Imagine that you are studying a newly discovered bacterium from a hot springs in yellowstone national park. when you examine the nucleotide composition of this organism, you find that 10% of the nucleotides in its dna are adenine (a). what percentage of nucleotides are guanine?

40%

Explanation:

In order to make this calculation it is necessary to take into account the concept of base complementarity where it is known that the 2 strands of DNA bind together by base complementarity in which adenine binds to thymine and guanine to cytosine, this reason if they tell us that 10% is adenine the other 10% is thymine, so the rest will be guanine and cytosine (80%), so the percentage of guanine will be 40%.

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!