Biology

1.Why might a biologist be interested in comparing the amino acid sequence of proteins between two different species?  What differences might she find when comparing species that are distantly related or closely related?  Explain.
2.Trans-fatty acids are a type of unsaturated fat.  Most trans-fats consumed today are industrially created as a side effect of partial hydrogenation of plant oils (Crisco).  In trans-fat molecules, the hydrogens on the doubly bonded carbon atoms (characteristic of all unsaturated fats) are straighter, rather than kinked, in shape.  This straightening produces an unnatural molecule.  Why do you think trans-fats are considered unhealthy as compared to other unsaturated fats?  Can you explain your answer chemically?
3.Most adult humans lose the ability to digest dairy products, a condition known as lactose-intolerance because of an inactivity of the lactase enzyme for digestion. However, there is a high degree of lactose tolerant people who are from northern European descent.  How can you explain lactose tolerance from a chemical perspective and why would there be a greater frequency from northern Europe?
4.Epulos, a bacterium growing in the gut of tropical surgeon fish can reach the size of 500 micrometers.  How does this compare to other bacteria and what problems does this present the epulos?  What are some ways that a cell this size could alter its structure to survive?