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5. 5 Translation Definition Translation Translation The actual process of protein synthesis where mRNA, made during transcription, leaves the nucleus, through nuclear pores located on the nuclear envelope, and attaches to a ribosome The actual process of protein synthesis where mRNA, made during transcription, leaves the nucleus, through nuclear pores located on the nuclear envelope, and attaches to a ribosome The production of a polypeptide (protein) whose amino acid sequence is derived from codon sequences The production of a polypeptide (protein) whose amino acid sequence is derived from codon sequences Put a star next to this--we will come back Put a star next to this--we will come back

6. 6 Playas of Translation RNA RNA Ribonucleic Acid Ribonucleic Acid A single stranded nucleic acid similar to DNA A single stranded nucleic acid similar to DNA Sugar is Ribose--not Deoxyribose that is found in DNA Sugar is Ribose--not Deoxyribose that is found in DNA Uracil replaces thymine as the nitrogen base Uracil replaces thymine as the nitrogen base mRNA mRNA Messenger RNA Messenger RNA An RNA molecule transcribed from the DNA of a gene An RNA molecule transcribed from the DNA of a gene Proteins are translated from mRNA by the help of RIBOSOMES Proteins are translated from mRNA by the help of RIBOSOMES Carries the GENETIC CODE, from DNA, used to create proteins Carries the GENETIC CODE, from DNA, used to create proteins

7. 7 Playas of Translation II tRNA tRNA Transfer RNA Transfer RNA Transports amino acid molecules to the ribosome Transports amino acid molecules to the ribosome Class of small RNA molecules that bear/carry specific amino acids to the ribsome during translation Class of small RNA molecules that bear/carry specific amino acids to the ribsome during translation What are the building blocks of proteins? What are the building blocks of proteins? Amino Acids Amino Acids The amino acids will be used to create a protein chain The amino acids will be used to create a protein chain Ribosome Ribosome Acts as the site of protein synthesis in the cell Acts as the site of protein synthesis in the cell How do we form the Rough Endoplasmic Reticulum? How do we form the Rough Endoplasmic Reticulum? When ribosomes bind to mRNA When ribosomes bind to mRNA Composed of Large subunits and small subunits Composed of Large subunits and small subunits Difference depends on type of rRNA Difference depends on type of rRNA Has three sites (EPA) Has three sites (EPA)

8. 8 rRNA rRNA Large Subunits Large Subunits Contain 30S Contain 30S Small Subunits Small Subunits Contain 15S Contain 15S Please remember that the size of the ribosome is determined by the amount of rRNA subunits Please remember that the size of the ribosome is determined by the amount of rRNA subunits

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11. 11 Playas of Translation III rRNA rRNA Ribosomal RNA Ribosomal RNA RNA that makes up the ribosomes RNA that makes up the ribosomes

12. 12 Playas of Translation IV Cracking the Genetic Code Codon Codon A group of three neucleotides that provide the information necessary to code for a single, specific amino acid A group of three neucleotides that provide the information necessary to code for a single, specific amino acid AUG AUG UAG UAG A section of RNA (three nucleotide pairs in length) that encodes a single amino acid A section of RNA (three nucleotide pairs in length) that encodes a single amino acid Found on mRNA Found on mRNA Anticodon Anticodon A nucleotide triplet, found on tRNA, that aligns with a particular codon in the mRNA A nucleotide triplet, found on tRNA, that aligns with a particular codon in the mRNA

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16. 16 Translation Step A Initiation All Biology Levels Ribosome binds to the mRNA Ribosome binds to the mRNA Small subunit binds to mRNA Small subunit binds to mRNA Initiator tRNA binds at start codon Initiator tRNA binds at start codon Start codon = AUG Start codon = AUG tRNA carries anti-codon UAC tRNA carries anti-codon UAC Initiator tRNA carries amino acid MET Initiator tRNA carries amino acid MET Ribosome binds to mRNA Ribosome binds to mRNA Large subunit binds to mRNA Large subunit binds to mRNA Initiator tRNA will be located at the P site of large subunit Initiator tRNA will be located at the P site of large subunit

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18. 18 Steps A - E Biology I & Biology I Honors  A. Initiation  B. Peptide Bond Formation  C. Elongation  D. Translocation  E. Termination  Stop Codons are recognized  All playas are released  Where do the proteins go after they are finished made?

