A. At one time the continent of Australia was connected to Asia. About 50 million years ago Australia became separated. It has many unusal animal not found elsewhere, such as the kangaroo and the koala bear. Using the concepts of geographic isolation the gene pool, explain why these animal developed. […]

Aspirin is a weak acid as shown below that is taken up into the bloodstream by diffusion through cells lining the stomach and the small intestine. Aspirin crosses the plasma membrane of a cell most effectively in its uncharged (protonated) form; in its charged (deprotonated) form it cannot cross the […]

You are asked to run an SDS-PAGE analysis of samples from an affinity chromatography experiment performed by your TA. A recombinant protein with a hexahistidine tag was captured in a nickel- agarose bead matrix and eluted off the column with 75mM imidazole. Your TA was hoping to make about 2 […]

M.L. is a 26-year-old homosexual man admitted to the hospital for progressive respiratory distress, fever, weakness, and chronic diarrhea. He tested HIV positive about 3 years ago, but his infection has remained asymptomatic until 2 months prior to admission. Pneumocystis jiroveci (carinii) pneumonia was suspected and confirmed by culture. Laboratory […]