HL Nucleic Acid Flashcards
Who and how did they prove that DNA is genetic material?
Hershey and Chase proved by radioactively labeling the proteins of the virus with sulfur (S32), and DNA with phosphorus
(P23). The Virus infected the bacteria and caused bacteria to form a solid pellet while smaller viruses remained in the supernatant. The Bacteria pellet was found to be radioactive when infected by the P23 Virus (one with phosphorus).
Who and how did they find the structure of DNA?
Franklin and Chargaff, by using an X-ray and seeing how the x-ray beam diffracted.
Describe the structure of DNA
DNA is a double-stranded helical molecule with Nitrogenous bases that are packed together on the inside and phosphates form an outer backbone.
How does semi-conservative DNA replication take place and their functions?
DNA Helicase separates double-stranded DNA by break hydrogen bonds.
DNA Gyrase reduces the stress created when unwinding DNA by Helicase
Single-stranded binding proteins prevent the strands from re-annealing.
DNA Primase makes an RNA sequence, makes the primer.
DNA Polymerase III align free nucleotides and join them. Since DNA is antiparallel, DNA III on the leader strand synthesis continuously while DNA III on lagging strand synthesis in pieces
DNA Polymerase I Removes primers and replaces them with DNA Nucleotide.
DNA Ligase joins the Okazaki fragments together to form a continuous strand. By joining sugar-phosphate backbones together with the phosphodiester bond.
How is DNA sequenced?
PCR, put into test-tubes with A’, T’, C’, G’
makes fragments due to free nucleotides and dDNA.
Electrophoresis to find complementary base pairs.
Why can’t nucleotides form after dDNA attaches?
Cannot form a bond with the 3’ Carbon from the dDNA because it can’t be bonded with the phosphate.
