This document provides information about nucleic acids. It discusses that nucleic acids function to store genetic information in the form of genes and blueprint for building proteins and new cells. It also describes that DNA and RNA are examples of nucleic acids, with DNA forming a double helix structure and RNA a single helix. The nucleotides that make up nucleic acids contain nitrogen bases, a pentose sugar, and phosphate groups.

1. 2006-2007AP Biology
Nucleic acids

2. 2006-2007AP Biology
Nucleic Acids
Information
storage

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

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A
A
A
A
T
C
G
C
G
T
G
C
T

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

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

7. AP Biology
Types of nucleotides
 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)
Purine = AG
Pure silver!

8. AP Biology
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?

9. AP Biology
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?

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

11. AP Biology
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?

12. AP Biology
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

13. AP Biology
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

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Watson and Crick … and others…
1953 | 1962

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Maurice Wilkins… and…
1953 | 1962

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Rosalind Franklin (1920-1958)

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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)

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

19. AP Biology
HELIXHELIXHELIXHELIX

20. 2006-2007AP Biology
Macromolecule
Review

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

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

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

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

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

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

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Building the polymer

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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!)

29. AP Biology
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?