February 10, 2012
Agenda
• Opening Bellwork
• Discussion of DNA
• Video Clip
– Get out a blank sheet of
paper
• Structure of DNA
– Lecture and Discussion
• Review Exams
Objectives
• I will know the 4 bases and
how they pair up
• I will know the basic
structure of the sugarphosphate backbone.
CHAPTER 12:
DNA and RNA
Building block of DNA
• _____________
Nucleotides are the building block
– Consist of:
• 5-Carbon sugar (Deoxyribose),
• Phosphate group, and
• Nitrogenous base:
Purines (2 Rings)
– Adenine and Guanine : _____________
– Thymine and Cytosine: _____________
Pyrimidines (Only one ring)
• Sugar and Phosphate groups form __________
backbone
while nitrogenous bases ______________
hydrogen bondin
between.
Figure 12–5 DNA Nucleotides
Section 12-1
Purines
Adenine
Guanine
Phosphate
group
Pyrimidines
Cytosine
Thymine
Deoxyribose
Figure 12–7 Structure of DNA
Section 12-1
Nucleotide
Hydrogen
bonds
Sugar-phosphate
backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
The Structure of DNA
= Phosphate
= Deoxyribose
(5-c sugar)
= N-base
(A-T)
(G-C)
Hydrogen bonds
February 14, 2012 <3
Agenda
• Opening Bell Work
– Diagram DNA Structure
• Lecture and Discussion
– Experiments that gave us DNA
• Closing Bell Work
– Most interesting experiment
• Homework:
– 12.1 Outline – 2 Pages
Objectives
• I will be able to summarize
each of the following
peoples experiments and
know why they were
significant to our
understanding of DNA:
–
–
–
–
–
Griffiths
Avery
Hershey and Chase
Franklin and Wilkins
Watson and Crick
Griffith and Transformation
• Griffith was trying to figure out how bacteria
made people sick.
– Specifically, Pneumonia
• 2 Pneumonia strains isolated from mice.
– Smooth
• Did make people sick.
– Rough
• Did NOT make people sick
Rough and smooth Bacteria
Griffiths
• Injected mice with
– disease causing strain – died - X(
– Non-disease causing strain - lived
• Thought it might be poison caused by
bacteria.
• Took disease causing bacteria, heated them to
kill the bacteria, then injected it into mice.
– Lived
Griffiths Transformation
• Mixed heat killed, disease causing bacteria with live
harmless ones
– Injected it into mice
– Neither should make mice sick, but what was the result?
• Mice got pneumonia and died
• Dead, harmful bacteria had passed along ability to
make mice sick to the harmless bacteria
• Known as TRANSFORMATION  one strain of
bacteria has been changed into another. DNA had
been transferred.
Figure 12–2 Griffith’s
Experiment
Section 12-1
Heat-killed,
disease-causing
bacteria (smooth
colonies)
Disease-causing
bacteria (smooth
colonies)
Harmless bacteria Heat-killed, disease(rough colonies) causing bacteria
(smooth colonies)
Dies of pneumonia
Lives
Lives
Control
(no growth)
Harmless bacteria
(rough colonies)
Dies of pneumonia
Live, disease-causing
bacteria (smooth colonies)
Transforming factor altered the Rough (harmless) Bacteria
into Smooth (harmful) Bacteria
Avery, MacLeod and others
• Did the same experiment as Griffith
– except with isolating the biological compounds
• Carbohydrates, Lipids, Proteins and DNA
– See what was necessary for transformation
• Only DNA was necessary for the
transformation to occur; therefore it is the
transforming factor.
• Discovered DNA stores and transmits the
genetic information from one generation to
the next.
Hershey-Chase Experiments
• Alfred Hershey and Martha
Chase (a girl!) studied viruses
– A virus is a non living particle,
smaller than a cell, that can
infect people.
• Bacteriophages are a type of
virus that can infect bacteria.
– Made of DNA or RNA and a
protein
Bacteriophages
• When a bacteriophage enters a bacteria, it
injects genetic material.
– Typically the genetic material is coding to make
more bacteriophages.
