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Thursday 3/13 WARM UP!!!!  (USE CHAPTER 6 SECTION 1 TO find the answers!!!)  1. What is a nucleotide?  2. ___________ is a molecule that is present.

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Presentation on theme: "Thursday 3/13 WARM UP!!!!  (USE CHAPTER 6 SECTION 1 TO find the answers!!!)  1. What is a nucleotide?  2. ___________ is a molecule that is present."— Presentation transcript:

1 Thursday 3/13 WARM UP!!!!  (USE CHAPTER 6 SECTION 1 TO find the answers!!!)  1. What is a nucleotide?  2. ___________ is a molecule that is present in all living cells that contains the information and determines the traits that a living thing inherits.

2 1. What Does DNA Look Like?  The Pieces of the Puzzle-Scientists knew genes must be able to do two things  1) must be able to give instructions for building and maintaining cells.  2) It must be able to be copied each time a cell divides so each cell must contain identical genes.

3  1 ) DNA is made of subunits called nucleotides- a subunit that consists of a sugar, a phosphate, and a nitrogen base.  2) There are 4 different bases-adenine, thymine, guanine, and cytosine - each base has a different shape  3) adenine connects to thymine; guanine connects to cytosine 2. Nucleotides: The Subunits of DNA

4 3. Chargaff’s Rule  Rule-amount of adenine always equals thymine; the amount of guanine always equals cytosine.  -this later helped scientists understand DNA

5 4. Rosalind Franklin’s Discovery  Rosalind Franklin used X-ray diffraction to make images of DNA molecules. X rays are aimed at the DNA molecule. When an X ray hits a part of the molecule the ray bounces off. They saw it was spiral shaped.

6 5. Watson and Crick’s Model-  After seeing Franklin’s images they decided it must look like a long, twisted ladder. They built a model of DNA which explained how it functions in the cell.

7 6. DNA’s Double Structure-  Known as a double helix; sides always alternate between sugar and phosphate; the rungs of the ladder are always made of two bases.

8  DNA-pairing of the bases allows cell to replicate 7. Making Copies of DNA

9 8. How Copies of DNA are made 1.DNA splits down the middle where the bases meet 2.bases on each side of the molecule are used as a pattern for a new strand 3.as bases are exposed; complementary nucleotides are added to each side of the ladder. 4.DNA molecules are formed (half of each molecule is old and half is new)

10 1.DNA is copied every time a cell divides 2.Each gets a complete set of DNA 3.Unwinding, copying, and rewinding is done by proteins 9. When Copies Are Made

11  What does DNA stand for?  If I gave you the Gene sequence TAACG, what would be the complementary side of the double helix? How about GCTAAGGC PRACTICE

12  DNA stands for: Deoxyribonucleic acid (You need to know this!)  The complementary bases for TAACG  Would be…ATTGC  GCTAAGGC  Would be CGATTCCG  WHY???? Because of Chargaff’s Rule… Adenine and Thymine & Cytosine and Guanine REMEMBER THIS!!!(A&T… ALWAYS TOGETHER and C & G… THE WAY TO BE!) PRACTICE ANSWERS

13  BE SURE YOUR Ch. 6 VOCAB IS FINISHED AND HAS BEEN CHECKED OFF BY ME!  YOUR OUTLINES ARE ALSO DUE!  I would like you to write your intro paragraph for me to look over  Complete Ch. 6 Notes (From Thurs 3/6)  THEN… work on HW… Ch. 6.1 Review SCIENCE TODAY


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