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DNA Deoxyribonucleic Acid “The Blueprint of Life” I. DNA Structure & Function
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A. What is DNA? 1. Organic molecule 2. Nucleic acid
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B.Where is it located ? 1. Nucleus 2. Chromosomes DNA
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Chromosomes in Nucleus
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C. Structure of DNA 1. Nucleotides a. Phosphoric Acid b. Deoxyribose sugar c. Nitrogenous bases: Adenine-Thymine Guanine-Cytosine 2. Ladder Shape 3. Double strand, helix twist
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Ladder Shape (Sides & Rungs) Sides: Phosphoric Acid Sugar Phosphoric Acid Rungs: A-T T-A G-C C-G Sugar Acid Sugar Acid Sugar T-A G-C C-G A-T
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Watson & Crick’s Double helix:
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D. What is DNA’s Function ? Hereditary Instructions Chemical code for every trait “Blueprint” for making Proteins
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Chromosome DNA Code: Genes = Segments of DNA Code for a trait Hair Color Eye Color
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DNA Chromosome Code: Triplets= Sets of 3 Nucleotides Code for Trait Acid Sugar-T-A-Sugar Acid Sugar-G-C-Sugar Acid Sugar-C-G-Sugar
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DNA Chromosome Code: Like Morse Code: Hair = *** *- ** *-* Or DNA A-T A-T G-C C-G T-A C-G
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DNA Replication Chromosomes double Mitosis Late Interphase 2n to 4n 2N
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E. Steps for DNA Replication: 1. DNA untwists 2. DNA unzips 1. Enzyme: Helicase 2. Replication Fork: 3. RNA Primer 1. Enzyme: Primase 4. Corresponding base pairs Line up In sets of 3 nucleotides Triplets or “codons” 5. DNA reforms 6. 2 strands twist into helix Identical Strand
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DNA Replication Cont: 4. base pairs / Complementary Strand Line up In sets of 3 nucleotides: Triplets Or “codons Enzyme: DNA Polymerase III 5. Fragments Connect: Enzyme: Ligase
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DNA Replication Cont: 6. RNA is replaces and proofread Enzyme: Polymerase I 7. DNA reforms and twists to form double helix
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RNA Ribonucleic Acid “DNA messenger & taxi” II. RNA Structure & Function
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A. What is RNA? 1. Organic Molecule 2. Nucleic Acid 3. mRNA= messenger tRNA= transfer
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B. Where is RNA located? 1. mRNA in nucleus & cytoplasm 2. tRNA only in cytoplasm mRNA tRNA
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B. What is RNA’s structure? Acid Sugar-Base Acid Sugar-Base Acid Sugar-Base Acid Sugar-Base 1. Nucleotides= a. Phosphoric Acid b. Ribose sugar c. Nitrogenous Bases: Adenine-Uracil Guanine-Cytocine 2. Single Strand 3. No Twisted helix
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Comparison of RNA & DNA: Acid Sugar-Base Acid Sugar-Base Acid Sugar-Base Acid Sugar-Base Acid Sugar-Base-Sugar Acid Sugar-Base-Sugar Acid Sugar-Base-Sugar Acid RNA DNA Ladder Deoxy- ribose Ribose Uracil Thymine
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D. What are RNA’s functions: 1. mRNA= Copies the DNA code Deliveries message to Ribosome Protein Factories
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Why not send the original DNA code out? DNA might be damaged! mRNA components are reused To copy more messages Original DNA mRNA copy
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RNA function cont. 2. tRNA: in cytoplasm Picks up an amino acid “Taxis” the aa to the Ribosome protein factories tRNA Amino acid
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III. Protein Synthesis Assembling Proteins from the DNA Instructions
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A. Transcription : 1. mRNA is copied off of DNA 2. In nucleus 3. Steps: DNA untwists DNA unzips RNA codons line up
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Transcription: mRNA has: Ribose sugar Uracil instead of thymine bases Nuclear membrane allows it to leave! DNA Code mRNA ATCGATCG UAGCUAGC
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Transcription in The nucleus mRNA copy DNA
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B. Translation = Conversion of the message (mRNA Code) Into a protein By the ribosome factories
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B.Translation 1. mRNA arrives at the Ribosome 2. tRNA picks up an amino acid 3. tRNA delivers the aa to the ribosome 4. aa are assembled into polypeptide proteins U A G C G C U A mRNA code tRNA taxi
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tRNA delivers amino acid 2. Peptide bond forms 3. tRNA leaves ribosome 4. Polypeptide Chain of amino acids grows
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Summary: DNA Replication: Make duplicate DNA In nucleus Copy the chromosomes For Mitosis Protein Synthesis: 1. Transcrition: Make mRNA From DNA 2. Translation: Make protein Off mRNA code Using amino acids
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