– When the bacteria gets too full of bacteriophages,
it splits open and dies.
• releasing TONS more bacteriophages
Hershey-Chase Experiments
• Hershey and Chase wanted to determine what
part of the virus was the infecting agent
– Protein coat or DNA/RNA
• Grew virus’ on a plate with radioactive isotopes.
– Phosphorus – To Tag the DNA (proteins don’t have P)
– Sulfur – To tag the protein (DNA doesn’t have S)
• If they found radioactive P or S in the bacteria
cells, they would know what had been injected
by the virus.
Hershey- Chase – RESULTS!
• Only found radioactive Phosphorus in the
bacteria.
• What does that mean?
– The genetic material of the virus was DNA, not
protein!
Hershey Chase Experiment
Figure 12–4 Hershey-Chase
Experiment
Section 12-1
Bacteriophage with
phosphorus-32 in
DNA
Phage infects
bacterium
Radioactivity inside
bacterium
Bacteriophage with
sulfur-35 in protein
coat
Phage infects
bacterium
No radioactivity inside
bacterium
Validated that DNA is the agent of genes
Chargaff
• Noticed the % of Guanine and Cytosine were
roughly equal
• Noticed the % of Adenine and Thymine were
roughly equal
• No idea why, however
Percentage of Bases in Four
Organisms
Source of DNA
A
T
G
C
Streptococcus
29.8
31.6
20.5
18.0
Yeast
31.3
32.9
18.7
17.1
Herring
27.8
27.5
22.2
22.6
Human
30.9
29.4
19.9
19.8
Rosalind Franklin and Maurice Wilkins
• X-Ray Diffraction
– Beams of high powered
X rays at concentrated
samples of DNA to try
and see structure.
– Received very little
credit and died of cancer
Watson and Crick
• Watson and Crick were together trying to
figure out the structure
– By making cardboard and wire structures.
• Using Franklins X-Ray pictures, they were able
to determine
– DNA is a double helix (2 strands wound around
each other)
– Base pairing explained Chargaffs Rules
Evidence of DNA Structure
• X-Ray Diffraction
– Rosalind Franklin and
Maurice Wilkins
• Chargaff base pairing
– A- T
– G- C
• Watson and Crick Final
DNA model
– Double Helix
– Nobel Prize winners in
1962
February 14, 2012
Agenda
• Opening Bell Work
– Diagram DNA Structure
• Lecture and Discussion
– Experiments that gave us DNA
• Closing Bell Work
– Most interesting experiment
• Homework:
– 12.1 Outline – 2 Pages
Objectives
• I will be able to summarize
each of the following
peoples experiments and
know why they were
significant to our
understanding of DNA:
–
–
–
–
–
Griffiths
Avery
Hershey and Chase
Franklin and Wilkins
Watson and Crick
February 15, 2012
Agenda
• Opening Bell Work
– Summarize each of the
experiments from yesterday
• Lecture and Discussion
– 12.2 – DNA Replication
– DNA Replication Drawing
– Video Clip
• Closing Bell Work
• Write a Paragraph describing the
DNA replication Process
• Homework
– 12.2 Outline (2 Pages)
Objectives
• I will be able to
– summarize and diagram the
process of DNA replication
– know how and when it takes
place
– what enzyme it uses to aid
in the replication process
12-2: Chromosomes and DNA Replication
A. DNA and Chromosomes
lack nuclei
a. Prokaryotes ___________and
their
DNA is found in the cytoplasm.
singular circular DNA
b. It consists of alarge,
_____________________
molecule
c. This is the cells chromosome
______________
d. Eukaryotic DNA is more complicated
e. It is not free in the cytoplasm but is contained in
the _________
nucleus of the cell.
f. It forms a number
_______ of chromosomes not just one
8 and a
g. humans have 46
__, Drosophila have __
22
Sequoia tree have __.
1. DNA Length
a. ______
DNA molecules are surprisingly long
4 million
b. prokaryotes DNA of E. coli is over __
base pairs long.
packed into a space that is onec. it must be ___________________
one thousandths it’s size. (see fig. 12-9)
d. How does it do this?
