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MODULE 2: SICKLE CELL DISEASE - Coggle Diagram
MODULE 2: SICKLE CELL DISEASE
Why is DNA the Genetic Material
How do We Know DNA Is the Genetic Material?
1920s: first experiment was done by Fredrick Griffith. He worked with two types of bacteria S strain (containing capsule), injected in mice that killed it, and R strain (lacked capsule), injected in mice but didn't kill it. Both heat killed S strain and R strained are injected in the mice and it died. He observed that th dead S strain was providing information to transform R strain into live S strain, which he calls a transforming factor.
Oswald Avery added DNase to Griffith's original experiment. It breaks down DNA and the transformation of R strain didn't occur and mice lived. He concludes that DNA is a genetic material.
1952: Alfred Hershey and Martha Chase used a virus called bacteriophage to firmly establish whether DNA or proteins were genetic material. Bacteria was injected with radioactive DNA, which was radioactive in the end of the experiment.
How is DNA Copied?
Why is DNA Replication Semiconservative?
after DNA is copied, new daughter molecule contains one template strand and newly synthesized complementary strand
Was determined by experiments of Mathew Meson and Franklin Stahl, who in 1958 used radioactivity labeled DNA to determine the principles of semi-conservative replication
On the leading strand: the DNA polymerase follows directly behind helices enzyme. On th lagging strand: DNA polymers makes short segments of DNA, called fragments, which are connected together by DNA Ligase enzyme
Identical sister chromatids are the end results of DNA replication. These will be separated and sent to each new cell during cell division
How is DNA Replicated?
Helices breaks the hydrogen bonds between the complementary paired base nucleotides in each strand
DNA polymerase synthesize new strand of DNA using separate strands as templates
What is Polymers Chain?
consist of 3 basic steps: Denaturation, Annealing, Extension
Denaturation (95 degrees C): DNA is heated and single stranded. Replaces helices in DNA replication
Annealing (50 - 60 degrees C): primer binds to a single DNA strand. The primer was designed to specifically target a short segment of the DNA molecule
Extension (72 degrees C): DNA Polymerase adds complementary bases to each single DNA strands, creating double stranded DNA.
Called a chain reaction because DNA is repeatedly replicated, creating billions of copies of just 30-45 cycles
What is Gene Expression?
What is the Purpose of Gene Expression?
Gene Expression is the series of events within a cell that takes information within the DNA and produce the protein molecule
Two challenges: DNA information is in different language and DNA and protein synthesis machinery is located in different locations within the cell
Transcription and Translation addresses the problems
Transcription converts genetic information into intermediary RNA molecule called messenger RNA (mRNA)
Translation interprets genetic information, from the mRNA, into a structure of a protein