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DNA: THE ALAPHABET OF LIFE

DNA: THE ALAPHABET OF LIFE. REMEMBER CYTOLOGY--the study of cells. the nucleus ... ... is the control center ... ... which has the genetic material ... ... which is DNA ( deoxyribonucleic acid ) * lots of DNA when it is bunched up is called a chromosome CHROMOSOMES = LOTS OF DNA.

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DNA: THE ALAPHABET OF LIFE

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  1. DNA: THE ALAPHABET OF LIFE

  2. REMEMBER CYTOLOGY--the study of cells the nucleus ... ... is the control center ... ... which has the genetic material ... ... which is DNA(deoxyribonucleic acid) * lots of DNA when it is bunched up is called a chromosome CHROMOSOMES = LOTS OF DNA

  3. What’s So Special About DNA? • DNA stores and passes on genetic information from one generation to the next. • DNAis often called the blueprint of life • In simple terms, DNA contains the instructions for making proteins within the cell.

  4. Why do we study DNA? • its central importance to all life on Earth, • medical benefits such as cures for diseases, • better food crops http://learn.genetics.utah.edu/content/begin/tour/

  5. Chromosomes and DNA • Chromosomes are made up of many genes. • Genes are sequences of DNA that code for a Protein.

  6. DNA • Discovery of the DNA double helix • 1950’s • Rosalind Franklin-X-ray photo of DNA. • Watson and Crick-described the DNA molecule from Franklin’s X-ray.

  7. What is DNA? • Deoxyribonucleic Acid • Made up of nucleotides in a DNA double helix. • Nucleotide: • Phosphate group • 5-carbon sugar • Nitrogenous base • Interactive

  8. DNA DNA is Made of Two Long Chains of Nucleotides Nucleotide Hydrogen bonds Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G) G and C are complementary as are A and T

  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. DNA STRUCTURE • The outer parts (sides) of the ladder are made of sugar and phosphate • The steps (rungs) of the ladder are made of pairs of nitrogenous bases.

  11. 4 Nitrogenous Bases • ADENINE = A • GUANINE = G • CYTOSINE = C • THYMINE = T Complementary Base Pairing: • Adenine pairs with Thymine • Guanine pairs with Cytosine

  12. O N N O N N N N C C C C N O C C C C O C C C C C N N N N C C N N C C thymine cytosine C Guanine Adenine C N N Two Kinds of Bases in DNA • Pyrimidines are single ring bases. • Thymine and Cytosine • Purines are double ring bases • Adenine and Guanine

  13. DNA Structure • Remember, DNA has two strands that fit together something like a zipper. • What holds the nitrogenous bases together? • The bases attract each other because of hydrogen bonds.

  14. DNA STRUCTURE • The combinations of nitrogenous bases form the codes that produce that genes for particular traits. • Because there can be so many different combinations of the bases, the code can be limitless. Video

  15. DNA Structure • DNA makes up genes • Examples of genes: • ATCGTCAGG may be for hair color BUT • ATCGTCAGC may be for eye color

  16. Interactive • Interactive • Tim and Moby

  17. DNA REPLICATION • Replication is the process where DNA forms exact copies. • Complementary Base Pairing allows each strand of DNA to serve as a template for DNA replication

  18. DNA REPLICATION • The DNA unwinds • The ladder unzips • Free floating nitrogen bases begin to pair with each strand. • Two new DNA chains are formed.

  19. DNA Replication – Something Old and Something New In Each Daughter Molecule Video Interactive

  20. Simple as it is in principle, DNA replication requires many enzymes that work together • Example: DNA polymerase

  21. Quiz • List the following in order from smallest to largest: Cell, DNA, Chromosome, Gene, Nucleus. • Describe the structure of DNA. • What are nucleotides made of? • After replication, how do the daughter molecules compare to each other? How do the strands of each daughter molecule compare? • Given the sequence: ATGGCAACGTTA, what is the complementary sequence?

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