2. Chromosome Structure
eukaryotic cells is even more tightly
a. DNA in _________________
packed.
6 billion DNA base
b. Eukaryotic DNA has over __________
pairs and is measured at over 1 meter of DNA
c. It is folded into a tiny _____________
chromosome
d. How does it do this?
e. Eukaryotic DNA contains both DNA and
histones
___________(proteins)
packed together to form
____________.
chromatin
2. Chromosome Structure (cont.)
f. Chromatin consists of ______
DNA tightly wrapped around
histones to form a _________
structure called a
beadlike
___________.
nucleosome
g. Nucleosomes pack with one another to form a thick
shortened by a system of
fiber and are ____________
________________.
loops and coils
cell cyclethese fibers are dispersed and
h. During the _________
__________.
not visible
i. During _________
mitosis they are condensed and coiled into
visible chromosomes.
the ________
they are able to
j. What do nucleosomes do? _____________
fold
the DNA into the tiny space of the cell
_______________________________________
_______
nucleus
DNA Supercoiling into Chromosomes
Nucleosome
Chromosome
DNA
double
helix
Coils
Supercoils
Histones
B. DNA Replication
Remember what Watson and Crick learned about DNA:
- Holds the Genetic code in the sequence of nucleotides
-
-
DNA Is double stranded - consists of two parallel
strands of sugar-phosphate groups. Pairs of nitrogenous
bases link the two strands together, forming a
double helix
The Nitrogen (N)-base pairing is complementary
because each strand can be used to make the other
strand.
B. DNA Replication
- In ____________
prokaryotesreplication begins on one point
continues in
on the chromosome and ___________
two
directions
______________
-
In ____________
eukaryotes the DNA replication occurs in
___________
____
hundreds of places and occurs in both
_____________
until each chromosome is copied.
directions
-
The sites where separation and replication occur
are called _______________.
replication forks
The Replication of DNA
Try your own:
AATTTCGATGGC
(Strand 1)
T TAAAG C TAC C G
(Strand 2)
A. Each strand of the double helix
serves as a template, or model, for
the new strand
This aids in DNA replication.
The Replication of DNA
B. Q: Why does DNA need to replicate?
A: When a cell divides to form new
cells, the DNA must REPLICATE
to ensure new cells have a new
copy.
C. DNA replication (aka: DNA synthesis) is
(DNA
done with the aid of Enzymes
.
Polymerase)
The Replication of DNA
D. The Enzymes:
1. Separate or “unzip” the two strands
of the double helix.
2. Insert the appropriate bases.
3. Covalently bond the sugar to the
phosphate
4. Proofread the bases to make sure
they were paired correctly
DNA Replication
New strand
Original
strand
DNA
polymerase
Growth
DNA
polymerase
Growth
Replication
fork
Replication
fork
New strand
Original
strand
Nitrogenous
bases
The Replication of DNA (Summary)
E. The steps in DNA replication
1. The Hydrogen Bonds (between
N-bases) break and “unzips”
the DNA
2. Each strand serves as a
template for the attachment of
complementary bases
The Replication of DNA
Unzip
Base Pairing
2 New Strands
February 15, 2012
Agenda
• Opening Bell Work
– Summarize each of the
experiments from yesterday
• Lecture and Discussion
– 12.2 – DNA Replication
– DNA Replication Drawing
– Video Clip
• Closing Bell Work
• Write a Paragraph describing the
DNA replication Process
• Homework
– 12.2 Outline (2 Pages)
Objectives
• I will be able to
– summarize and diagram the
process of DNA replication
– know how and when it takes
place
– what enzyme it uses to aid
in the replication process
February 16, 2012
Agenda
• Opening Bell Work
– Diagram DNA replication
• Lecture and Discussion
– 12.3a – RNA, Transcription
– Drawing
– Video Clip
• Closing Bell Work
– Summarize Transcription Process
• Homework
– 12.3a (Pgs. 300-303) Outline
– ¾ Page
Objectives
• I will know
– The difference between the types
of RNA
– The definition of transcription and
be able to summarize the process
– Be able to diagram what
transcription would look like.
