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Do Now. Why is it important to learn about DNA and how can DNA be used to help people? NUA Notebook Check Today. Unit 4 Genetics. Ch. 12 DNA & RNA. Topic: The Components & Structure of DNA. Genes were known to do 3 specific things: Carry info. from 1 generation to the next

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Do Now

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  1. Do Now • Why is it important to learn about DNA and how can DNA be used to help people? • NUA Notebook Check Today

  2. Unit 4 Genetics Ch. 12 DNA & RNA

  3. Topic: The Components & Structure of DNA • Genes were known to do 3 specific things: • Carry info. from 1 generation to the next • Put that info. to work by determining heritable characteristics of organisms • Be easily copied, since all of a cell’s genetic info. is replicated every time a cell divides

  4. The Components & Structure of DNA • DNA is a long molecule made up of units called nucleotides • Nucleotides - made up of 3 parts: • A sugar • A phosphate group • A nitrogenous base

  5. The Components & Structure of DNA • Watson & Crick developed the model of DNA, a double helix, where 2 strands were wound around each other

  6. The Components & Structure of DNA • The 2 strands of DNA are held together by hydrogen bonds • Those bonds only link adenine (A) & thymine (T), & guanine (G) & cytosine (C) • Base-pairing rule - A - T, G - C

  7. Structure of DNA

  8. BUILD A DNA MOLECULE • USING THE COLORED STICKS CREATE A DNA MOLECULE USING THE BASE PAIRING RULES. EACH STICK HAS A NUCLEOTIDE LETTER WRITTEN ON ONE SIDE OF THE STICK. A = T C = G ATGC = ORIGINAL STRAND CREATE NEW STRAND

  9. COMPLETE WORKSHEET DNA AND RNA • 12-1 WORKSHEET PAGE 287 TO 294 (textbook required)

  10. Homework Chapter 12 Vocabulary: Pages 287 and 295 Use online textbook or internet to complete

  11. DO NOW • WHAT ARE THE COMPLIMENTARY DNA BASES TO THE THIS GENETIC CODE? • HINT: USE NITROGEN BASE PAIRING RULES A-T-T-G-G-C-A

  12. DNA & Chromosomes • Most prokaryotes have a single circular DNA molecule in their cytoplasm

  13. DNA & Chromosomes • Eukaryotic DNA is located in the nucleus, in the form of a # of chromosomes • The chromosome # varies from 1 species to another

  14. DNA & Chromosomes • Eukaryotic chromosomes have both DNA & protein, packed tightly together to form chromatin • Chromatin - DNA that is tightly coiled around proteins (histones)

  15. DNA & Chromosomes • From largest to smallest, genetic information is arranged the following way: • Chromosomes • Genes (found on chromosomes) • DNA (makes up genes)

  16. DNA Replication • Each strand of DNA could be used to make the other strand, they compliment each other • Replication - when a cell’s DNA is copied

  17. DNA Replication • During DNA replication, the DNA molecule separates into 2 strands, then produces 2 new complimentary strands following base pairing rules • Each strand of the double helix serves as a template, or model, for the new strand

  18. DNA Replication • DNA polymerase - enzyme that joins individual nucleotides to produce a DNA molecule • It also proofreads each new DNA strand, to help prevent errors in copying the DNA

  19. DNA Replication

  20. AGENDA • COMPLETE DNA REPLICATION WORKSHEET. (QUIZ) • FINISH WORKSHEET FROM YESTERDAY HOMEWORK VOCABULARY ON PAGE 300

  21. RNA & Protein Synthesis • Genes - coded DNA instruct. that control the production of proteins within the cell • The 1st step in decoding the genetic messages is to copy part of the nucleotide sequence from DNA into RNA

  22. Do Now (Replication) • Using the genetic code given, separate the two original strands and create two molecules of DNA. Use the base pairing rules. (hint: what you did on your quiz) A-T-C-C-G-T-A-C-G T-A-G-G-C-A-T-G-C

