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DNA and Genes

DNA and Genes

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DNA and Genes

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  1. DNA and Genes Chapter 11 pgs. 280-301

  2. Take out 1 sheet of paper and write both lab partners names on it. Discuss and answer the questions from the powerpointon the paper Textbook pg. 280 1. Pick one of the 3 bullet points under “What You’ll Learn” and explain what you think it means. 2. Why is DNA important? 3. Explain how the characteristics of the Shetland pony relate to its DNA?

  3.  History of DNA • 1800’s Mendel determined that offspring inherited traits from parents • 1944 Biomolecule that was involved with heredity was DNA (originally proteins were thought to pass on traits because DNA was too simple) • SCIENCE IS TENTATIVE

  4. Rosalind Franklin and Maurice Wilkins took diffracted photographs of DNA • X-rays were passed through DNA crystals, the X-rays were bent by the atoms in the DNA molecule producing an image of the shape

  5. 1953 Watson & Crick developed a model of DNA using the diffraction photographs • Double Helix = DNA comes in 2 long strands that wrap around each other, “spiral staircase”

  6. Textbook pg. 283 • Look at figure 11.2 (don’t forget to read the caption!) 4. What is another analogy used for the shape of DNA (besides a spiral staircase)?

  7.  Why is DNA so important? • DNA is known as “blueprint of life” • DNA contains instructions for making proteins within the cell • Genesare on our chromosomes, chromosomes are made of DNA

  8. Turn to page 281 • Read the paragraph with the heading What is DNA? 5. List 3 places in your body that contain proteins 6. Enzymes are a type of protein. Why do we need them?

  9. Why is DNA so important? • Important for all life on Earth, makes each individual plant or animal unique • Helps us understand diseases better & find potential cures • Better food crops

  10.  DNA Nucleotides • DNA is a nucleic acid made from subunits called nucleotides • Nucleotide = 3 parts: five-carbon sugar, phosphate group, nitrogenous base • Deoxyribose = the sugar in a DNA nucleotide

  11.  How the Double Helix stays together phosphates • Double Helix has two strands that twist together • One strand of DNA is like one half of a zipper • The backbone of the molecule is alternating phosphates and deoxyribose sugar • The teeth are nitrogenous bases deoxyribose bases

  12. One strand of DNA (half of a zipper) is a polymerof nucleotides • One strand of DNA has millions of nucleotides

  13.  Nitrogenous Bases • DNA has four different bases • Cytosine C • Thymine T • Adenine A • Guanine G

  14. 2 kinds of Nitrogenous Bases • Purines = double ring bases, A and G • Pyrimidines = single ring bases, T and C

  15.  Complementary Bases • Nitrogenous bases on the 2 strands of DNA pair up with one another • Cytosine pairs with Guanine with 3 (triple) Hydrogen Bonds • Adenine pairs with Thymine with 2 (double) Hydrogen Bonds

  16. Textbook pg. 283 Read the Problem-Solving Lab 11.1 Answer the 3 “Thinking Critically” questions. These will be questions numbered 7-9 on your paper.

  17.  DNA Model