Adouble-stranded piece of alien nucleic acid has been isolated. each individual strand of the nucleic acid is 160 nucleotides long; for a total of 320 nucleotides in the isolated piece of nucleic acid. an initial analysis shows that of the 320 nucleotides, 95 contain the base uracil. how many nucleotides containing the base isoadenine (ia) would be found in the isolated piece of double-stranded nucleic acid?
(a) 0
(b) 95
(c) 190
(d) 225
(e) cannot be determined

The correct answer is option (B) "95".

Explanation:

Nucleic acids in double-stranded molecules follow certain rules for complementary bonding. In Earth's eukaryotic cells, adenine is attached to uracil and guanine is attached to cytosine. The proposed alien nucleic acids are not that different from Earth's nucleic acids, because isoAdenine (iA) could only be attached to uracil. Therefore, since the initial analysis shows that 95 of the 320 nucleic acids are uracil, 95 nucleotides containing the base isoAdenine (iA) would be found in the double-stranded molecule.

i thinking chemical change

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!