Download 12.2 Powerpoint

Do Now
True or False? Correct the false
statements.
The first cloned animal was a tadpole.
You inherit more from your father if you are a
boy.
Identical twins do NOT have the same DNA.
All humans share 75% of their DNA.
Objectives
SWBAT identify the parts of a nucleotide
SWBAT label the different parts of a DNA
molecule.
DNA
DNA stands for:
Deoxyribonucleic acid
DNA is located:
In the nucleus of cells
The function of DNA is to:
Tells the cells how to produce things that make
you up (Blueprint)
DNA Structure
Nucleotide is made of:
5 carbon sugar (Deoxyribose)
Phosphate Group
Nitrogen base (adenine, cytosine, guanine,
thymine)
Nitrogen Bases
DNA Structure
DNA Structure
DNA often is compared
to a twisted ladder.
Rails of the ladder are
represented by the
alternating deoxyribose
and phosphate.
The pairs of bases
(cytosine–guanine or
thymine–adenine) form
the steps.
Base PairsRungs of the
ladder
-2 Strands of
DNA form a
helix
Orientation of DNA- Anti Parallel
 On the top rail, the strand is said to be
oriented 5′ to 3′.
 The strand on the bottom runs in the
opposite direction and is oriented 3′ to 5′.
Do Now (#1 and 6 refer to the ends of DNA)
Objectives
1. SWBAT identify the parts of a nucleotide
2. SWBAT create their own strand of DNA
using template sugar, phosphate, and
bases.
Lab
PICK UP:
One sequence per group
One packet per group
2 question worksheets
HANDING IN:
 1 DNA diagram
 2 Sets of questions.
A good way to study
http://www.dnai.org/timeline/index.html
Do Now
Where is DNA located?
What is the role of DNA in the cell?
Objectives
1. SWBAT read and understand the
discovery of DNA by several scientists.
2. SWBAT understand how viruses
replicate and be able to apply this
knowledge to a problem.
When was DNA discovered?
We are going to study the scientists who
helped to discover DNA.
We are going to take turns reading around
the room and taking notes.
Bacterial Transformation
Why do we care about bacterial
transformation?
Genetic
Research
Antibiotic
Resistance
1928 Fred Griffith Studied two strains of bacteria,
Streptococcus pneumoniae
Worked with two strains of bacteria:
Rough Strain and Smooth Strain
S strain causes pneumonia and the R
strain does not
Griffith Cont.
S strain:
Heat killed S strain:
R Strain:
Heat killed S strain + R Strain:
1928 Fred Griffith Discovered that something from the
heat killed wild type (smooth)
bacteria was turning the mutant
(rough) type bacteria into smooth.
Called it the transforming factor
Didn’t really know what it was
Let’s Talk a little about DNA.
Do now period 6
What is DNA?
Where is DNA found?
What do scientists know about our DNA?
How do we apply this DNA technology?
Objectives
SWBAT list and identity the characteristics
of viruses
SWBAT label a diagram of the life cycle of
a virus
SWBAT explain Hershey and Chases
experiment and it’s importance to the
discovery of DNA
Avery
Identified the molecule that transformed
the R strain of bacteria into the S strain
Concluded that when the S cells were
killed, DNA was released
R bacteria incorporated this DNA into their
cells and changed into S cells.
Many people did not believe that it was
DNA, not protein that transformed genes
Viruses- Six Characteristics of Viruses
1. Have their own genome (genetic make
up) made of either DNA or RNA
2. Does not have enzymes, ribosomes, or
ATP
3. Have external protein shells (capsids)
Viruses- Six Characteristics of Viruses
4. Infect only specific cells
5. 2 life cycles (lytic and lysogenic)
Lytic – breaks out and spreads
Lysogenic- hangs around
6. Smaller than bacteria
When a virus attacks a cell…
Let’s try to put these in order….
Lytic vs. Lysogenic Cycle
Hershey and Chase
Used radioactive labeling to trace the DNA
and protein
Concluded that the viral DNA was injected
into the cell and provided the genetic
information needed to produce new
viruses
Hershey and Chase
Radioactive Labeling:
Used radioactive phosphorus (32P) to identify
DNA in the bacteriophages
Used radioactive sulfer (35S) to identify proteins
in the bacteriophages
Hershey and Chase
Tracking DNA
Radioactive bacteriophages infected
bacteria cells
After review results found radioactive
sulfur outside of bacteria cells and
radioactive phosphorus inside bacteria
cells
Hershey and Chase
Do Now
1. What is a virus?
2. Why is a virus NOT considered a living
thing?
3. What are the two types of life cycles of
viruses? Briefly describe each.
