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Protein Synthesis: Creating proteins from DNA

Protein Synthesis: Creating proteins from DNA. Review. DNA is located in the nucleus of eukaryotic cells. Found in the cytoplasm of prokaryotes DNA Replication the process of synthesizing a new strand of DNA; Semi conservative. What are the steps in DNA Replication?. DNA Double Stranded

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Protein Synthesis: Creating proteins from DNA

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  1. ProteinSynthesis:Creating proteins from DNA

  2. Review • DNA is located in the nucleus of eukaryotic cells. Found in the cytoplasm of prokaryotes • DNA Replicationthe process of synthesizing a new strand of DNA; Semi conservative

  3. What are the steps in DNA Replication?

  4. DNA Double Stranded In the nucleus only Adenine - Thymine Cytosine - Guanine Deoxyribose sugar RNA Single stranded In cytoplasm and nucleus Adenine – Uracil (thymine is replaced by uracil) Cytosine – Guanine Ribose sugar DNA vs. RNADNA is a blueprint to make RNA or Ribonucleic Acid.

  5. Types of RNA (Ribonucleic acid) • rRNA – ribosomal RNA, the principle component of ribosomes. Site where amino acids are joined together to form Proteins • mRNA – Messenger RNA, carries the DNA code from the nucleus to the ribosome. • tRNA – Transfer RNA, carries amino acids to ribosome

  6. DNA cannot leave nucleus, therefore genetic information must be copied into RNA The copies (RNA) are then sent into the cytoplasm to make proteins. These copies are single strands of RNA. Transcription occurs 5’ to 3’ direction Step 1:Transcription (DNA to RNA)

  7. Figure 12–14 Transcription Section 12-3 Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only) RNApolymerase DNA RNA

  8. Helicase: unwinds DNA helix RNA Polymerase: finds and matches free floating RNA nucleotides to DNA.These free nucleotides once put in order forms the RNA. When it reaches the stop sequence, polymerase detaches and RNA is free. 3. Ligase: seals the DNA Helix 4. The RNA strand, now called mRNA, leaves the DNA molecule and the nucleus. 5. Gyrase winds up the DNA strand. Steps in Transcription

  9. Transcribing rules DNA to mRNA A to U T to A C to G G to C

  10. LetsPractice DNA AAT CCG GCG TAT mRNA UUA GGC CGC ATA

  11. This molecule of mRNA then passes out of the nucleus and into the cytoplasm for the second stage

  12. Translation: RNA helps form proteins.

  13. The genetic code (Translation) • Every three nucleotides in mRNA specify a particular amino acid. • This nucleotide triplet is called a codon. • Codons determine amino acids; a chain or amino acids determine that type of protein being made.

  14. The genetic code is the correspondence between nucleotide triplets in DNA and the amino acids and proteins. • There are 64 possible codons but only twenty different amino acids. More than one codon may specify an amino acid. • “STOP” codons specify the end of an amino acid chain.

  15. Circular Codon Charts

  16. Rectangular Codon Chart

  17. Translation continued • During translation mRNA works with two other types of RNA to build proteins by joining amino acids. • Translation occurs on ribosomes that contain ribosomal RNA or rRNA. • An mRNA molecule passes between the two subunits of a ribosome. • Transfer RNA or tRNA , carries amino acids to the ribosome.

  18. The tRNA has an anticodon, which is a three nucleotide sequence, which are complementary to mRNAcodons. • Amino acids are added to the growing protein chain until the stop codon is reached.

  19. Figure 12–18 Translation Section 12-3

  20. Figure 12–18 Translation (continued) Section 12-3

  21. Translating rules mRNA to tRNA U to A A to U C to G G to C

  22. LetsPractice DNA AAT CCG GCG TAT mRNA UUA GGC CGC AUA tRNA AAU CCG GCG UAU

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