Which statement about electrons and atomic orbitals is not true? 1. atom’s lowest energy level has only one orbital. 2.an electron cloud represents all the orbitals in an atom. 3.an electron has the same amount of energy in all orbitals. 4. an orbital can contain a maximum of two electrons.

Pepsin is an enzyme in the stomach that breaks polypeptides into amino acids. pepsin functions best at a ph of around 1.5. what would be the most likely result if the ph of the stomach were increased to 5

Considering the yellow and green pea color phenotypes studied by gregor mendel: a. what is the biochemical function of the protein that is specified by the gene responsible for the pea color phenotype? (1 point) b. a null allele of a gene is an allele that does not specify (or encode) any of the biochemical function that the gene normally provides (in other words, either no protein at all or only non-functional protein is produced from it). of the two alleles, y and y, which is more likely to be a null allele? (1 point) c. in terms of the underlying biochemistry, why is the y allele dominant to the y allele? (2 points) d. why are peas that are yy homozygotes green? (1 point) e. the amount of protein produced from a gene is roughly proportional to the number of functional copies of the gene carried by a cell or individual. what do the phenotypes of yy homozygotes, yy heterozygotes, and yy homozygotes tell us about the amount of sgr enzyme needed to produce a yellow color? explain your reasoning. (2 points)

Match the examples to the correct level of organization. 1. system level roses, snakes, puppies 2. organism level roots, stamens, leaves 3. tissue level bone, cartilage, blood 4. organ level heart, veins, arteries