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Chapter 13 Notes RNA and Protein Synthesis 13-1 RNA and Protein Synthesis RNA, like DNA, consists of long chains of nucleotides. Three differences between DNA and RNA - the sugar is ribose - single stranded - contains uracil (U) instead of thymine 13-1 RNA and Protein Synthesis Genes are coded DNA instructions that control the production of proteins. - each gene controls the production of a specific protein - DNA (gene) specific RNA sequence specific amino acid sequence 13-1 RNA and Protein Synthesis 13-1 RNA and Protein Synthesis There are three types of RNA: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA) mRNA: carries copies of instructions from DNA to the rest of the cell rRNA: along with proteins, makes ribosomes 13-1 RNA and Protein Synthesis 13-1 RNA and Protein Synthesis Ribosome Ribosomal RNA 13-1 RNA and Protein Synthesis Amino acid Transfer RNA 13-1 RNA and Protein Synthesis tRNA: transfers the message to the amino acid sequence Transcription: the copying of the DNA into a complementary strand of RNA - uses the enzyme RNA polymerase 13-2 RNA and Protein Synthesis During transcription, RNA polymerase binds to DNA and separates the DNA strands. RNA polymerase then uses one strand of DNA as a template from which nucleotides are assembled into a strand of RNA. The enzyme binds to the region DNA known as the promoter region. 13-2 RNA and Protein Synthesis Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only) RNA polymerase DNA RNA 13-2 RNA and Protein Synthesis RNA Editing Before it leaves the nucleus, RNA is edited. Splicing occurs by removing introns and fusing exons together. 13-2 RNA and Protein Synthesis Exon Intron DNA Pre-mRNA mRNA Cap Tail 13-3 RNA and Protein Synthesis The Genetic Code The genetic code is read in three letter segments called codons. There are 64 different codon possibilities -there are only 20 different amino acids that they code for -AUG is the start codon - there are 3 stop codons 13-3 RNA and Protein Synthesis 13-3 RNA and Protein Synthesis 12-3 RNA and Protein Synthesis Translation: the decoding of mRNA into an amino acid sequence During translation, the cell uses information from messenger RNA to produce proteins - anticodon: the three letter sequence on tRNA that binds with mRNA Protein synthesis animation 12-3 RNA and Protein Synthesis Nucleus mRNA 13-3 RNA and Protein Synthesis Phenylalanine Methionine Ribosome mRNA Start codon tRNA Lysine 13-3 RNA and Protein Synthesis Lysine tRNA Translation direction mRNA Ribosome 13-3 RNA and Protein Synthesis Polypeptide Ribosome tRNA mRNA Section Quiz The role of a master plan in a building is similar to the role of which molecule? messenger RNA DNA transfer RNA ribosomal RNA Section Quiz A base that is present in RNA but NOT in DNA is thymine. uracil. cytosine. adenine. Section Quiz The nucleic acid responsible for bringing individual amino acids to the ribosome is transfer RNA. DNA. messenger RNA. ribosomal RNA. Section Quiz A region of a DNA molecule that indicates to an enzyme where to bind to make RNA is the intron. exon. promoter. codon.