DNA Deoxyribonucleic Acid “The Blueprint of Life” I. DNA Structure & Function

A. What is DNA? 1. Organic molecule 2. Nucleic acid

B.Where is it located? 1. Nucleus 2. Chromosomes X DNA

Chromosomes in Nucleus

C. Structure of DNA Nucleotides a. Phosphoric Acid b. Deoxyribose sugar c. Nitrogenous bases: Adenine-Thymine Guanine-Cytosine 2. Ladder Shape 3. Double strand, helix twist

Ladder Shape (Sides & Rungs) Sugar Acid Sides: Phosphoric Acid Sugar Rungs: A-T T-A G-C C-G T-A G-C C-G A-T

Watson & Crick’s Double helix:

D. What is DNA’s Function? Hereditary Instructions Chemical code for every trait “Blueprint” for making Proteins

Genes = Segments of DNA Code for a trait Chromosome DNA Code: Eye Hair Color Genes = Segments of DNA Code for a trait X Eye Color

DNA Chromosome Code: Sets of 3 Nucleotides Code for Trait Triplets= X Acid Acid Sugar-T-A-Sugar Acid Acid Sugar-G-C-Sugar Sugar-C-G-Sugar X

*** *- ** *-* DNA Chromosome Code: A-T G-C C-G T-A *** *- ** *-* Like Morse Code: Hair = Or DNA A-T G-C C-G T-A

DNA Replication Chromosomes double Mitosis Late Interphase 2n to 4n 2N

E. Steps for DNA Replication: DNA untwists DNA unzips Corresponding base pairs Line up In sets of 3 nucleotides (triplets) Or “codons” DNA reforms 2 strands twist into helix Identical Strand

RNA Ribonucleic Acid “DNA messenger & taxi” II. RNA Structure & Function

A. What is RNA? Organic Molecule Nucleic Acid mRNA= Ribonucleic Acid messenger tRNA= transfer Ribonucleic Acid

mRNA in nucleus & cytoplasm B. Where is RNA located? mRNA in nucleus & cytoplasm tRNA only in cytoplasm mRNA mRNA tRNA

B. What is RNA’s structure? Nucleotides= a. Phosphoric Acid b. Ribose sugar c. Nitrogenous Bases: Adenine-Uracil Guanine-Cytocine 2. Single Strand 3. No Twisted helix Acid Sugar-Base

Comparison of RNA & DNA: Acid Sugar-Base Acid Acid Sugar-Base-Sugar Acid Acid Uracil Thymine Deoxy-ribose Ribose RNA DNA Ladder

D. What are RNA’s functions: mRNA= Copies the DNA code Deliveries message to Ribosome Protein Factories

Why not send the original DNA code out? DNA might be damaged! mRNA components are reused To copy more messages mRNA copy

RNA function cont. tRNA in cytoplasm Picks up an amino acid “Taxis” the aa to the Ribosome protein factories Amino acid tRNA

Assembling Proteins from the DNA Instructions III. Protein Synthesis Assembling Proteins from the DNA Instructions

A. Transcription: mRNA is copied off of DNA In nucleus Steps: DNA untwists DNA unzips RNA codons line up

Transcription: mRNA DNA Code A T C G U A G C I I I mRNA has: Ribose sugar Uracil instead of thymine bases Nuclear membrane allows it to leave! mRNA A T C G U A G C I I I DNA Code

Transcription in The nucleus DNA mRNA copy

B. Translation = Conversion of the message (mRNA Code) Into a protein By the ribosome factories

B.Translation A U A G C U mRNA code C mRNA arrives at the Ribosome tRNA taxi A mRNA arrives at the Ribosome tRNA picks up an amino acid tRNA delivers the aa to the ribosome aa are assembled into polypeptide proteins U C G U A G C mRNA code

2. Peptide bond forms tRNA delivers 3. tRNA leaves ribosome amino acid 4. Polypeptide Chain of amino acids grows 2. Peptide bond forms 3. tRNA leaves ribosome tRNA delivers amino acid

Summary: Protein Synthesis: Transcrition: Make mRNA From DNA Translation: Make protein Off mRNA code Using amino acids DNA Replication: Make duplicate DNA In nucleus Copy the chromosomes For Mitosis