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21. 21 Step B Peptide Bond Formation Biology I Honors & AP Biology Ribosome (rRNA) catalyzes the formation of a peptide bond between the new amino acid and the carboxyl end of the growing polypeptide Ribosome (rRNA) catalyzes the formation of a peptide bond between the new amino acid and the carboxyl end of the growing polypeptide

22. 22 Step C Elongation Elongation Occurs when the incoming amino acid binds to the polypeptide chain through the formation of a peptide bond. Occurs when the incoming amino acid binds to the polypeptide chain through the formation of a peptide bond.

23. 23 Step D Translocation Biology I Honors & AP Biology The ribosomes move allowing the tRNA’s to switch sites The ribosomes move allowing the tRNA’s to switch sites tRNA in the A (addition) site is translocated to the P (polypeptide) site tRNA in the A (addition) site is translocated to the P (polypeptide) site tRNA in the E (exit site) leaves the ribsome tRNA in the E (exit site) leaves the ribsome mRNA shifts position mRNA shifts position New tRNA with anticodon enters the A site New tRNA with anticodon enters the A site

24. 24 Step E Termination Biology I Honors & AP Biology Release factor (a protein) binds at stop codon Release factor (a protein) binds at stop codon Polypeptide chain released from tRNA Polypeptide chain released from tRNA tRNA released from P site tRNA released from P site Ribosomes released from mRNA Ribosomes released from mRNA

25. 25 Gene Mutations Discussed previously Discussed previously When the base sequence of a molecule of DNA is altered, the amino acid sequence of the polypeptide for which it codes will likewise be altered. When the base sequence of a molecule of DNA is altered, the amino acid sequence of the polypeptide for which it codes will likewise be altered. This affects the operation of enzymes This affects the operation of enzymes Remember enzymes are created from proteins Remember enzymes are created from proteins

26. 26 Mutations Continued DNA mutations DNA mutations Frame Shifts Frame Shifts Addition of Nucleotides Addition of Nucleotides Deletion of Nucleotides Deletion of Nucleotides Can result in genetic disorders previously discussed Can result in genetic disorders previously discussed Huntington Disease Huntington Disease This is how we get the dominant allele disorder This is how we get the dominant allele disorder Cystic Fibrosis Cystic Fibrosis Autosomal recessive disorder Autosomal recessive disorder Excess excretion of lung mucous Excess excretion of lung mucous Hemophilia Hemophilia X-linked recessive disorder X-linked recessive disorder Inability to clot blood Inability to clot blood

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28. 28 Types of Mutations Point Mutation Point Mutation Change a single nucleotide of a gene. Change a single nucleotide of a gene. Frameshift Mutation Frameshift Mutation Mutation that occurswhen the number of nucleotides inserted or deleted is not a multiple of three, resulting in the improper grouping of the following nucleotides into codons Mutation that occurswhen the number of nucleotides inserted or deleted is not a multiple of three, resulting in the improper grouping of the following nucleotides into codons Missense Mutation Missense Mutation The most common type of mutation where the new codon still codes for AN amino acid (not necessarily the same amino acid) The most common type of mutation where the new codon still codes for AN amino acid (not necessarily the same amino acid) Nonsense Mutation Nonsense Mutation A mutation that changes an amino acid codon to an amino acid codon that is a stop codon--usually resulting in a shorter, and non-functional form, of a protein A mutation that changes an amino acid codon to an amino acid codon that is a stop codon--usually resulting in a shorter, and non-functional form, of a protein

29. 29 Mutations Continued Substitution of Bases Substitution of Bases U for T in DNA U for T in DNA UV light rays UV light rays UV rays, from sunlight, enters the skin cells UV rays, from sunlight, enters the skin cells The proliferation genes, located on chromosomes inside the skin cells, are mutated The proliferation genes, located on chromosomes inside the skin cells, are mutated Thymine changes in Uracil Thymine changes in Uracil That results in the proliferation genes being constantly turned on That results in the proliferation genes being constantly turned on

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31. 31 Translation Step by Step IPETT Initiation Initiation Small subunit (ribosome) binds to the mRNA Small subunit (ribosome) binds to the mRNA Initiator tRNA binds at the start codon (AUG) Initiator tRNA binds at the start codon (AUG) Large subunit (ribosome) binds on the mRNA Large subunit (ribosome) binds on the mRNA tRNA moves to the P site of the large subunit tRNA moves to the P site of the large subunit Peptide bond formation Peptide bond formation Elongation Elongation Translocation Translocation Termination (stop codons) Termination (stop codons)