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15 Cards in this Set
- Front
- Back
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Draw Structure of Phosphate and Sugar and where base attaches.
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n/a
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What are the three experiments that led to the conclusion that DNA is the genetic material?
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1. Griffith assay for transformation
2. Avery, MacLeod & McCarty use the assay to purify the transforming principle (DNA) 3.Hershey & Chase use bacteriophage to provide further proof that DNA is the genetic material |
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What are the two pneumococcus types?
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rough and smooth. Smooth is virulent and rough is not. Smooth has a polysaccharide coat and rough does not.
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Explain Griffith's assay for transformation:
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living virulent in mouse-> dead
living non virulent in mouse-> alive dead virulent in mouse->alive dead virulent and live nonvirulent mix->dead why is this? there must be transformation |
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Describe the Avery, MacCleod and McCarty experiment:
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1. Take heat killed S virulent cells without lipids and carbs
a. sample includes no protein b. sample includes no RNA c. sample includes no DNA 2. Add R cells, and S cells appear in the samples with no Protein and RNA and add R cells to the sample with no DNA and no S cells appears so: transformation can not happen unless DNA is present, and DNA must be the hereditary material |
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What is a phage made up of?
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The phage genome is DNA and the body is protein.
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How are phages replicated?
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1. phage attaches to e. coli and injects chromosomes
2. bacteria chromosome breaks down and phage chromosome replicates 3. expression of phage gene makes the chromosomes assemble into new phage packages 4. wall of bacteria lyses and baby bacterias emerge |
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Which part of the phage is responsible for the transforming to phage progeny?
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see igure
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What did Hershey and Chase discover?
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It is the DNA, not protein that transmits information in a bacteriophage. One tube protein active one has DNA, only the one with DNA has radioactive phage babies
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Draw a nucleotide:
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see figure one: must include phosphate, sugar and base
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What is Chargaff's Ratio?
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the relationship between A/T G/C and (A+G)/(T+C) is ONE
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How does crystallography work?
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There is an x ray source that goes through a lead screen where crystals of a substance are bombarded and diffracted onto a detector where the spacing of the atoms within the crystal determine the diffraction pattern which shows up on the photo film detector and shows the structure of the molecule
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How many H bonds form between bases?
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Two Hydrogen bonds between A and T and three hydrogen bond between G and C
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What is the backbone of DNA? At what end are the phosphates hanging?
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the backbone is made of deoxyribose sugars linked by phosphates with an additional phosphate hanging off on the 5 prime ends, its 2 nm across and 3.4 nm for one twist
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Draw the sugar phosphate backbone: and show what changes if it was RNA
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figure 2, RNA has a OH where the inside H is on the sugar and it replaces T with U
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