12-3 RNA and Protein Synthesis
• DNA holds the genetic code to make
proteins
• Proteins are made outside the nucleus on
ribosomes
• DNA Cannot leave the nucleus
• How does DNA get the code outside the nucleus?
A: RNA(Ribonucleic Acid) acts as a
messenger between DNA and the
ribosomes and carries out the
process by which proteins are
made from Amino Acids.
DNA
mRNA
Protein
Protein Synthesis overview
mRNA and DNA interaction
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
RNA
polymerase
DNA
RNA
I. The Structure of RNA
A. Similar to DNA with a few differences:
DNA
RNA
Double Stranded
Single Stranded (can form
double strand if it folds back
on itself).
Strand
Sugar
Bases
Deoxyribose
A-T G-C
Ribose
A-U
G-C
The Structure of RNA
B. 3 types of RNA:
1. mRNA (messenger RNA)
Copies the code off DNA in the nucleus
and brings it out of the nucleus to the
ribosomes
2. tRNA (transfer RNA)
Carries amino acids to the
ribosomes
3. rRNA (ribosomal RNA)
Along with proteins, rRNA makes
the subunits of the ribosomes
Different Forms of RNA
50S
30S
II. Transcription: RNA Synthesis
A. Transcription=
The process by which a
molecule of DNA is copied to a
complementary strand of RNA
Page 147
Transcription: RNA Synthesis
B. Steps of Transcription:
Step #1: RNA polymerase (enzyme) attaches to a
sequence of DNA known as the Promotor and
separates the 2 strands
Step #2: RNA nucleotides base pair with complementary
DNA nucleotides with the help of RNA polymerase
DNA
A
T
C
G
mRNA
U
A
G
C
Transcription: RNA Synthesis
Now try your own:
DNA=
mRNA=
T T T A G A G A C C G T A T C
A A A UC U C U G G C A U A G
**Remember,
Thymine!
RNA does not have
Transcription: RNA Synthesis
Step #3:
RNA polymerase terminates (ends)
transcription when it reaches the
“STOP” site on the DNA
Step #4: The final RNA strand leaves the
nucleus through the pores in the
nuclear envelope
• proteins are responsible for:
– Controlling biochemical pathways(enzymes)
–
Synthesis of lipids, carbohydrates, and
nucleotides
–
Cell structure and cell movement
• DNA and RNA control the process of
making proteins
• DNA
RNA
Transcription
Protein
Protein
Translation Synthesis
Central Dogma
I. THE NATURE OF THE GENETIC CODE
A. Review:
polymers
1. Proteins are ________________
2. Proteins are made of monomers
known as _________________
amino acids
3. There are ___________
different
20
kinds of amino acids
4. Amino acids form ______________
peptide
bonds
5. A string of amino acids is known as
_______________
polypeptide
a
The Nature of the Genetic Code
B. DNA contains
the code to make
proteins
mRNA in
C. The code is copied onto
transcription
D. Every
E. Each
3 nitrogenous bases on the
mRNA makes a codon.
codon specifies an amino acid
that is to be placed in the
polypeptide chain
** the chart on page 303 lists the 64 codons for the amino acids
Start and Stop Codons
The Nature of the Genetic Code
Example:
DNA:
mRNA:
Amino Acid:
T A C C A G
A U G G U C
Methionine
“Start” Codon
Valine
C T C
A C T
G A G U G A
Glutamic
Acid
“Stop”
Codon
F. An amino acid can have more than one
codon
Example: Glycine GGG, GGA, GGU, GGC
The Genetic Code (p. 303)
February 16, 2012
Agenda
• Opening Bell Work
– Diagram DNA replication
• Lecture and Discussion
– 12.3a – RNA, Transcription
– Drawing
– Video Clip
• Closing Bell Work
– Summarize Transcription Process
• Homework
– 12.3a (Pgs. 300-303) Outline
– ¾ Page
Objectives
• I will know
– The difference between the types
of RNA
– The definition of transcription and
be able to summarize the process
– Be able to diagram what
transcription would look like.
