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DNA and RNA

DNA and RNA. Lab Biology. DNA (Deoxyribonucleic Acid) Structure. DNA is a nucleic acid- all nucleic acids are polymers of nucleotides DNA is a macromolecule Nucleotides are made up of three parts: Phosphate group Nitrogenous base 5-carbon sugar- deoxyribose.

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DNA and RNA

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  1. DNA and RNA Lab Biology

  2. DNA (Deoxyribonucleic Acid) Structure • DNA is a nucleic acid- all nucleic acids are polymers of nucleotides • DNA is a macromolecule • Nucleotides are made up of three parts: • Phosphate group • Nitrogenous base • 5-carbon sugar- deoxyribose

  3. DNA (Deoxyribonucleic Acid) Structure • DNA is made up of four different types of nucleotides, each containing a different nitrogenous base: • Adenine • Cytosine • Guanine • Thymine

  4. DNA (Deoxyribonucleic Acid) Structure • You can think of the sequence like this: Macromolecules Nucleic acids DNA Nucleotide Sugar-phosphate backbone Nitrogenous bases Adenine, Cytosine, Guanine, and Thymine

  5. Chargaff’s Rules • Erwin Chargafffound that: • Adenine (A) always pairs with Thymine (T) • Cytosine (C) always pairs with Guanine (G)

  6. Experiments Leading to the Discovery of DNA • In 1928, Frederick Griffith injected mice with different samples of pneumonia causing bacteria, smooth, deadly bacteria and rough harmless bacteria

  7. Experiments Leading to the Discovery of DNA • He found that some molecule or group of molecules had changed the harmless rough bacteria into deadly smooth bacteria- he called this transformation

  8. Experiments Leading to the Discovery of DNA • In 1944, Oswald Avery believed that if he found out which molecule was needed for transformation to occur, he might be able to identify the molecule that makes up genes

  9. Experiments Leading to the Discovery of DNA • Avery reached the conclusion the genes are made of DNA because transformation was blocked when he destroyed the molecule of deoxyribonucleic acid

  10. Experiments Leading to the Discovery of DNA • In 1952, Martha Chase and Alfred Hershey used radioactive isotopes to label the DNA and proteins of certain viruses, they concluded that the genetic material of a virus was DNA and not the protein

  11. Experiments Leading to the Discovery of DNA • In 1953, James Watson and Francis Crick discovered that the structure of the DNA molecule is a double helix (2-strands), they used Rosalind Franklin’s X-ray work on DNA to come to this conclusion

  12. Experiments Leading to the Discovery of DNA • Watson and Crick found that hydrogen bonds between the nitrogenous bases in a base pair, (A and T, C and G) were what held the two strands of DNA together

  13. Experiments Leading to the Discovery of DNA • Thus the sequence on one strand is matched perfectly to a complementary sequence on the other strand

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