1 / 11

DNA

DNA. Deoxyribonucleic Acid. Defined : Molecule that stores genetic information Nucleotides: Three repeating units of nucleic acids 1) Sugar 2) Phosphate Group 3) Nitrogen Base Millions of nucleotides per strand of DNA. How many Nucleotides?. Nucleotides.

zephr-hoffman
Download Presentation

DNA

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

  2. Deoxyribonucleic Acid • Defined: Molecule that stores genetic information • Nucleotides: Three repeating units of nucleic acids • 1) Sugar • 2) Phosphate Group • 3) Nitrogen Base • Millions of nucleotides per strand of DNA

  3. How many Nucleotides?

  4. Nucleotides • Sugar (Deoxyribose) connects with the phosphate group • 4 Different Bases: • Adenine (A) • Thymine (T) • Guanine (G) • Cytosine (C) • Rule: A always joins with T • Rule: C always joins with G • Human DNA: ~3 billion pairs C T A A T G T

  5. Double Helix • James Watson and Francis Crick identified DNA’s structure in 1953 • Double Helix: spiral shape of DNA • Left and right nucleotide strands are connected by a hydrogen bond

  6. DNA Replication • Defined: Process of copying DNA • During interphase (S-stage) • Step 1: DNA Helicase “unzips” the two DNA strands (breaks the H bonds) • Step 2: Free floating nucleotides (A, T, C, G) match up • Step 3: DNA Polymerase reconnects the two strands

  7. DNA Polymerase Glues the DNA T A A T G C G C Two Identical Strands of DNA! A T C G T A A T G C G C C G T A C G A T DNA Helicase Splits the DNA

  8. Video Clip

  9. Accuracy & Repair • Mutation: change in DNA sequence • Mutations can be corrected • Enzyme “proofreads” DNA and check/correct errors • Pre-repair: 1 in 10,000 nucleotides has an error • Post-repair: 1 in 1 billion nucleotides has an error

  10. Quick Review • DNA nucleotides form long chains • DNA nucleotides have 4 different bases (A, T, C, G) • DNA makes exact copies of itself

More Related