End Show Slide 1 of 39 Copyright Pearson Prentice Hall Biology

End Show Slide 2 of 39 Copyright Pearson Prentice Hall 12-3 RNA and Protein Synthesis 12–3 RNA and Protein Synthesis

End Show 12–3 RNA and Protein Synthesis Slide 3 of 39 Copyright Pearson Prentice Hall 12–3 RNA and Protein Synthesis Genes are coded DNA instructions that control the production of proteins. Genetic messages can be decoded by copying part of the nucleotide sequence from DNA into RNA. RNA contains coded information for making proteins.

End Show 12–3 RNA and Protein Synthesis Slide 4 of 39 Copyright Pearson Prentice Hall The Structure of RNA There are three main differences between RNA and DNA: The sugar in RNA is ribose instead of deoxyribose. RNA is generally single-stranded. RNA contains uracil in place of thymine.

End Show 12–3 RNA and Protein Synthesis Slide 5 of 39 Copyright Pearson Prentice Hall Types of RNA There are three main types of RNA: messenger RNA - mRNA ribosomal RNA - rRNA transfer RNA - tRNA

End Show 12–3 RNA and Protein Synthesis Slide 6 of 39 Copyright Pearson Prentice Hall Types of RNA Messenger RNA (mRNA) carries copies of instructions for assembling amino acids into proteins.

End Show 12–3 RNA and Protein Synthesis Slide 7 of 39 Copyright Pearson Prentice Hall Types of RNA Ribosomes are made up of proteins and ribosomal RNA (rRNA). Ribosome Ribosomal RNA

End Show 12–3 RNA and Protein Synthesis Slide 8 of 39 Copyright Pearson Prentice Hall Types of RNA During protein construction, transfer RNA (tRNA) transfers each amino acid to the ribosome. Amino acid Transfer RNA

End Show 12–3 RNA and Protein Synthesis Slide 9 of 39 Protein SynthesisDNAmolecule DNA strand (template) 3 TRANSCRIPTION Codon mRNA TRANSLATION Protein Amino acid 3 5 5

End Show 12–3 RNA and Protein Synthesis Slide 10 of 39 Copyright Pearson Prentice Hall Transcription DNA is copied in the form of RNA This first process is called transcription. The process begins at a section of DNA called a promoter.

End Show 12–3 RNA and Protein Synthesis Slide 11 of 39 Copyright Pearson Prentice Hall Transcription RNA RNA polymerase DNA

End Show 12–3 RNA and Protein Synthesis Slide 12 of 39 Copyright Pearson Prentice Hall RNA Editing Some DNA within a gene is not needed to produce a protein. These areas are called introns. The DNA sequences that code for proteins are called exons.

End Show 12–3 RNA and Protein Synthesis Slide 13 of 39 Copyright Pearson Prentice Hall RNA Editing The introns are cut out of RNA molecules. The exons are the spliced together to form mRNA. Exon Intron DNA Pre-mRNA mRNA Cap Tail

End Show 12–3 RNA and Protein Synthesis Slide 14 of 39 Copyright Pearson Prentice Hall The Genetic Code The genetic code is the “language” of mRNA instructions. The code is written using four “letters” (the bases: A, U, C, and G).

End Show 12–3 RNA and Protein Synthesis Slide 15 of 39 Copyright Pearson Prentice Hall The Genetic Code A codon consists of three consecutive nucleotides on mRNA that specify a particular amino acid.

End Show 12–3 RNA and Protein Synthesis Slide 16 of 39 Copyright Pearson Prentice Hall The Genetic Code

End Show 12–3 RNA and Protein Synthesis Slide 17 of 39 Nucleus mRNA Copyright Pearson Prentice Hall Translation Translation is the decoding of an mRNA message into a polypeptide chain (protein). Translation takes place on ribosomes. During translation, the cell uses information from messenger RNA to produce proteins.

End Show 12–3 RNA and Protein Synthesis Slide 18 of 39 Copyright Pearson Prentice Hall Translation Lysine tRNA Phenylalanine Methionine Ribosome mRNA Start codon The ribosome binds new tRNA molecules and amino acids as it moves along the mRNA.

End Show 12–3 RNA and Protein Synthesis Slide 19 of 39 Copyright Pearson Prentice Hall Translation Protein Synthesis tRNA Ribosome mRNA Lysine Translation direction

End Show 12–3 RNA and Protein Synthesis Slide 20 of 39 Copyright Pearson Prentice Hall Translation The process continues until the ribosome reaches a stop codon. Polypeptide Ribosome tRNA mRNA

End Show 12–3 RNA and Protein Synthesis Slide 21 of 39 Copyright Pearson Prentice Hall Genes and Proteins DNA mRNA Protein Codon mRNA Alanine Arginine Leucine Amino acids within a polypeptide Single strand of DNA

End Show - or - Continue to: Click to Launch: Slide 22 of 39 Copyright Pearson Prentice Hall 12–3

End Show Slide 23 of 39 Copyright Pearson Prentice Hall 12–3 The role of a master plan in a building is similar to the role of which molecule? a.messenger RNA b.DNA c.transfer RNA d.ribosomal RNA

End Show Slide 24 of 39 Copyright Pearson Prentice Hall 12–3 A base that is present in RNA but NOT in DNA is a.thymine. b.uracil. c.cytosine. d.adenine.

End Show Slide 25 of 39 Copyright Pearson Prentice Hall 12–3 The nucleic acid responsible for bringing individual amino acids to the ribosome is a.transfer RNA. b.DNA. c.messenger RNA. d.ribosomal RNA.

End Show Slide 26 of 39 Copyright Pearson Prentice Hall 12–3 A region of a DNA molecule that indicates to an enzyme where to bind to make RNA is the a.intron. b.exon. c.promoter. d.codon.

End Show Slide 27 of 39 A codon typically carries sufficient information to specify a(an) a.single base pair in RNA. b.single amino acid. c.entire protein. d.single base pair in DNA. Copyright Pearson Prentice Hall 12–3

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