Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Acn dna notes


Published on


Published in: Health & Medicine, Technology
  • Be the first to comment

Acn dna notes

  1. 1. DNA (Deoxyribonucleic Acid)
  2. 2. A HISTORY OF DNA • Discovery of the DNA double helix A. Frederick Griffith – Discovers that a factor in diseased bacteria can transform harmless bacteria into deadly bacteria (1928) B. Rosalind Franklin - X-ray photo of DNA. (1952) C. Watson and Crick - described the DNA molecule from Franklin’s X-ray. (1953)
  3. 3. Watson & Crick proposed… •DNA had specific pairing between the nitrogen bases: ADENINE – THYMINE CYTOSINE - GUANINE •DNA was made of 2 long stands of nucleotides arranged in a specific way called the “Complementary Rule”
  4. 4. DNA Double Helix “Rungs of ladder” Nitrogenous Base (A,T,G or C) “Legs of ladder” Phosphate & Sugar Backbone
  5. 5. Genetic material of cells… • GENES – units of genetic material that CODES FOR A SPECIFIC TRAIT • Called NUCLEIC ACIDS • DNA is made up of repeating molecules called NUCLEOTIDES
  6. 6. DNA Nucleotide Phosphate Group O O=P-O O 5 CH2 O N C 1 C4 Sugar (deoxyribose) C3 C2 Nitrogenous base (A, G, C, or T)
  7. 7. DNA Double Helix 5 O 3 3 P 5 O O C G 1 P 5 3 2 4 4 2 3 P 1 T 5 A P 3 O O P 5 O 3 5 P
  8. 8. Nitrogenous Bases • PURINES 1. Adenine (A) 2. Guanine (G) A or G • PYRIMIDINES 3. Thymine (T) 4. Cytosine (C) T or C
  9. 9. Chargaff’s Rule • Adenine must pair with Thymine • Guanine must pair with Cytosine • Their amounts in a given DNA molecule will be about the same. same T A G C
  10. 10. BASE-PAIRINGS H-bonds G C T A
  11. 11. DNA is wrapped tightly around histones and coiled tightly to form chromosomes
  12. 12. Functions Genetic Diversity… • Different arrangements of NUCLEOTIDES in a nucleic acid (DNA) provides the key to DIVERSITY among living organisms.
  13. 13. The Code of Life… • The “code” of the chromosome is the SPECIFIC ORDER that bases occur. A T C G T A T G C G G…
  14. 14. DNA Replication • DNA must be copied • The DNA molecule produces 2 IDENTICAL new complementary strands following the rules of base pairing: A-T, G-C •Each strand of the original DNA serves as a template for the new strand
  15. 15. DNA Replication • Semi-conservative Model: 1. Watson and Crick showed: the two strands of the parental molecule separate, and each functions as a template for synthesis of a new complementary strand. . Parental DNA DNA Template New DNA
  16. 16. (1961) Watson & Crick proposed… • …DNA controlled cell function by serving as a template for PROTEIN structure. • 3 Nucleotides = a triplet or CODON (which code for a specific AMINO ACID) • AMINO ACIDS are the building blocks of proteins.
  17. 17. DNA Transcription • DNA can “unzip” itself and RNA nucleotides match up to the DNA strand. • Both DNA & RNA are formed from NUCLEOTIDES and are called NUCLEIC acids.
  18. 18. DNA Translation • The cell uses information from “messenger” RNA to produce proteins
  19. 19. AMAZING DNA FACTS… • DNA from a single human cell extends in a single thread for almost 2 meters long!!! • It contains information equal to some 600,000 printed pages of 500 words each!!! (a library of about 1,000 books)
  20. 20. RNA
  21. 21. Subdivisions • mRNA – messenger RNA • rRNA - ribosomal RNA • tRNA – transfer RNA
  22. 22. Thank you