1 / 12

Understanding DNA Structure and the Role of Restriction Enzymes

This overview explores the basic structure of DNA, highlighting its composition from nucleotides, including pentose sugar, phosphate, and nitrogen bases (adenine, guanine, thymine, and cytosine). DNA's double helix formation, according to Rosalind Franklin's findings, operates on Chargaff’s Rule for base pairing. We delve into the mechanisms of restriction enzymes, their bacterial origins, and how they cut DNA at specific sequences, producing blunt or sticky ends. Additionally, the process of gel electrophoresis for separating DNA fragments by size is discussed, along with its importance in genetic analysis.

khan
Download Presentation

Understanding DNA Structure and the Role of Restriction Enzymes

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 and Restriction Enzymes

  2. Basic Structure of DNA • Built of nucleotides: • Pentose sugar • Phosphate • Nitrogen base • Purines – adenine, guanine • Pyrmidines – thymine, cytosine • N base attached to 1’ C of sugar

  3. Struct., cont. • 3’ C of 1 sugar bonds to 5’ phosphate to form phosphodiester bond

  4. Complementary Strands • DNA arranged in double helix (Rosalind Franklin’s work) • Chargaff’s Rule: A—T and G—C (purine to pyrimidine) • Antiparallel – run 5’3’ on 1 strand and 3’5’ on other • 2 strands are complementary; i.e. • 3’—AGTAC—5’ • 5’—TCATG—3’

  5. Properties of DNA • Negative charge • PO4- • Together, negative charge and polar sugar = soluble • Genes & non-coding sections • DNA is universal

  6. How can we manipulate DNA?

  7. Restriction Enzymes • Isolated from bacteria • Used as immune mechanism to protect from phages • Named after bacteria they are isolated from • Recognize specific sequences of DNA • Palindromes • Ex. EcoRI recognizes GAATTC

  8. “Cut” DNA in a specific pattern at the recognition site • May produce: • Blunt ends • Sticky ends

  9. Number & placement of recognition sites determine # and size of fragments • RFLPs • http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter16/animations.html#

  10. Gel Electrophoresis • Separates DNA molecules based on size • Cut DNA using restriction enzyme(s) • Load DNA into gel • Run electrical current through buffer/gel • Stain DNA & compare unknowns to fragments of known sizes

  11. http://learn.genetics.utah.edu/content/labs/gel/

More Related