Biol 141 Nucleic Acids and Central Dogma Notes

Nucleic acids and Central Dogma

 Frederick Griffith
o EXPERIEMNT
 Take living virulent bacterial and inject into mouse
 Mouse dies
 Takes living non-virulent bacteria and inject into mouse
 Mouse is alive
 Boils living virulent bacteria, dies
 Injects that bacteria into the mouse
o Mouse alive
 Mixing dead virulent and living non-virulent and mixes them
 Mouse dies
 CONCLUSION
 Something from the dead virulent changes the living non-virulent and
telling it to become virulent (deadly)
 50% dry mass of cells is PROTEINS
 Most people at the time thought proteins was the genetic info causing
this change
 Avery, MacLeod, and McCarty
o EXPERIMENT
 Trying to figure out what molecule is transforming
 Do the same 4 groups as Griffith
 2 more groups
 Adding enzyme that destroys DNA
o DNase e(-ase means enzyme)
o RESULT: alive mouse
 Adding enzyme that destroys protein
o Protease
o RESULT: dead mouse
 CONCLUSION: not blocked when proteins destroyed, but could not become
virulent if DNA was destroyed
 DNA providing genetic information
 Chase-Hershey
o EXPERIMENT
 Showed DNA as genetic material
 Used viruses called bacteriophages
 Infect bacteria
 inject some material being injected that carries information needed for
bacteria to produce new bacteriophage
 what material injected? Protein or DNA
 radioactively labeled DNA or PROTEIN
 DNA
o Radioactivity is now in bacteria

,  PROTEIN
o Radioactivity left with the phage
 CONCLUSION: DNA was the genetic information
 Components of nucleotide monomers
o BOTH DNA and RNA
 3 parts
 Phosphate
 Sugar
 Nitrogenous base
o Sugar
 1:2:1 ration of C, H, O
 CH2O
 Most names end in -ose
 5C sugars in nucleotide (pentose)
 In RNA
o Ribose
 Has OH group on the 2 C (counting clockwise in ring)
 In DNA
o Deoxyribose
 Has H group on 2 C (counting clockwise in ring)
 MISSING O on 2 C
o Phosphate group
 Always attached to C5 of pentose sugar
 Counting clockwise in ring
 Similar between RNA and DNA
 Monomers
 Can have 1-3 phosphates on the 5’ C
o Nitrogenous base
 Connected to 1’ C of sugar
 2 types
 Pyrimidines
o C, U, and T
o One ring
 Purines
o A and G
o 2 rings
 Determines the identity of the nucleotide!!!!
 Uracil in place of thymine in RNA ONLY
 Polynucleotides
o Dehydration reaction
o Nucleotide monomers connected by phosphodiester bonds
o Form bond with 3’ C
o ALWAYS connect incoming nucleotide to the 3’C
o OH and H leftover give us water!!