4. Sugar
• Deoxyribose in DNA (Ribose in RNA)
• http://www.mun.ca/biology/scarr/Deoxyribose_vs_Ribose.gif
5.
6. Nucleotide
• Condensation between the phosphate
and sugar (at C5) and between the
sugar (at C1) and base
• http://distancelearning.ksi.edu/demo/bio378/DNA_files/image002.gif
7. Dinucleotide
• Two nucelotides join by condensation
• http://pages.towson.edu/jdrawn/Chapter_1_Intro_to_Bioinfo_files/image005.jpg
• Condensation gives phosphodiester
bridge
8. Polynucleotide
• Up to 5 x 106 nucleotides long
• http://seqcore.brcf.med.umich.edu/doc/educ/dnapr/oligo.gif
• 5’ end
• 3’ end
9. DNA double helix
• The bases of the DNA nucleic acid
form H bonds to bases of a second
molecule of DNA
10. • A bonds to T with two hydrogen bonds
• G bonds to C with three hydrogen
bonds.
• http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/B/BasePairing.gif
11. • A is the ~same amount as T
• G is the ~same amount as C
• Amount of purines equals the
amount of pyrimidines
• A always bonds to T
• G always bonds to C
• Known as Chargaff’s Rule
13. • The two nucleic acids wind into a double helix,
with H bonds between polar groups of sugars
keeping the shape of the helix.
• (diagram from Bioligical Sciences, green, Stout & Taylor)
14. • The two strands are ANTIPARALLEL
• i.e. they are parallel, but run in
opposite directions.
16. Arrangement of DNA in chromosomes
http://www.biology.emory.edu/research/Lucchesi/multimedia/images/insert2.jpg
17. Histones in nucleosome
• DNA is wrapped around a group of 8
histone proteins and held together
by another histone molecule
• http://employees.csbsju.edu/hjakubowski/classes/ch331/dna/nucleosome.gif
19. DNA from a single skin cell, if
straightened out, would be about six feet
long but invisible. Half a gram of DNA,
uncoiled, would stretch to the sun.
Again, you couldn't see it.
