Nitrogen is essential to life a. it is needed for building the proteins needed for cells. b. it is the molecule around which all the molecules of life are built. c. it is needed for making carbohydrates and lipids. d. it is the most common element.

You have a solution that contains phospholipid vesicles in a test tube. these vesicles have phospholipid bilayers, but do not contain any membrane transporters. you add a number of different molecules to the solution, and wait a period of time for them to equilibrate. if you could measure the concentration of each molecule, for which of the following would you expect to measure equal concentrations inside and outside of the vesicles? assume for this question that the overall osmolarity inside and outside the vesicles is the same (that is, there is no appreciable diffusion of water across the membrane). (select two answers) an amino acid with a hydrophobic side-chain a small non-polar molecule a negatively charged ion a small polar molecule a small lipid hormone

What are the doorways into and out of cells, attached to the membrane, and built in the rough er.

What advantages does a pedigree have over a written passage?