DNA and RNA

• Chromosomes


  Tightly coiled strands of DNA, different organisms have different numbers of chromosomes

  
• Genes


  A piece of DNA that has instructions to code for one protein, one chromosome can contain thousands of genes linked together
• Nucleic Acids


  A macromolecule that carries our genetic material (DNA), contain genes - the blueprint/instructions for making proteins, located at certain points in a chromosome, proteins carry out all cellular activity, two types: DNA and RNA
• Nucleotides


  Make up nucleic acids (the monomer), have three parts: sugar, phosphate, and nitrogen base

  
• Phosphodiester bond is between phosphate group and the deoxyribose, Glycosidic bond is between deoxyribose and the nitrogen base

  
• DNA structure


  • Double stranded double helix with right handed twist, major groove occurs where the backbones are far apart, minor groove occurs where they are close together, approximately 10 bases per turn, the sugar in DNA is DEOXY RIBOSE and the sugar in RNA is Ribose, nitrogenous bases make up the core/middle of the DNA, connected by hydrogen bonds, sugar phosphate backbone and nitrogenous bases

  
• DNA base pairing rules

  Nitrogen bases bond only to their complementary base pair with hydrogen bonds, A's bond with T's, C's bond with G's
• Nitrogen Bases


  Purines (Adenine, Guanine) and Pyrimidines (Cytosine, Thymine, Uracil)
• Chargaff's rules state that in any species there is an equal number of A and T bases, and an equal number of G and C bases
• Hydrogen Bonds


  There are 2 hydrogen bonds between Adenine and Guanine while 3 hydrogen bonds between Cytosine and Thymine, G-C are responsible for the stability of the DNA, more the G-C, more stable the DNA is
• DNA shows antiparallel orientation, the strands run in opposite or antiparallel directions
• RNA Structure


  Single strand of nucleotides with exposed bases, RNA bases bind with DNA bases (A's bind with U's, C's bind with G's)

  
• Types of RNA


  • Messenger RNA, Ribosomal RNA, Transfer RNA
• DNA is made up of a sugar phosphate backbone and nitrogenous bases, the nitrogenous bases are classified into purines and pyrimidines, adenine and guanine are purines and they are double ringed while cytosine, thymine and uracil are pyrimidines and they are single ringed structures

  
• Rosalind Franklin took x-ray pictures of DNA, first to show the shape was a double helix, called image 51, Watson, Crick, & Wilkins were awarded a Nobel Prize because they were the first to make a model of the double helix shape, Chargaff did experiments to come up with the base pairing rules (A-T, C-G)

  
• When a cell is ready to divide, it must first copy its DNA, the process of making an identical copy of DNA is called DNA Replication
• DNA Replication


  Enzyme Helicase unzips the DNA into two strands, Enzyme DNA Polymerase adds complementary nucleotides to the template strands, Two identical DNA molecules are formed, each with an "old" strand and a "new" strand (Semi-Conservative Replication)
• Primase


  Required for DNA synthesis, makes short RNA primers
• DNA polymerase


  Adds nucleotides to RNA primer, removes RNA primer and replaces it with DNA, proofreads the strand before the backbone is finished
• DNA ligase


  Seals the gaps in DNA, connects DNA pieces by making phosphodiester bonds
• Leading strand


  NEW strand made toward the replication fork
• Lagging strand


  NEW strand synthesis away from replication fork, replicates discontinuously, creates Okazaki fragments, Okazaki fragments joined by DNA ligase
• Two identical DNA molecules are formed, each with an "old" strand and a "new" strand, this is called Semi-Conservative Replication
• Meselson and Stahl's experiment supported the semi-conservative model of DNA replication
• Chromosomes


  Tightly coiled strands of DNA, different organisms have different numbers of chromosomes
• Genes


  A piece of DNA that has instructions to code for one protein, one chromosome can contain thousands of genes linked together
• Nucleic Acids


  A macromolecule that carries our genetic material (DNA), contain genes - the blueprint/instructions for making proteins, located at certain points in a chromosome, proteins carry out all cellular activity, two types: DNA and RNA

  
• Nucleotides


  Make up nucleic acids (the monomer), have three parts: sugar, phosphate, and nitrogen base

  
• Phosphodiester bond is between phosphate group and the deoxyribose, Glycosidic bond is between deoxyribose and the nitrogen base

  
• DNA structure


  • Double-stranded double helix with right-handed twist, major groove occurs where the backbones are far apart, minor groove occurs where they are close together, approximately 10 bases per turn
• DNA base pairing rules

  Nitrogen bases bond only to their complementary base pair with hydrogen bonds, A's bond with T's, C's bond with G's
• Nitrogen Bases


  Purines (Adenine, Guanine) and Pyrimidines (Cytosine, Thymine, Uracil)
• Chargaff's rules state that in any species there is an equal number of A and T bases, and an equal number of G and C bases
• Hydrogen Bonds


  There are 2 hydrogen bonds between Adenine and Guanine while 3 hydrogen bonds between Cytosine and Thymine, G-C are responsible for the stability of the DNA, more the G-C, more stable the DNA is
• DNA shows antiparallel orientation, the strands run in opposite or antiparallel directions
• RNA Structure


  Single strand of nucleotides with exposed bases, RNA bases bind with DNA bases (A's bind with U's, C's bind with G's)

  
• Types of RNA


  • Messenger RNA, Ribosomal RNA, Transfer RNA
• DNA is made up of a sugar phosphate backbone and nitrogenous bases, the nitrogenous bases are classified into purines and pyrimidines, adenine and guanine are purines and they are double ringed while cytosine, thymine and uracil are pyrimidines and they are single ringed structures

  
• DNA Discovery


  • Griffith's experiment, Avery's experiment, Hershey and Chase's experiment
• Rosalind Franklin took x-ray pictures of DNA, first to show the shape was a double helix, called image 51, Watson, Crick, & Wilkins were awarded a Nobel Prize because they were the first to make a model of the double helix shape, Chargaff did experiments to come up with the base pairing rules (A-T, C-G)