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Let’s Review!
• What is a macromolecule?
- A large ___________ molecule (made of carbon!)
• What are the four kinds of organic
molecules?
- Carbohydrates, lipids, proteins and _______________
• What are nucleic acids made of?
- Phosphate group, _____________nitrogenous base
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___________are the chemical link
between generations dating back to the
beginning of life on earth.
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• A nucleic acid is a
complex
macromolecule that
stores information in
cells in the form of a
________.
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• Nucleic acids are made of long chains
of _______________.
• ____________are made
components:
1. sugar
2. phosphate group
3. nitrogen base
of
three
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• Examples of nucleic acids are :
1. _____
2. RNA
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DNA = deoxyribonucleic acid
its components are:
1. deoxyribose (_____)
2. phosphate group
3. nitrogen base
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The Components and Structure of DNA
There are four
kinds of bases
in in DNA:
•
•
•
•
adenine
guanine
________
thymine
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• Rosalin Franklin, Maurice Wilkins,
• James ______ and Francis _____
proposed the structure of DNA:
Chargaff proposed
Adenine (A) – Thymine (T)
Guanine (G) – Cytosine (C)
A and G are purines
C and T are pyrimidines
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Watson & Crick
Discovered the structure of DNA
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• Watson and Crick
also said the paired
nitrogen bases
formed ______long
strands of
nucleotides that
compliment each
other.
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• Nitrogen Bases are connected
between sugars and phosphates
• They declared, “This structure is
a “__________________”.
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DNA Double Helix
The Components and Structure of DNA
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• DNA forms _________________, units
of genetic information which pass from
parent to offspring.
DNA is wound into
structures called
chromosomes
during cell
division
(prophase)
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What are chromosomes???
Nucleotides ___________DNA
DNA winds into Chromatin
Chromatin condenses into Chromosomes
Chromosomes _________ Genes
Genes are sections of DNA
DNA is made of nucleotides
Chromosomes contain
Instructions for making
YOU!!!
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• If you unraveled all your chromosomes
from all of your cells and laid out the
DNA end to end, the strands would
stretch from the Earth to the Moon
about _______________.
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• RNA has a different sugar than DNA
• RNA = ribonucleic acid
• It’s components are :
1. _________ (sugar)
2. phosphate group
3. nitrogen base
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• It also has different bases than DNA
adenine --- _________
cytosine --- guanine
• RNA is also single stranded, not double
stranded like DNA.
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DNA
RNA
- _________stranded
- Single stranded
- Sugar =
deoxyribose
- Adenine pairs with
Thymine
- Sugar = ribose
- Adenine pairs with
__________
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I. Why Must DNA Replicate?
• Every time a cell divides, it
must first make a copy of it’s
___________.
• Therefore, each cell
can have a complete set
of chromosomes.
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What are chromosomes???
Nucleotides make up DNA
DNA winds into Chromatin
Chromatin condenses into Chromosomes
Chromosomes contain Genes
Genes are sections of DNA
DNA is made of nucleotides
Chromosomes contain
Instructions for making
YOU!!!
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• Without replication, species could not
survive and individuals could not
successfully grow and _____________.
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II. How DNA Replicates
• DNA is a molecule composed of TWO
strands, each consisting of a sequence of
___________.
• The order of the nitrogen bases on one
strand mandates the sequence of bases
on the ______________ strand.
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If you know the bases on one strand, you can predict which bases
will occur on the complementary strand.
A
G
T
C
C
C
T
-----------------------------
T
C
A
G
G
G
A
This is as
easy as
break
dancing!
During Replication each strand serves as a template to create a
new strand.
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III. Steps In
Replication
1) __________ break
down the hydrogen
bonds between the
two DNA strands,
unzipping the
molecule
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2) As the DNA unzips,
free nucleotides
(from surroundings
in the nucleus)
bond to the single
strands by
________________
(A-T, G-C)
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3) Another Enzyme bonds the new
nucleotides into a chain
** The result of this process is the
formation of TWO DNA molecules, each
____________to the original molecule.
Replication! Rah,Rah, Rah!
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New Strand
Original strand
DNA Replication
Nitrogen Bases
Growth
Growth
Replication Fork
Replication Fork
DNA Polymerase
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1. What are the two types of nucleic acids?
2. What are the three components of a
nucleotide?
3. What are the similarities between DNA and
RNA? What are the differences?
4. Describe the process of DNA replication.
5. Why does a DNA molecule undergo
replication?
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