Charlie was a 26-year-old drummer from San Francisco. He was a high school music teacher who had just returned from participating in a teacher exchange program in Mali. A week after his return, he developed a reaction to what he thought was an insect bite on this left hand. After a few days, the site became swollen and blistered. Finally, the lesion turned into a dark black ulceration, and it was at this point that Charlie sought out medical attention.

German cockroaches, bulging eyes, bu, are recessive to normal eyes, bu , and curved wings, cv, are recessive to straight wings, cv . both traits are encoded by autosomal genes that are linked. a cockroach has genotype bu bu cv cv, and the genes are in repulsion. which set of genes will be found in the most common gametes produced by this cockroach?

The kidney filters potentially toxic substances in the blood, and thus “clears” the blood of those substances. this clearance function is dependent upon and proportional to the diffusion gradient of the substance across filtering capillaries, i.e. if the concentration of the substance is doubled, twice as much will be cleared from each ml of blood that is filtered. suppose that the body produces a constant amount of a substance x per unit of time. the kidneys eliminate substance x at a rate directly proportional to the concentration of the substance and the volume of blood cleared each minute (c): elimination = c × [x], where [x] is the steady-state concentration of substance x. imagine an individual with an initial concentration of x equal to [x]0 who develops kidney disease. her baseline clearance c0 drops to one half of the original (½c0). what is the new steady state concentration of x? (for simplicity, assume that substance x is 100% filtered by the kidney).

To be or not to be that is da question