1 / 12

Structure of DNA & Point Mutations

Structure of DNA & Point Mutations. Text ref 6.1 and 6.2. The Chemical Composition of DNA. Three main components: Pentose sugar (5 carbon ring) Phosphate group with negative charge Nitrogenous base. Three components together = nucleotide

milo
Download Presentation

Structure of DNA & Point Mutations

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. Structure of DNA & Point Mutations Text ref 6.1 and 6.2

  2. The Chemical Composition of DNA • Three main components: • Pentose sugar (5 carbon ring) • Phosphate group with negative charge • Nitrogenous base

  3. Three components together = nucleotide • DNA is made of MANY nucleotides in repeating units!

  4. 4 types of nitrogenous bases: T C A G

  5. DNA structure: • Amount of A = T • Amount of G = C • DNA has a phosphate-sugar “backbone”, and bases that “pair up” in the middle of the molecule. • A always pairs with T • G always pairs with C

  6. DNA is always double stranded and in a helix.

  7. Strands of DNA are always complementary • This means they “match up” • Ribosomes read DNA in groups of three nucleotides = instructions to build proteins!

  8. Point Mutations • Replicating cells do not copy genetic info in DNA accurately. • Three major types of point mutations: • Base-pair substitutions • Insertions • Deletions

  9. Base-Pair Substitutions: • One nitrogenous base is accidently replaced with another base.

  10. Insertions: • One or more nitrogenous base(s) is inserted during the copying process.

  11. Deletions: • One or more nitrogenous base(s) is deleted during the copying process.

  12. Homework • Page 233 #2, 4 • Page 239 #2, 3

More Related