The nitrogen fixation is a very important process because it is the principal source of nitrogen in the marine environment for photosynthetic plants. Nitrogen is a growth limiting nutrient, that is very important for the growth of photosynthetic plants. During the process of nitrogen fixation, nitrogen is absorbed from the atmosphere and it is fixed by nitrogen fixing organisms.
<span>The nitrogen fixing performed by cyanobacteria and some archaea transforms nitrogen in the form of N2, which is very common, into the form NO3 and NH4, which are much less common. This is important because most ocean plants -- particularly the plankton that makes up the majority of oceanic plant life -- need nitrogen in order to transform sunlight into energy but cannot use it in the common N2 form. So the nitrogen fixation carried out by cyanobacteria and archaea transform nitrogen into a form in which it is usable by other ocean organisims.</span>
The enzyme Topoisomerase functions to prevent super-coiling of the DNA molecule during replication.
Explanation:
During replication, topoisomerases are required to relieve the positive supercoiling that arises from DNA unwiding mediated by Helicases.
A DNA topoisomerase is a nuclease that breaks a phosphodiester bond in a DNA strand.
All topoiomereases are classified as Topoisomerase I and Topoisomerase II depending on whether they cleave one or two strands respectively.
Topoisomerase I do not use ATP as a source of energy, the reaction is powered by energy stored in super-coiled DNA.
Topoisomerase II also do not require external energy but it utilizes ATP hydrolysis to drive conformation changes in the protein during reaction cycle.
A diploid cell is a cell that contains two complete sets of chromosomes. This is double the haploid chromosome number. Each pair of chromosomes in a diploid cell is considered to be a homologous chromosome set.
"Two long tails extend from the edge of the spiral pattern [of the Milky Way] and trail out beyond the galaxy, giving an indication of the Milky Way's direction of rotation."
Answer: mutations that natural selection can work on. 4.) How do scientists calibrate a molecular clock? ... they compare the number of positive mutations that have occurred in a particular species with the number of negative mutations that have occurred
