. 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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CONT

• 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.S

• THERE ARE 20 AMINO ACIDS
• THREE BASE CODE FOR ONE AMINO ACID
• AUG METHIONINE, ALSO THE START CODON
• See the TABLE WITH ALL THE CODONS AND MATCHING
  A.A.S

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CODON

• THE CODON IS ON THE mRNA
• THE CODON IS A THREE BASE WORD THAT INDICATES
  WHAT AMINO ACID IS SUPPOSED TO BE PLACED AT THAT
  LOCATION

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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

• 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 MUTATIONS

• A CHANGE IN THE SEQUENCE OF NUCLEOTIDES WITHIN A
  GENE
• THE CAT ATE THE BAT

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BASE-PAIR SUBSTITUTION

• WHEN A PAIR OF NUCLEOTIDES IS REPLACED BY A
  DIFFERENT BASE PAIR
• POINT MUTATION

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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 OCCURSHARMFUL

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C0NT

• IF A POINT MUTATION OCCURS LIKE THISAAA -VS-
  AAG IT STILL CODES FOR PHENYLALANINE
• RECALL THAT THE CODE IS DEGENERATE
• A MUTATION OCCURRED BUT THE CODON WAS STILL FOR
  THE SAME AMINO ACID

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DELETION/ INSERTION

• A LOSS OR ADDITION OF ONE OR MORE BASES
• CAUSES A FRAMESHIFT MUTATION
• EXAMPLETHE CAT ATE THE BAT
• MUTATIONTHC ATA TET HEB AT (DELETION)
• MUTATION THE CAT ATE TTH EBA T (INSERTION)

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MUTAGENS

• FACTORS IN THE ENVIRONMENT THAT CAUSE MUTATIONS
  TO OCCUR IN THE REPLICATION PHASE OF THE CELL
  CYCLE
• EXAMPLESSMOKING, CAFFEINE, U-V RAYS

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CANCER

• UNCONTROLLED CELL GROWTH DUE TO A MUTATION IN THE
  GENETIC CODE
• TUMORS 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