Answer:
The correct answer is
18
Groups of the periodic table: The s-, p-, and d-block elements of the periodic table are arranged into 18 numbered columns, or groups.
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Answer:
These molecules are referred to in biology as the molecules of life. ... Without any of these four molecules, a cell and organism would not be able to live. All of the ... Many organisms have what is known as a cell wall that surrounds their cell. ... There are two types of nucleic acids that are essential to all lif
Explanation:
Mitosis results in two cells that are duplicates of the original cell. This kind of cell division occurs throughout the body, except in the reproductive organs. This is how most of the cells that make up the body are made and replaced.<span>Meiosis results in cells with half the number of chromosomes, 23 instead of the normal 46. These are the eggs and sperm. </span>
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.