LE 16-2 Living S cells (control) Living R cells (control) Heat-killed S cells (control) Mixture of heat-killed S cells and living R cells Mouse dies Living S cells are found in blood sample Mouse healthy Mouse dies RESULTS
LE 16-3 Bacterial cell Phage head Tail Tail fiber DNA 100 nm
Figure 10.1A Head Tail Tail fiber DNA
Phage Bacterium Batch 2: Radioactive DNA labeled in green DNA Radioactive protein Centrifuge Phage DNA Empty protein shell Pellet The radioactivity is in the liquid. Radioactive DNA Centrifuge Pellet The radioactivity is in the pellet Batch 1: Radioactive protein labeled in yellow Radioactive Sulfur used to label protein Radioactive Phosphorous used to label DNA
A A A A A A A C T T T T T T C C C C G G G G G C CG A T A DNA double helix T DNA nucleotide Covalent bond joining nucleotides A C T Two representations of a DNA polynucleotide G G G G C T Phosphate group Sugar (deoxyribose) DNA nucleotide Thymine (T) Nitrogenous base (can be A, G, C, or T) Sugar Nitrogenous base Phosphate group Sugar-phosphate backbone The nucleotides are joined to one another by a COVALENT BOND between sugar-phosphate backbone.
Sugar–phosphate backbone 5 end Nitrogenous bases Thymine (T) Adenine (A) Cytosine (C) DNA nucleotide Phosphate 3 end Guanine (G) Sugar (deoxyribose) The nucleotides are joined to one another by a COVALENT BOND between sugar- phosphate backbone.
LE 16-6 Franklins X-ray diffraction photograph of DNA Rosalind Franklin
5 end 3 end 5 end 3 end Space-filling modelPartial chemical structure Hydrogen bond Key features of DNA structure 0.34 nm 3.4 nm 1 nm Nucleotides in opposing strands are connected by HYDROGEN bonds Notice the two nucleotide strands run anti-parallel (opposite) of each other!