  23. The Structure of RNA • There are 3 main differences between RNA & DNA: • The sugar is a ribose, instead of deoxyribose • RNA is single-stranded • RNA contains the nitrogenous base uracil (U) instead of thymine (T)

  24. Types of RNA • There are 3 main types of RNA: • Messenger RNA • Ribosomal RNA • Transfer RNA

  25. Types of RNA • Messenger RNA - (mRNA) - RNA molecules that carry copies of instructions for assembling amino acids into proteins • They serve as “messengers” from DNA to the rest of the cell

  26. Types of RNA • Ribosomal RNA - (rRNA) - form of RNA that combines with proteins to make a ribosome

  27. Types of RNA • Transfer RNA - (tRNA) - RNA molecule that transfers each amino acid to the ribosome as it is specified by coded messages in mRNA

  28. Agenda • Complete worksheet on 12-2 (use textbook) • 12-2 Assessment page 299 questions 1 through 5 • Homework Compare and contrast the three types of RNA (Venn Diagram)

  29. Do Now What do all forms of RNA have in common? mRNA rRNA tRNA PAGE 300 TEXTBOOK

  30. Types of RNA • Transcription - process of producing RNA molecules by copying part of the nucleotide sequence of DNA into a complimentary sequence of RNA • RNA polymerase - enzyme that works similarly to DNA polymerase

  31. Types of RNA • During transcription, RNA polymerase binds to DNA & separates the DNA strands • RNA polymerase then uses 1 strand of DNA as a template to assemble nucleotides into a strand of RNA

  32. Transcription

  33. The Genetic Code • Proteins are made by joining amino acids into long chains - polypeptides • Each polypeptide has a combination of any 20 different amino acids

  34. The Genetic Code • Codon - 3 consecutive nucleotides that specify a single amino acid to be added to the polypeptide

  35. The Genetic Code • For ex.: • UCGCACGGU • Read 3 at a time: • UCG-CAC-GGU • Which represents amino acids: • Serine-Histidine-Glycine

  36. The Genetic Code

  37. Agenda • Quick Lab page 303 How does a • cell interpret DNA? • Complete worksheet on 12-3 • Homework: Vocabulary 307 • Chapter 12 Test on Thursday

  38. Do Now Using your textbook page 303 (genetic code) the mRNA codons from left to right, write the amino acid sequence of the polypeptide translated from the mRNA. GATCCTTCCAACATC

  39. Translation • Translation - (protein synthesis) -decoding an mRNA message into a polypeptide chain (protein) • It takes place on ribosomes • Before translation occurs, mRNA is transcribed (re-written) from DNA in the nucleus & released in the cytoplasm

  40. Translation • Each tRNA molecule has an anticodon - 3 nitrogenous bases that are complimentary to 1 mRNA codon • The ribosome attaches 1 amino acid to another, forming the polypeptide chain, until it reaches the “stop” codon

  41. Translation • After the amino acid is attached, the tRNA molecule that brought it into the ribosome, is released back into the cytoplasm • The result is a protein

  42. Translation

  43. Translation

  44. Summary: Role of RNA & DNA • Start with a single strand of DNA • That DNA is transcribed into RNA • The RNA is separated into codons • The codons code for amino acids, which form a polypeptide chain

  45. Mutations • Mutations - a mistake in the DNA base sequence, may occur during copying the DNA • Changes in the genetic material

  46. Kinds of Mutations • Gene mutations are changes in a single gene • Chromosomal mutations are changes in the whole chromosome

  47. Gene Mutations • Point mutations - change in 1 or a few nucleotides, they occur at a single point in the DNA sequence • Frameshift mutations - adding or deleting a nucleotide, shifts the “reading frame” of the genetic message

  48. Chromosomal Mutations • There are 4 types of chromosomal mutations: deletions, duplications, inversions, & translocations • Deletions involve the loss of all or part of a chromosome • Duplications produce extra copies of parts of a chromosome

  49. Agenda • Worksheet (complete both sides) use textbook page 303 genetic code to write amino acid sequence. • 12-3 Section Assessment 1 through 4 • Vocabulary page 309

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