Dna structure notes

Introduction to DNA Structure

1. DNA Structure

2. DNA - D eoxyribo n ucleic A cid Found in nucleoid of prokaryotic cells Found in the nucleus of all eukaryotic cells In mitochondria ( mtDNA ) In chloroplasts ( ctDNA ) Different segments along the DNA are genes Genes - determine body function and physical characteristics Genes are located on chromosomes. Chromosomes are made of DNA & proteins

3. Simplified Nucleotide Model S P B Draw & Label

4. Nitrogenous Bases of DNA

5. Nitrogen Bases Adenine Guanine Thymine Cytosine Purines Pyrimidines

6. STRUCTURE OF DNA Double stranded helix ( twisted, curved) Right-handed twist

7. DNA - Double Helix Structure 1) Sides of the ladder are made up of sugar and phosphates 2) Nitrogen bases stick out from the sides of the ladder (rungs) 3) When the two sides (chains) of the ladder are connected, it’s a complete DNA molecule

8. DNA - Double Helix 4) Adenine bonds with Thymine* 5) Guanine bonds with Cytosine* 6) Hydrogen bonds connect the bases *see next slide

9. Edwin Chargaff – 1947 Studied DNA in various species Nitrogen bases are proportionate within a species Ratio of bases are various between species Adenine and Thymine were found in proportionate amounts Cytosine and Guanine were found in proportionate amounts Chargaff’s Rules

10. S P P P P P P S S S S S A T T C G A Draw DNA

11. Bases Side/backbone

12. Nucleotide

13. DNA Structure

14. DNA Structure

15. 3.4

16. 0.34

17. 1

18. Base pair

19. deoxyribose deoxyribose

20. phosphate

21. h ydrogen bonds

22. 5’ 5’

23. 3 ’ 3 ’