Do Now – Period 8
1. Briefly describe Griffith’s experiment
2. What did he conclude?
Chapter
12
Molecular Genetics
DNA Structure
Levene discovered that DNA is made of
nucleotides
DNA Structure
Nucleotide is made of:
5 carbon sugar (Deoxyribose)
Phosphate Group
Nitrogen base (adenine, cytosine, guanine,
thymine)
Nitrogen Bases
DNA Structure
Do Now
1. Briefly describe hershey and chase’s
experiment.
What did they conclude?
Do Now
1. Find the complementary sequence of DNA:
ATCGGATATAGC
2. What bonds form between the sides of DNA?
3. What type of sugar is in DNA?
4. What does 3’ mean?
DNA Structure
DNA often is compared
to a twisted ladder.
Rails of the ladder are
represented by the
alternating deoxyribose
and phosphate.
The pairs of bases
(cytosine–guanine or
thymine–adenine) form
the steps.
Label the parts of the DNA molecule
Base PairsRungs of the
ladder
-2 Strands of
DNA form a
helix
Orientation of DNA- Anti Parallel
 On the top rail, the strand is said to be
oriented 5′ to 3′.
 The strand on the bottom runs in the
opposite direction and is oriented 3′ to 5′.
Do Now (#1 and 6 refer to the ends of DNA)
Do Now –
Hershey and Chase Experiment
What did radioactive phosphorous
indicate?
What did radioactive sulfur indicate?
What was the conclusion of this
experiment?
Objectives
SWBAT explain what Chargaff, Franklin,
and Watson/Crick discovered.
SWBAT create a timeline of the scientists
that discovered DNA.
SWBAT label parts of the DNA molecule
SWBAT describe how a chromosome
coils.
Erwin Chargaff
Chargaff’s rule:
C = G and T = A
Rosiland Franklin
X-ray Diffraction use of
photo 51
X-ray diffraction data helped
solve the structure of DNA
Indicated that DNA was a
double helix
X-Ray Crystallography
Watson and Crick
Built a model of the double helix that
conformed to the others’ research
 two outside strands consist of alternating
sugar and phosphate molecules
 cytosine and guanine bases pair to each other
by three hydrogen bonds
 thymine and adenine bases pair to each
other by two hydrogen bonds
THINK-PAIR-SHARE
Create a timeline of all the scientists and
what they discovered.
Chromosome Structure
DNA coils around histones (proteins) to form
nucleosomes,
This coils to form chromatin fibers.
The chromatin fibers supercoil to form
chromosomes that are visible in the metaphase
stage of mitosis.
Do Now
How do you think your DNA gets in every
cell of your body? Explain.
Objectives
SWBAT define semiconservative
replication, helicase, ligase, DNA
polymerase, and replication.
SWBAT explain how DNA Replicates
SWBAT extract DNA out of a strawberry.
Semiconservative Replication
 Parental strands of DNA separate
 Each strand serve as template
 DNA molecules produced have one strand
of parental DNA and one daughter strand
Steps to DNA Replication
1. Unwinding
DNA helicase (enzyme) unwinds and
unzips the DNA – breaking the hydrogen
bonds between the strands
RNA primase adds a short segment of
RNA, called an RNA primer, on each DNA
strand.
Steps to DNA Replication
2. Base Pairing
DNA polymerase (enzyme) adds
complementary nucleotides to parent DNA
strand
Only adds to 3’ end of new DNA strand
2. Base Pairing (cont.)
Two daughter strands of DNA are made
differently
Leading Strand- Built continuously with out
breaks
Lagging Strand- makes several small
fragments of DNA
Built discontinuously
Pieces are called Okazaki Fragments
Fragments are connected by DNA Ligase
DNA Replication
Steps to DNA Replication
3. Joining
DNA Polymerase removes RNA Primer
and fills it in place with DNA nucleotides
DNA ligase links two sections
Do Now
What is DNA replication?
Why is it called semiconservative?
What is DNA helicase?
Do Now
Label the DNA Replication Diagram
Do Now
Label the DNA strands.
Animations of DNA Replication
http://www.stolaf.edu/people/giannini/flashani
mat/molgenetics/dna-rna2.swf
http://www.johnkyrk.com/DNAreplication.html
http://www.fed.cuhk.edu.hk/~johnson/teachin
g/genetics/animations/dna_replication.htm
Let’s Practice
Do Now – period 3
Let’s practice making an exact copy!
Comparing DNA Replication in
Eukaryotes and Prokaryotes
Eukaryotic DNA unwinds in multiple areas
as DNA is replicated.
In prokaryotes, the circular DNA strand is
opened at one origin of replication.
Do Now
Write down the steps of DNA replication.
Do Now – label A, T, C, G