Reviewing Ideas and Using Concepts: P.258-259
1. Describe the function of tRNA, mRNA, and rRNA.
The function of tRNA is to delivers amino acid to ribosomes during translation in the order specified by the mRNA. The function of mRNA is to specify which amino acids must be placed during protein synthesis or translation. The function of rRNA is just to become part of the ribosomes. 2. In what situation does RNA play a role similar to enzymes? RNA is like an enzyme when it is a catalyst and helps assist in the reduction of the activation energy which relates to tRNA when it attaches its amino acid to the rightful place. This helps construe a faster translation. 3. Are all genes expressed at all times? Explain your answer. In order to have specialized cells that have different functions and structure, genes cannot be expressed at all times. Otherwise, we’d have cells with the same function. 4. What are the major steps in processing primary RNA transcripts into mRNA, tRNA, and rRNA? Transcription is the process that processes primary RNA transcripts into mRNA, tRNA, and rRNA. Gene expression begins with RNA synthesis. The transcription enzyme RNA polymerase joins RNA nucleotides according to the base sequence in DNA. Prokaryotes have one type of RNA polymerase. Transcription has four major processes Template recognition, Initiation, Elongation, and Termination. First RNA polymerase binds to duplex DNA. Then, DNA is unwound at promoter and then chain 2-9 bases are synthesized and released. Next, RNA polymerase moves, RNA is synthesized by base pairing with one strand of DNA and once RNA polymerase reaches end of gene it is released at the terminator and DNA duplex reforms. 5. Why does each codon have three nucleotides instead of two or one? It takes three nucleotides to construct an amino acid, because one or two nucleotides become considered non-coding or introns. 6. Describe the major steps of protein synthesis on the ribosome....
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