1. Nucleic acids
AP Biology 2006-2007

2. Nucleic Acids
Information
storage
AP Biology 2006-2007

3. Nucleic Acids
 Function:
 genetic material
 stores information
 genes
 blueprint for building proteins
 DNA → RNA → proteins
DNA  transfers information
 blueprint for new cells
 blueprint for next generation
AP Biology
proteins
proteins

4. T
G A
T C
C A
A G
G
A
AP Biology T
C

5. Nucleic Acids
 Examples:
 RNA (ribonucleic acid)
 single helix
 DNA (deoxyribonucleic acid)
 double helix
 Structure:
 monomers = nucleotides
AP Biology
DNA RNA

6. Nucleotides
 3 parts
 nitrogen base (C-N ring) Nitrogen base
 pentose sugar (5C) I’m the
A,T,C,G or U
 ribose in RNA part!
 deoxyribose in DNA
 phosphate (PO4) group
Are nucleic acids
charged molecules?
AP Biology

7. Types of nucleotides Purine = AG
Pure silver!
 2 types of nucleotides
 different nitrogen bases
 purines
 double ring N base
 adenine (A)
 guanine (G)
 pyrimidines
 single ring N base
 cytosine (C)
 thymine (T)
 uracil (U)
AP Biology

8. Nucleic polymer
 Backbone
 sugar to PO4 bond
 phosphodiester bond
 new base added to sugar of
previous base
 polymer grows in one direction
 N bases hang off the
sugar-phosphate backbone
Dangling bases?
Why is this important?
AP Biology

9. Pairing of nucleotides
 Nucleotides bond between
DNA strands
 H bonds
 purine :: pyrimidine
 A :: T
 2 H bonds
 G :: C
 3 H bonds
Matching bases?
Why is this important?
AP Biology

10. DNA molecule
 Double helix
 H bonds between bases
join the 2 strands
 A :: T
 C :: G
H bonds?
Why is this important?
AP Biology

11. Copying DNA
 Replication
 2 strands of DNA helix are
complementary
 have one, can build other
 have one, can rebuild the
whole
Matching halves?
Why is this
a good system?
AP Biology

12. When does a cell copy DNA?
 When in the life of a cell does DNA have
to be copied?
 cell reproduction
 mitosis
 gamete production
 meiosis
AP Biology

13. DNA replication
“It has not escaped our notice that
the specific pairing we have
postulated immediately suggests a
possible copying mechanism for the
genetic material.”
James Watson
Francis Crick
1953
AP Biology

14. 1953 | 1962
Watson and Crick … and others…
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15. 1953 | 1962
Maurice Wilkins… and…
AP Biology

16. Rosalind Franklin (1920-1958)
AP Biology

17. Interesting note…
 Ratio of A-T::G-C
affects stability
of DNA molecule
 2 H bonds vs. 3 H bonds
 biotech procedures
 more G-C =
need higher T° to
separate strands
 high T° organisms
 many G-C
 parasites
 many A-T (don’t know why)
AP Biology

18. Another interesting note…
 ATP
Adenosine triphosphate
 modified nucleotide
 adenine (AMP) + Pi + Pi
+ +
AP Biology

19. HELIXHELIX
AP Biology

20. Macromolecule
Review
AP Biology 2006-2007

21. Carbohydrates
 Structure / monomer
 monosaccharide
 Function
 energy
 raw materials
 energy storage glycosidic bond
 structural compounds
 Examples
 glucose, starch, cellulose, glycogen
AP Biology

22. Lipids
 Structure / building block
 glycerol, fatty acid, cholesterol, H-C chains
 Function
 energy storage
 membranes
 hormones
 Examples ester bond (in a fat)
 fat, phospholipids, steroids
AP Biology

23. Proteins
 Structure / monomer
 amino acids
 levels of structure
 Function
 enzymes defense
 transport structure peptide bond
 signals receptors
 Examples
 digestive enzymes, membrane
channels, insulin hormone, actin
AP Biology

24. Nucleic acids
 Structure / monomer
 nucleotide
 Function
 information storage
& transfer
 Examples
 DNA, RNA
AP Biology phosphodiester bond

25. Let’s build
some DNA, baby!
AP Biology

26. Ghosts of Lectures Past
(storage)
AP Biology 2007-2008

27. Building the polymer
AP Biology

28. RNA & DNA
 RNA
 single nucleotide chain
 DNA
 double nucleotide chain
 N bases bond in pairs
across chains
 spiraled in a double helix
 double helix 1st proposed as structure of DNA in
1953 by James Watson & Francis Crick
(just celebrated 50th anniversary in 2003!)
AP Biology

29. Information polymer
 Function
 series of bases encodes information
 like the letters of a book
 stored information is passed
from parent to offspring
 need to copy accurately
 stored information = genes
 genetic information
Passing on information?
Why is this important?
AP Biology