1 / 19

Gene Action

Gene Action. Protein Synthesis. Overview of Protein Synthesis … the short version. DNA contained in genes provides instructions for making protein Information from a specific section of DNA is first transcribed to produce a specific molecule of RNA

beau
Download Presentation

Gene Action

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Gene Action Protein Synthesis

  2. Overview of Protein Synthesis … the short version • DNA contained in genes provides instructions for making protein • Information from a specific section of DNA is first transcribed to produce a specific molecule of RNA • RNA attaches to a ribosome where the information is translated into a corresponding sequence of amino acids

  3. Protein Synthesis Vocab • Nucleotide – building block of nucleic acid: sugar, phosphate, base

  4. Protein Synthesis Vocab • Base Triplet – a sequence of three successive DNA nucleotides • Codon – a sequence of three successive mRNA nucleotides that correspond with a base triplet

  5. TRANSCRIPTION • DNA base triplets  mRNA codons • Just copying a message in the same language! • Nucleotide  nucleotide • Occurs in the Nucleus • Catalyzed by the enzyme RNA polymerase • Promoter – a special sequence of DNA nucleotides near the beginning of a gene that tell the RNA polymerase where to begin reading

  6. TRANSCRIPTION • Nucleotides pair complementarily: DNA RNA C - G G - C A - U T - A

  7. TRANSCRIPTION • Terminator – a specific sequence of DNA nucleotides that signals the end of the gene. • RNA polymerase detaches from the RNA molecule and the DNA strand. • The RNA leaves the nucleus through a nuclear pore

  8. Translation • The process in which mRNA associates with ribosomes and directs the synthesis of proteins by converting the sequence on nucleotides in RNA to a sequence of amino acids…HUH? • Changing Languages Now… • Nucleotide  Amino Acids

  9. Translation • http://staff.jccc.net/PDECELL/proteinsynthesis/translation/steps.html

  10. Translation • 1. An mRNA molecule binds to the small ribosomal subunit and a special tRNA molecules (the initiator) binds to the start codon (AUG), where translation begins

  11. Translation • 2. The large ribosomal subunit attaches to the small subunit, creating a functional ribosome • The initiator tRNA binds to the start codon • One end of the tRNA carries a specific amino acid, the other consists of a triplet of bases called an anticodon. • The anticodon pairs with the complementatry codon on mRNA

  12. Translation • 3. The anticodon of another tRNA with its amino acid attaches to the next section of mRNA • 4. A peptide bond is formed between the amino acids carried by the 2 tRNA’s

  13. Translation • 5. After the peptide bond forms, the tRNA detaches from the ribosome and the ribosome shifts the mRNA strand by 1 codon. A new tRNA with amino acid binds to the exposed codon. • Steps 3-5 repeat as the polypeptide lengthens

  14. Protein synthesis ends when the ribosome reaches a stop codon. • The new protein detaches, the tRNA detaches and the ribosome splits into its sub units

  15. How fast can this possibly happen? • In the body translation occurs at a rate of about 15 amino acids per second! • Before 1 ribosome finishes moving down the mRNA another can attach to that same strand allowing large amounts of protein to be built.

  16. tRNA

More Related