Agene on human chromosome 15 is expressed throughout the body. however, in the brain, only the maternal copy of the gene is expressed, whereas the paternal copy of the gene is silent and not transcribed. what accounts for this pattern of expression this gene displays in the brain?

Two true-breeding pea plants were crossed. one parent is round, terminal, violet, constricted, while the other expresses the respective contrasting phenotypes of wrinkled, axial, white, full. the four pairs of contrasting traits are controlled by four genes, each located on a separate chromosome. in the f1 only round, axial, violet, and full were expressed. in the f2, all possible combinations of these traits were expressed in ratios consistent with mendelian inheritance. (a) what conclusion about the inheritance of the traits can be drawn based on the f1 results? (b) in the f2 results, which phenotype appeared most frequently? what mathematical expression predicts the probability of occurrence of this phenotype? (c) which f2 phenotype is expected to occur least frequently? what mathematical expression predicts this probability? (d) in the f2 generation, how often is either of the p1 phenotypes likely to occur? express your answer as a fraction (example: 3/16).

Why do bacteria thrive even in hostile environments

Seen in some gram-positive bacilli, occurs when only the inner portion of a cell wall is deposited across the dividing cell. this new cross wall puts tension on the outer layer of the old cell wall. eventually, the outer wall breaks at its weakest point with a snapping movement that tears it most of the way around. the daughter cells can then remain hanging together almost side by side being held by a small remnant of the original outer wall. choose from the following statements the ones that correctly discuss reproduction using binary fission in a bacterial cell. select all that apply. view available hint(s) select all that apply. due to the stretching of the cytoplasmic membrane, both cells will contain a complete genome. each daughter cell will contain an equal number of organelles. the daughter cell will be a permanently smaller copy of the mother cell but will contain a complete genome. each daughter cell is an exact copy of the other, both genetically and morphologically