AP Bio
10/04/04
Itinerary 10/05/04
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Due Today: Writing an Essay for the AP Exam
Topics for today
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Review
DNA Replication
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Overview
Messelson-Stahl Experiments
In Detail
Worksheet- This worksheet is due next Tuesday, 10/12
Itinerary 10/06/04
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DNA Transcription
DNA Translation
Discussion of next week’s laboratory
Review
1. Name the four classes of biomolecules
Review
1. Name the four classes of biomolecules
2. Define ‘monomer’ and ‘polymer.’
Review
1. Name the four classes of biomolecules
2. Define ‘monomer’ and ‘polymer.’
3. What is a nucleotide?
Review
1. Name the four classes of biomolecules
2. Define ‘monomer’ and ‘polymer.’
3. What is a nucleotide?
4. What are the three components of a nucleotide?
Structure of DNA/RNA (1)
Three Components
1)Phosphate Group
2)‘Pentose Sugar’
3)Nitrogenous base
Review
1. Name the four classes of biomolecules
2. Define ‘monomer’ and ‘polymer.’
3. What is a nucleotide?
4. What are the three components of a nucleotide?
5. What is the difference between the purines and the
pyrimidines?
Structure of DNA/RNA (8)
You need to remember these!
Review
1. Name the four classes of biomolecules
2. Define ‘monomer’ and ‘polymer.’
3. What is a nucleotide?
4. What are the three components of a nucleotide?
5. What is the difference between the purines and the
pyrimidines?
6. What is the name of this sugar?
Structure of DNA/RNA (3)
Deoxyribose and Ribose are both 5 carbon sugars
Review
1. Name the four classes of biomolecules
2. Define ‘monomer’ and ‘polymer.’
3. What is a nucleotide?
4. What are the three components of a nucleotide?
5. What is the difference between the purines and the
pyrimidines?
6. What is the name of this sugar?
7. Base Pairing
Gary Coleman
Gary Coleman
Guanine-Cytosine
Gary Coleman
Guanine-Cytosine
Gary Coleman
Guanine-Cytosine
Alex Trebek
Adenine-Thymine
DNA ReplicationOverview (1)
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In Text- Pp 287- 297
DNA ReplicationOverview (1)
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In Text- Pp 287- 297
Step 1: The Double Helix is unzipped
DNA ReplicationOverview (1)
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In Text- Pp 287- 297
Step 1: The Double Helix is unzipped
Step 2: Each strand directs the synthesis of two
new strands
DNA ReplicationOverview (1)
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In Text- Pp 287- 297
Step 1: The Double Helix is unzipped
Step 2: Each strand directs the synthesis of two
new strands
Step 3: The individual nucleotides are
connected to form two new strands
DNA ReplicationOverview (2)
DNA ReplicationOverview (3)
DNA ReplicationOverview (4)
DNA ReplicationOverview (5)
Semiconservative Replication (1)
Process of DNA replicationis called ‘semiconservative
replication
Semiconservative Replication (2)
Process of DNA replicationis called ‘semiconservative
replication
Make sure you know this term. You’ll see it again!
Semiconservative Replication (3)
Process of DNA replicationis called ‘semiconservative
replication
This means that in each new double helix of DNA,
one strand was from the parent.
Semiconservative Replication (4)
Semiconservative Replication (5)
Semiconservative Replication (6)
Semiconservative Replication (7)
How do we know that DNA replicates with a
‘Semiconservative’ nature?
Semiconservative Replication (7)
How do we know that DNA replicates with a
‘Semiconservative’ nature?
Any ideas?
Semiconservative Replication (7)
How do we know that DNA replicates with a
‘Semiconservative’ nature?
Any ideas?
Meselson-Stahl experiment tested the three
hypotheses for DNA replication
Semiconservative Replication (8)
Meselson-Stahl Experiment
Semiconservative Replication (8)
Meselson-Stahl Experiment
Where is the 15N found?
Semiconservative Replication (9)
Meselson-Stahl Experiment
Semiconservative Replication (10)
Meselson-Stahl Experiment
Semiconservative Replication (11)
Meselson-Stahl Experiment
Let’s use the flashlight on
DNA Replication
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Remember, DNA replication is the process of
making copies of DNA.
Let’s use the flashlight on
DNA Replication
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Remember, DNA replication is the process of
making copies of DNA.
When would the cell do this?
Let’s use the flashlight on
DNA Replication
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Remember, DNA replication is the process of
making copies of DNA.
When would the cell do this?
Now we need to look at the specifics of DNA
replication, and the enzymes involved in each
step
But First, What’s an Enzyme?
But First, What’s an Enzyme?
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A type of Protein
But First, What’s an Enzyme?
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A type of Protein
Text Definition:
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A class of proteins serving as catalysts, chemical
agents that change the rate of a reaction without
being consumed within the reaction
Step 1: Separation of the Double
Helix
Step 1: Separation of the Double
Helix
DNA Helicase unwinds the double helix
•The site where the enzyme begins
replication is called the origin of
replication.
Step 1: Separation of the Double
Helix
DNA Helicase unwinds the double helix
•The site where the enzyme begins
replication is called the origin of
replication.
•In Prokaryotes (Bacteria), there is a
single origin; in eukaryotes, there are
thousands
Show clip 16.10B
Step 2: Synthesis of complements
Step 2: Synthesis of complements
Enzyme- DNA polymerase
Step 2: Synthesis of complements
Enzyme- DNA polymerase
•DNA polymerase allows the new
nucelotides to be added to the
growing end of the strand one by
one
Step 2: Synthesis of complements
Enzyme- DNA polymerase
•DNA polymerase allows the new
nucelotides to be added to the
growing end of the strand one by
one
•NOTE: This new synthesis always
occurs in the same direction,
5’3’
DNA directionality
DNA directionality
A new nucleotide is
always added to the 3’ end
of the strand
Synthesis of Complementary strands
Synthesis of Complementary strands
Show 16.13leading strand
Then Show 16.13lagging strand
Enzymes Involved
1) Helicase
Enzymes Involved
1)
2)
Helicase
Single Stranded Binding Protein
Enzymes Involved
1)
2)
3)
Helicase
Single Stranded Binding Protein
Primase
Enzymes Involved
1)
2)
3)
4)
Helicase
Single Stranded Binding Protein
Primase
DNA polymerase
Enzymes Involved
1)
2)
3)
4)
5)
Helicase
Single Stranded Binding Protein
Primase
DNA polymerase
Ligase
DNA Replication-Summary