As discussed in Chapter 3, DNA replication is a semiconservative process in which each parental strand serves as a template for the synthesis of a new complementary daughter strand. The central enzyme involved is DNA polymerase, which catalyzes the joining of deoxyribonucleoside 5′-triphosphates (dNTPs) to form the growing DNA chain. However, DNA replication is much more complex than a single enzymatic reaction. Other proteins are involved, and proofreading mechanisms are required to ensure that the accuracy of replication is compatible with the low frequency of errors that is needed for cell reproduction. Additional proteins and specific DNA sequences are also needed both to initiate replication and to copy the ends of eukaryotic chromosomes.
B. Inside prokaryotic cells
Answer:
The Miller and Urey experiment is a well-known classic experiment in which hypothetical conditions of the early Earth's evolution were simulated to test the possibility of chemical evolution. In fact, this was an experimental test of the hypothesis previously expressed by Alexander Oparin and John Haldane that the conditions that existed on primitive Earth promoted chemical reactions that could lead to the synthesis of organic molecules from inorganic ones. It was held in 1953 by Stanley Miller and Harold Urey. The apparatus designed for the experiment included a mixture of gases corresponding to the notion of the composition of the atmosphere of the early Earth in the 1950s, and electric discharges passing through it (simulating lightning strikes on the ground). The Miller and Urey experiment is considered one of the most important experiments in the study of the origin of life on Earth.
The earth rotates around its axis as it revolves around the sun. it takes the earth one year to complete a revolution.
