1 / 22

DNA Replication and Protein Synthesis

DNA Replication and Protein Synthesis. Watson and Crick…again. After describing the structure of DNA, they released a second paper Basically stated that the base pairing model indicated a method for replication

Download Presentation

DNA Replication and Protein Synthesis

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. DNA Replication and Protein Synthesis

  2. Watson and Crick…again • After describing the structure of DNA, they released a second paper • Basically stated that the base pairing model indicated a method for replication • Each strand would serve as a template for a new companion chain, called the complement

  3. As a result, each daughter strand has a strand from the original molecule • This is referred to as semi-conservative replication • So, from the parent strand, new bases are added to added according to the base pairing model • A strand of ATTCGACT would match up with TAAGCTGA

  4. Enzymes • A wide variety of enzymes are used during the replication process (recall anything ending in –ase is an enzyme) • The enzyme that opens the parent molecule by breaking the hydrogen bonds is helicase • It “unzips” the molecule • The other principle enzyme is DNA polymerase (actually three variations on it!) • It moves along the unwound strand, adding the appropriate bases

  5. Another version of the polymerase “checks” to ensure that no mistakes were made

  6. Protein Synthesis • Now that we know the structure of DNA, we can analyze how proteins are made • Broken down into two processes: transcription and translation • This is where RNA is used in our body • Structurally, RNA contains a ribose sugar • The 2’ carbon contains a hydroxyl group as opposed to a hydrogen

  7. Additionally, RNA tends to be single stranded, and contains a uracil in the place of thymine

  8. Different Types of RNA • In protein synthesis, three unique types of RNA are used: Messenger RNA (mRNA) • RNA copy of the DNA strand to be “read” during translation Transfer RNA (tRNA) • Carries individual amino acids to site of replication

  9. Ribosomal RNA (rRNA) • Attached to ribsome complex, site of protein synthesis rRNA tRNA

  10. Transcription • A complementary strand of mRNA is made, first by unzipping the DNA molecule • This time, by RNA polymerase • This only happens on specific regions of DNA known as promoter regions • That way, it isn’t just a random region • Similar regions cause the transcription process to stop

  11. RNA Splicing • Certain regions of DNA do not code for any proteins that we use, called introns • We mentioned these before as the “junk” regions • The introns must be spliced out, joining all the coding regions known as exons • Finally, a 5’ cap and poly A tail must be tacked on to the ends to finish the editing process

  12. Translation • The processed mRNA is now reading to be decoded • The “language” is spoken in three base “words”

  13. Translation begins when the mRNA binds to the rRNA on a ribosome • This moves along the sequence until an AUG codon is found • This is the start codon, and the methionine code, hence all protains begin with Met • tRNA then attaches and drops off the appropriate amino acid • It does this by have a matching anticodon • Sequential amino acids are linked by peptide bonds • So, it is called a polypeptide

  14. This process continues until a stop codon is found • Polypeptide and mRNA are release • Polypeptide goes through up to four stages of folding to become a mature protein

More Related