February 17, 2012
Agenda
• Opening Bell Work
– Diagram Transcription
• Lecture and Discussion
– 12.3B - Translation
• Quiz
• Homework
– 12.3b (Pages 303-306)
– ¾ Page
Objectives
• I will know
– The difference between
transcription and translation.
– The definition of translation
and be able to summarize the
process.
II. TRANSLATION
A. Translation=
The decoding of a
mRNA into a
polypeptide (protein)
nucleic acid
B. The_______________
language is
___________________
translated
into ________________
protein
language
Translation
KEY PLAYERS
Ribosomal RNA
ANTICODON
Translation
Steps of Translation:
Step #1: After leaving the nucleus,
mRNA binds to the ribosome where rRNA is found
Step #2: In the cytoplasm,
tRNA picks up amino acids and carries them to the mRNA
Step #3: First
the anticodon on tRNA attaches to the mRNA
codon that it matches.
If the mRNA is AUG what will the anticodon be?
Step #4: Then
tRNA continues to match its ANTICODONS with
corresponding mRNA CODONS
Step #5: As each
anticodon and codon bind together, a peptide
bond forms between the 2 amino acids
Step #6: Finally, when
The ribosome reaches the stop codon on the mRNA
the new polypeptide is released
Translation
Translation part 2
http://library.thinkquest.org/C0123260/basic%20knowledge/images/basic%20knowledge/RNA/translation%20steps.jpg
February 17, 2012
Agenda
• Opening Bell Work
– Diagram Transcription
• Lecture and Discussion
– 12.3B - Translation
• Quiz
• Homework
– 12.3b (Pages 303-306)
– ¾ Page
Objectives
• I will know
– The difference between
transcription and translation.
– The definition of translation
and be able to summarize the
process.
February 21, 2012
Agenda
• Quiz Review
• Lecture and Discussion
– 12.3B – Translation
– Diagram Translation
– Video Clip
• Transcription/ Translation
Worksheet
• Closing Bell Work
– Summarize Translation
• Homework
– 12.4 Outline ¾ Page Minimum
Objectives
• I will know
– The difference between
transcription and translation.
– The definition of translation and
be able to summarize the process.
– Diagram the process of
translation.
– How to take a DNA codon and
transcribe it to RNA and translate
it to proteins
February 22, 2012
Agenda
• Opening Bell Work
– Diagram whole process from
DNA to Proteins
• Lecture and Discussion
– Diagram together
– 12.4 – Mutations!
• Closing Bell Work
• Homework
– Review Sheet
Objectives
• I will be able to
– Diagram the entire process a
molecule would take from
DNA mRNA  Protein
– Define different types of
Mutations
12-4 Mutations
Mutations in Genes =
Mutations that occur in individual genes. Can be
changes in several or just one nucleotide
A. Point Mutations = change involving a single
nucleotide
TYPE
DEFINITION
One base is replaced
Base
substitution by another base
EXAMPLE
AGTGGATC
TCACCGAG
Deletion
Nucleotide is removed
AGTGGATC
AGTG|ATC
Insertion
Nucleotide is added
AGGTGGAT|C
AGGTGGATTC
Gene Mutations:
Substitution, Insertion, and Deletion
Substitution
Insertion
Deletion
B. ___________________
Frameshift Mutations = codon groupings are
shifted after deletion or insertion.
Chromosomal Mutations:
Involve the movement of large sections of
chromosome
Deletion
Duplication
Inversion
Translocation
DNA:
ACA ATA TAG CTT TTG ACG GGG AAC CCC ATT
Transcribed into mRNA:
UGU UAU AUC GAA AAC UGC CCC UUG GGG UAA
Translated into Amino Acid Sequence:
Cysteine-Tyrosine-Isoleucine-Glutamic Acid-AsparagineCysteine-Proline- Leucine-Glycine
February 22, 2012
Agenda
• Opening Bell Work
– Diagram whole process from
DNA to Proteins
• Lecture and Discussion
– Diagram together
– 12.4 – Mutations!
• Closing Bell Work
• Homework
– Review Sheet
Objectives
• I will be able to
– Diagram the entire process a
molecule would take from
DNA mRNA  Protein
– Define different types of
Mutations