ribosomal proteins to make ribosomes, tRNA bings to an amino acid and holds itin place on ribosome until it is incorporated into a protein during translation Promoter – segment of DNA where transcription begins; this is where RNA polymerase attaches to the DNATerminator – transcription of the DNA strand ends at another special nucleotide sequence, which specifies the end of the gene oTranslation – RNA attaches to a ribosome, where the information in the RNA is translatedinto a corresponding sequence of amino acids to form a new protein molecule (cytoplasm) 1.An mRNA molecule binds to the small ribosomal subunits at the mRNA binding site. A special tRNA, called initiator tRNA, binds to the start codon (AUG) on mRNA, where translation begins. The tRNA anticodon (UAC)
attaches to the mRNA codon (AUG) by pairing between the complementarybases. 2.The large ribosomal subunit attaches to the small ribosomal sub-unit mRNAcomplex, creating a functional ribosome. The initiator tRNA, with its aminoacid (methionine) fits into the P site of the ribosome. 3.The anticodon of another tRNA with its attached amino acid pairs with the second mRNA codon at the A site of the ribosome. 4.A component of the large ribosomal subunit catalyzes the formation of a peptide bond between methionine and the amino acid carried by the tRNA at the A site. 5.Following the formation of the peptide bond, the resulting two-peptide protein becomes attached to the tRNA as the A site. 6.After peptide bond formation, the ribosome shifts the mRNA strand by one codon. The tRNA in the P site enters the E site and it subsequently release from the ribosome. The tRNA in the A side bearing the two-peptide protein shifts into the p site, allowing another tRNA with its amino acid to bind to a newly exposed codon at the A site. Steps 3 – 6; protein lengthens7.Protein synthesis ends when the ribosome reaches a stop codon at the A site,which causes the completed protein to detach from the final tRNA. In addition, tRNA vacates the P site and the ribosome splits into its large and small subunits.
Cell Division – the process by which cells reproduce themselves Germ Cell – gamete (sperm or oocyte) or any precursor cell destined to become a gamete Somatic cell – any cell of the body other than a germ cell Somatic Cell Division – undergoes a nuclear division mitosis Mitosis – cellular division Cytokinesis – cytoplasmic division Reproductive cell division – is the mechanism that produces gametes, the cells needed to form the next generation of sexually reproducing organisms. This process consists of a special two-step division called meiosis, in which the number of chromosomes in the nucleus, is reduced by half. Cell Cycle – is an orderly sequence of events in which a somatic cell duplicates its contents and divides in two.
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- Spring '17