Answer:
Thymine in DNA occurs as the result of thymidylate synthase creating deoxythymidine monophosphate (dTMP), which then undergoes phosphorylation to deoxythymidine diphosphate (dTDP), then to Deoxythymidine triphosphate (dTTP), and incorporated into DNA by the DNA polymerase (DNA pol). Thymine in tRNA arises post-transcriptionally, by S-adenosylmethionine-dependent methylation of a uridine 5'-monophosphate (UMP) residue in RNA.
Explanation:
Thymidylate synthase is an enzyme involved in <em>de novo</em> DNA synthesis. This enzyme (thymidylate synthase) catalyzes the transfer of the one-carbon group from 5,10-methylene-tetrahydrofolate (5,10-CH2-THF) to deoxyuridine monophosphate (dUMP) and subsequent methylation to produce deoxythymidine monophosphate (dTMP), which is then phosphorylated to deoxythymidine triphosphate (dTTP) by kinases and incorporated into DNA. On the other hand, specific tRNA methylases catalyze the methylation of transference RNA (tRNA) by using S-adenosylmethionine as a methyl donor. Since tRNA methylation is a post-transcriptional modification, this chemical reaction is considered an epitranscriptomic modification on the RNA molecule.
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“The top consumer of a food chain will be the organism that receives the least amount of energy.”
Answer:
If a nation were to depend on foreign oil, if there were be an natural event to the country the nation is depending on that would cause a problem such as decreasement of oil or make it hard to export oil it would be hard to find an alternative efficiently. If there was to be a war or feud, or you eliminate an export to the country with the oil, they might stop sending oil.
Explanation:
Answer:
(1) photosynthesis, (2) cellular respiration
Explanation: