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WorksheetsIB Biology - Topic 7.1: DNA Structure and Replication
Total questions: 9
Worksheet time: 2hrs 47mins
Overview of Hershey-Chase Experiment (to figure out if it was the protein coat or the nucleic acid which contained genetic info)
2 different solutions: one with radioactive 35S which affected the protein coat, the other with 32P which affected NA
the dna was injected into the bacteria by the virus, then it was blended to separate and then centrifuged
the radioactive component 32P was the genetic info, which was found in the pellet, the other was found in the supernatant
what did xray diffraction reveal about the shape of dna?
the double helical nature
the angle of the helix
the complementary base pairing
What is DNA topoisomerase?
relieves tension
prevents coiling
the second step in dna replication
splices dna
DNA helicase
first enzyme in replication
unwinds the dna at replication fork
removes primers, replaces with nucleotides
prevents annealing
RNA Primase
step 4 in dna replication
places RNA primers on the leading strand and multiple on the lagging strand.
prevents annealing
places nucleotides
DNA Polymerase III
places DNA nucleotides continuously on leading strand
places DNA nucleotides in short sections on lagging strand
the 4th step in dna replication
removes primers and replaces with nucleotides
DNA Polymerase I
removes primers and replaces with nucleotides
the 5th step
places RNA primers
unwinds and opens the dna at the replication fork
DNA Ligase
acts as glue by connecting all the fragments by creating bonds
step number 6
places dna in short sections (okazaki fragments)
step number 4
What are telomeres
the non coding region of dna
protect the ends of the chromosomes
the enzyme that initiates telophase
