DNA and RNA

Slide 1: DNA and RNA DNA

Slide 2: What does DNA do? • Determines characteristics of an organism. • Transmits these characteristics from cell-to-cell and from parent-to-offspring.

Slide 3: DNA stands for… • Deoxyribonucleic acid. • Found in cell nucleus in eukaryotes

Slide 4: Structure of DNA 1. Deoxyribose (sugar) 3. Phosphate group (PO4) 5. Nitrogenous base

Slide 5: Structure of DNA • Backbone: alternating sugars and phosphate groups • “Rungs”: one of four nitrogenous bases (may be up to 100 million in one molecule)

Slide 6: Watson and Crick • James Watson and Francis Crick discovered that DNA takes the shape of a double helix, with two strands curled around each other.

Slide 7: Nitrogenous Bases • Order of nitrogenous bases control traits • A “gene” is a certain number of bases • Specific sequences tell the cell which proteins to make

Slide 8: Nitrogenous Bases: 4 types • Purines – Adenine – Guanine • Pyrimidines – Thymine – Cytosine

Slide 9: Base Pairs • In a DNA sequence, an “A” on one strand pairs only with a “T” on the other and a “C” pairs only with a “G” A-T-G-G-T-A-C-G-T-T pairs with T-A-C-C-A-T-G-C-A-A

Slide 10: Replication • DNA copies itself through a process called replication • Molecule “unzips” and matching strands are created by an enzyme called DNA Polymerase • Enzymes are proteins that cause or speed up a chemical change

Slide 11: Make the matching strand? CTTTGGCATCCGTAACGA

Slide 12: Analogy • Think of the bases as an alphabet. • STOP and POTS are spelled using the same letters, but mean completely different things. • CATACG and TCAGAC are likewise

Slide 13: Summarize Four Things 1. What DNA stands for 3. Where DNA is located 5. Function of DNA 7. Structure of DNA

Slide 14: Group Discussion • You know that DNA is a long chain of various small molecules, called nitrogenous bases. How could this affect the color of your skin, what diseases you are predisposed to, or how high/low your voice is? • CREATE A HYPOTHESIS!

Slide 15: DNA’s Function • DNA CODES FOR PROTEINS, THE STRUCTURAL BUILDING BLOCKS OF ORGANISMS!!! • See a problem with this?

Slide 16: DNA and RNA RNA

Slide 17: RNA • Cells have to make RNA from DNA • RNA has a different “language”, but otherwise is very similar • Any musicians know what this is called?

Slide 18: “Language” of RNA • Base pairs are the same, but Thymine (T) is replaced by Uracil (U) • Enzyme called RNA polymerase creates strands of RNA that match strands of DNA

Slide 19: RNA/DNA differences DNA RNA Deoxyribose sugar Ribose sugar Double-stranded Single-stranded Thymine (T) base Uracil (U) base

Slide 20: Importance of RNA • Allows genetic material to travel from the nucleus to the ribosome, where proteins are made • 3 types of RNA

Slide 21: Transcription • RNA bases must compliment DNA bases • RNA polymerase does not transcribe the entire DNA molecule • Bonds at a site called the “promoter” • mRNA (messenger RNA) is created and leaves nucleus

Slide 22: Transcription DNA Strand: C G T A A T A C A T G mRNA Strand:

Slide 23: DNA and RNA Protein Synthesis

Slide 24: Review • What DNA strand would match up with: A–G–G–T–A–C–C–A–T • What is RNA? How is it different from DNA? • What molecules are made in the ribosomes using the “code” from RNA?

Slide 25: Ribosomes • Ribosomes are made of protein and ribosomal RNA (rRNA) • Function: creating specific proteins from chains of RNA

Slide 26: Codons • Codon: a three-base sequence of mRNA that specifies a certain amino acid

Slide 29: Special Codons • Start codon (AUG) • Stop codons (UAA, UAG, UGA)

Slide 30: • The process of going from the “language” of nucleic acids to the “language” of amino acids is called…

Slide 31: Translation • Assembling proteins from mRNA • Transfer RNA (tRNA) molecules are the gateway between mRNA and proteins

Slide 32: tRNA • Structure: – RNA loop with an amino acid on one end • A certain codon (ex.: GUA) matches with a tRNA molecule with a certain amino acid (ex.: valine)

Slide 33: tRNA and Amino Acids • UCUCAGAAU • What tRNA matches up with the mRNA codon “UCU”? • CAG? AAU?

Slide 34: DNA A T G T G T C C A T C G • What is the matching DNA strand? • What RNA strand would be created? • What protein would be created?