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Bell warm up

Bell warm up. What is DNA? What do you know about DNA? What does it do? Draw DNA?. Engage. Spiderman X- men X-men more. DNA. Deoxyribonucleic Acid. The Structure of DNA. DNA function. DNA is often called the blueprint of life- stores genetic information

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Bell warm up

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  1. Bell warm up What is DNA? What do you know about DNA? What does it do? Draw DNA?

  2. Engage • Spiderman • X- men • X-men more

  3. DNA Deoxyribonucleic Acid

  4. The Structure of DNA

  5. DNA function • DNAis often called the blueprint of life- stores genetic information • In simple terms, DNA contains the instructions for making proteins within the cell.

  6. DNA- Double helix structure • Francis Crick and James Watson made the DNA double helix model in 1953.

  7. Why do we study DNA? We study DNA for many reasons, e.g., • its central importance to all life on Earth- DNA is present in all living things • medical benefits such as cures for diseases, • better food crops.

  8. Our genes are on our chromosomes. Chromosomes are made up of a chemical called DNA. Chromosomes and DNA

  9. The Shape of the Molecule • DNA is a very long polymer. • The basic shape is like a twisted ladder or zipper. • This is called a double helix.

  10. The Double Helix Molecule • The DNA double helix has two strands twisted together. • (In the rest of this unit we will look at the structure of one strand.)

  11. Question Why is DNA described as a double helix ?

  12. Question Why is DNA described as a double helix ?

  13. Answer DNA looks like a twisted ladder or a zipper

  14. One Strand of DNA phosphate • The backbone of the molecule is alternating phosphate and deoxyribose, a sugar, parts. • The teeth are nitrogenousbases. deoxyribose bases

  15. Nucleotides DNA is made up of units called nucleotides. consists of: Deoxyribose sugar Phosphate Nitrogenous base

  16. O -P O O -P O O -P O O O O O O O C C ribose ATP Nucleotides Nitrogenous base One deoxyribose together with its phosphate and base make a nucleotide. O Phosphate C C C Deoxyribose O

  17. One Strand of DNA nucleotide • One strand of DNA is a polymer of nucleotides. • One strand of DNA has many millions of nucleotides.

  18. Four nitrogenous bases DNA has four different bases: • Cytosine C • Thymine T • Adenine A • Guanine G

  19. Important: Adenine and Thymine always join together A T Cytosine and Guanine always join together C G

  20. N N C N C C C N N C Two Kinds of Bases in DNA N • Pyrimidines are single ring bases. • Purines are double ring bases. N C O C C N C

  21. N O N N C C O C C O C C C N C N C thymine cytosine Thymine and Cytosine are pyrimidines • Thymine and cytosine each have one ring of carbon and nitrogen atoms.

  22. O N N N C C N C C C C N N N C N C C Guanine Adenine C N N Adenine and Guanine are purines • Adenine and guanine each have two rings of carbon and nitrogen atoms.

  23. Two Stranded DNA • Remember, DNA has two strands that fit together something like a zipper. • The teeth are the nitrogenous bases but why do they stick together?

  24. N O N C N C O C C N C C N N C N C C N Hydrogen Bonds • The bases attract each other because of hydrogen bonds. • Hydrogen bonds are weak but there are millions and millions of them in a single molecule of DNA. • (The bonds between cytosine and guanine are shown here.)

  25. O N C O C C C N C N N C C C N N C C N Hydrogen Bonds, cont. • When making hydrogen bonds, cytosine always pairs up with guanine, • And adenine always pairs up with thymine. • (Adenine and thymine are shown here.)

  26. Important: Adenine and Thymine always join together A T Cytosine and Guanine always join together C G

  27. The earth is 150 billion m or 93 million miles from the sun. DNA by the numbers • Each cell has about 2 m of DNA. • The average human has 75 trillion cells. • The average human has enough DNA to go from the earth to the sun more than 400 times. • DNA has a diameter of only 0.000000002 m.

  28. Notes • DNA is double stranded • looks like a twisted ladder or zipper • Carries genetic information • Watson and crick made the first 3-d model • AT • GC

  29. Question 1. Adenine pairs with _______ 2. Cytosine pairs with _______

  30. Question A nucleotide consists of: a. _____________ • _____________ • _____________

  31. DNA book cover p 6 nucleotides on each strand 12 nucleotides total on first page p S A T p p S G C S p p C S G S p p S C G S p p A T S S

  32. DNA book cover ---Back page • More facts about DNA (at least 2) • DNA timeline ( pg 292-293)

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