Download AP Biology Deoxyribonucleic acid

Nucleic acids
AP Biology
2006-2007
Nucleic Acids
Information
storage
AP Biology
Nucleic Acids-C,H,O,N,P
 Function:

genetic material
 stores information
 genes
 blueprint for building proteins

DNA
DNA  RNA  proteins
 transfers information
 blueprint for new cells
 blueprint for next generation
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proteins
G
C
T
A
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A
C
G
T
A
C
G
T
A
Nucleic Acids
 Examples:

RNA (ribonucleic acid)
 single helix

DNA (deoxyribonucleic acid)
 double helix
 Structure:

AP Biology
monomers = nucleotides
DNA
RNA
Nucleotides
 3 parts
nitrogen base (C-N ring)
 pentose sugar (5C)

 ribose in RNA
 deoxyribose in DNA

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phosphate (PO4) group
Nitrogen base
I’m the
A,T,C,G or U
part!
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)
AP Biology
Purine = AG
Pure silver!
Nucleic Acids
 Nitrogeneous bases can be:
 Purines (Adenine and Guanine) ~ double-ring
 Pyrimidines (Cytosine, Thymine and Uracil)
~ single-ring
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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
Deoxyribonucleic acid (DNA)
Nitrogen base attached to sugar
at C-1
Phosphate attached to sugar
at C-5
Phosphate attached to next
nucleoside at C-1 by
phosphodiester linkage
Each strand has a 3’ and 5’ end
AP Biology
http://staff.um.edu.mt/acus1/3Molgen.htm
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
DNA molecule
 Double helix

H bonds between bases
join the 2 strands
 A :: T
 C :: G
H bonds?
Why is this important?
AP Biology
Deoxyribonucleic acid (DNA)
Complementary strands
H bonds ~ between paired bases
van der Waals ~ between stacked bases
AP Biology
http://staff.um.edu.mt/acus1/3Molgen.htm
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?
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Deoxyribonucleic acid (DNA)
 Strands run antiparallel
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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
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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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1953 | 1962
Watson and Crick … and others…
Proposed the
structure of DNA.
1962 – won the
Nobel Prize with
Wilkins.
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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
+
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+
Ribonucleic acid (RNA)
Ribose sugar
Nitrogeneous bases:
A, C, G, and U
SINGLE STRANDED
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http://www.biology.arizona.edu/biochemistry/problem_sets/large_molecules/06t.html
RNA
 RNA functions in protein synthesis.
 There are three types of RNA:
Messenger RNA (mRNA)
~ blueprint for construction of a protein.
Ribosomal RNA (rRNA)
~ construction site where the protein is made.
Transfer RNA (tRNA)
~ truck delivering the proper amino acid to the site
at the right time.
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Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
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DNA → RNA → protein
Information in Biology
•Biological systems process matter, energy, and
information.
•The information directs the construction of
proteins.
•This is known as the “Central Dogma” of
molecular biology.
•It will be the underpinning of most biological
advances during your lifetime.
AP Biology
Macromolecule
Review
AP Biology
Carbohydrates
 Structure / monomer

monosaccharide
 Function
energy
 raw materials
 energy storage
 structural compounds

glycosidic bond
 Examples

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glucose, starch, cellulose, glycogen
Lipids
 Structure / building block

glycerol, fatty acid, cholesterol, H-C chains
 Function
energy storage
 membranes
 hormones

 Examples

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ester bond (in a fat)
fat, phospholipids, steroids
Proteins
 Structure / monomer
amino acids
 levels of structure

 Function
enzymes
 transport
 signals

defense
 structure
 receptors

peptide bond
 Examples

AP Biology
digestive enzymes, membrane
channels, insulin hormone, actin
Nucleic acids
 Structure / monomer

nucleotide
 Function

information storage
& transfer
 Examples

AP Biology
DNA, RNA
phosphodiester bond
Ghosts of Lectures Past
(storage)
AP Biology
2007-2008
Building the polymer
AP Biology
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!)
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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