1 / 21

DNA

DNA. What is DNA?. A code in the cell that contains the hereditary material The code is a chemical called deoxyribonucleic acid Every cell in your body contains DNA. DNA Structure. Rosalind Franklin discovered that DNA is two chains of molecules in a spiral form by using an X-ray

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. What is DNA? • A code in the cell that contains the hereditary material • The code is a chemical called deoxyribonucleic acid • Every cell in your body contains DNA

  3. DNA Structure • Rosalind Franklin discovered that DNA is two chains of molecules in a spiral form by using an X-ray • Similar to twisted ladder • James Watson & Francis Crick made a model of DNA molecule

  4. A DNA Model • Each side of the ladder is made of sugar-phosphate molecule • Called the “backbone” • Sugar = deoxyribose

  5. Rungs of the ladder are made up of nitrogenous bases • There are four types of bases • Adenine (A) • Guanine (G) • Cytosine (C) • Thymine (T)

  6. Base Pairing • Adenine always pairs with Thymine A-T • Cytosine always pairs with Guanine C-G

  7. Copying DNA • The two sides of DNA unwind and separate • Each side becomes a pattern for a new DNA strand

  8. Genes • DNA in your cells stores the instructions for making proteins • Each chromosome contains hundreds or thousands of genes

  9. Making Proteins • Genes are found in the nucleus, but proteins are made on ribosomes in the cytoplasm • The code for making proteins are carried from the nucleus by RNA or Ribonucleic Acid

  10. Ribonucleic Acid • RNA is different from DNA • RNA is not a spiral, but one single strand • RNA has the bases A, G, C, and U not T • U = Uracil • Sugar is ribose, not deoxyribose

  11. DNA VS. RNA

  12. Types of RNA • Messenger RNA (mRNA) • Transfer RNA (tRNA) • Ribosomal RNA (rRNA)

  13. Controlling Genes • Each cell only uses some of the thousands of genes to make proteins • Cells must be able to control genes by turning some genes on and others off

  14. Mutations • Permanent changes in the DNA sequence of a gene • These happen when the DNA is not copied correctly • They cause incorrect proteins to be made

  15. Causes of Mutations • X-rays • Sunlight • Some chemicals

  16. Results of Mutations • Some mutations are beneficial • They add variety to the species • Many mutations are harmful and can cause death • Cystic Fibrosis • Some mutations have no effect on the organism

More Related