1 / 35

DNA, RNA And Protein Synthesis

DNA, RNA And Protein Synthesis. Modern Biology Pages 193 - 195. Function of DNA. Structure of DNA must allow the storage and transmission of genetic information. DNA spills from E. coli cell. Modern Biology Pages 193 - 195. Function of DNA. Genetic information must tell

chung
Download Presentation

DNA, RNA And Protein Synthesis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. DNA, RNA And Protein Synthesis

  2. Modern Biology Pages 193 - 195 Function of DNA • Structure of DNA must allow the storage and transmission of genetic information. DNA spills from E. coli cell.

  3. Modern Biology Pages 193 - 195 Function of DNA • Genetic information must tell • cell(s) how to make proteins. Proteins are made in the cytoplasm but DNA remains in nucleus

  4. Modern Biology Pages 193 - 195 Functions of DNA • Proteins form structures and control chemistry of cell. Ribosomes embedded in the E.R. construct proteins

  5. Modern Biology Pages 193 - 195 Functions of DNA • Structure of DNA must allow exact replication to occur.

  6. Why Understanding DNA is Important to You.

  7. Modern Biology Pages 193 - 195 DISCOVERY OF DNA – GRIFFITH’S EXPERIMENT • Called transformation. • Used mice and pneumonia. • Rough (non-virulent) • Smooth (virulent) Griffith’s Experiment

  8. Modern Biology Pages 193 - 195 Avery Determines DNA To Be Hereditary Molecule • Avery, McCloud, and McCarty • Used process of elimination. • Determined DNA was heredity material.

  9. Modern Biology Pages 184 - 187 Important People in DNA Science • Rosalind Franklin of Cal Tech in Los Angeles took pictures using X-Rays in the 1930’s Was never given due credit for her contribution to DNA Science

  10. Modern Biology Pages 184 - 187 Important People in DNA Science • James Watson & Francis Crick discovered structure of DNA in 1953. James Watson Left & Francis Crick right: Nobel prize for DNA structure

  11. Modern Biology Pages 184 - 187 DNA Structure • DNA is a polymer. • The monomer of DNA is called a nucleotide. deoxyribonucleic acid

  12. Modern Biology Pages 184 - 187 Nucleotide Structure • One 5 carbon sugar called deoxyribose. • “Deoxy” = one less oxygen. • “ribo” = than ribose. • Deoxyribonucleic acid • “nucleic” = found in nucleus. • “acid” = acidic Deoxyribose, a pentose sugar, has each carbon numbered.

  13. Modern Biology Pages 184 - 187 Nucleotide Structure Phosphate group attached to the #5 carbon of the sugar. The phosphoric acid is negative and so makes the DNA molecule negative. The deoxyribose has a nitorgenous base and a phoshate attached to it.

  14. Modern Biology Pages 187 - 189 Nucleotide Structure • One nitrogenous base attached to the #1 carbon in the sugar.. • Adenine (Purine) • Guanine (Purine) • Cytosine (Pyrimidine) • Thymine (Pyrimidine) Four bases of DNA

  15. Modern Biology Pages 187 - 189 DNA Structure • DNA molecule has shape of a double helix. • The sides are anti-parallel.

  16. Modern Biology Pages 187 - 189 DNA Structure • Nucleotides linked together form the sides of the DNA molecule. • Phosphodiester bond links phosphates and deoxyribose Each phosphate is linked to two sugar molecules.

  17. Modern Biology Pages 187 - 189 DNA Structure Complementary base pairing rules • Nitrogenous bases form “steps” or rungs of the helix. • Adenine (2 rings) is bonded with Thymine (1 ring) using 2 hydrogen bonds. • Guanine (2 rings) is bonded with Cytosine (1 ring) using 3 hydrogen bonds.

  18. Modern Biology Pages 187 - 189 CENTRAL DOGMA OF DNA DNA mRNA Protein DNA must send a message to ribosomes as to how a protein is to be produced. 2) DNA must replicate itself exactly prior to each cell division.

  19. Modern Biology Pages 187 - 189 Replication of DNA • Replication must: • Occur prior to every cell division. • Occur during “S” phase of interphase. • Result in two identical copies of the DNA molecule.

  20. Modern Biology Pages 187 - 189 Replication of DNA • DNA replication is semi-conservative • Each new molecule is composed of one old and one new strand.

  21. Modern Biology Pages 187 - 189

  22. Modern Biology Pages 187 - 189 Replication Process • Replication fork is where double helix is split apart. • Double helix is split apart by enzyme called DNA Helicase.

  23. Modern Biology Pages 187 - 189 Replication Process • Role of DNA polymerase. • Constructs a new strand of DNA • One side is continuous • One side is discontinuous • Complementary nature of bases allows replication to occur properly. • Replication occurs at many sites at same time.

  24. Modern Biology Pages 187 - 189 Replication Process • Mistakes and repair processes. • Xeroderma Pigmentosa • Lacks proper enzyme to repair DNA damage due to sunlight. • Multiple carcinomas develop due to exposure to uV light

  25. Modern Biology Pages 190 - 194 RNA • Structure of RNA. • Ribose instead of deoxyribose. • Uracil instead of thymine. • Single helix instead of double. • Three types of RNA. • mRNA • tRNA • rRNA RNA is made from DNA

  26. Modern Biology Pages 190 - 194 TRANSCRIPTION • Making mRNA as a messenger. • Process referred to as transcription. • Purpose is to copy the message for a protein from the DNA molecule. Making mRNA

  27. Modern Biology Pages 190 - 194 TRANSCRIPTION • Transcription • DNA untwists and unzips in area of molecule where the message for a certain protein is held. • Role of RNA polymerase. • Role of promoter. • Role of termination signal. Making mRNA

  28. Modern Biology Pages 190 - 194 TRANSCRIPTION • The product of transcription is mRNA, tRNA,and rRNA. • Transcription occurs in the nucleus of the cell.

  29. Modern Biology Pages 190 - 194 Translation • Translation occurs in the cytoplasm. • Amino acids are assembled polypeptides. (Proteins) • Ribosomes assemble polypeptides based on instructions held in the DNA molecule. mRNA leaving the nucleus

  30. Wednesday 1/8/03 Pages 194 - 198 Translation • Protein structure • Composed of building blocks called amino acids. • 20 different types of amino acids. • Sequence and length of amino acid chain determines the characteristics of the protein. Ribosomes attach to the mRNA molecule in the cytoplasm.

  31. Wednesday 1/8/03 Pages 194 - 198 Genetic code • The Genetic Code • Each 3 nucleotides on mRNA is a codon. • Each codon codes for a specific amino acid. • 64 possible codons. • 1 start codons • 3 stop codons • 60 different codons code for 20 different types of amino acids. mRNA codon list

  32. Wednesday 1/8/03 Pages 194 - 198

  33. Wednesday 1/8/03 Pages 194 - 198 Translation • The ribosome binds to the mRNA. • tRNA (with anticodon) brings proper amino acid to ribosome. (met tRNA) • Ribosome moves to next three bases (codon). • Another tRNA brings proper AA to ribosome. • Protein is assembled. • Stop codon signals end of protein. tRNA brings an amino acid to the ribosome.

More Related