Interest Grabber

1
Interest Grabber
Section 12-1

• Genes are made of DNA, a large, complex molecule.
  DNA is composed of individual units called
  nucleotides. Three of these units form a code.
  The order, or sequence, of a code and the type of
  code determine the meaning of the message.

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• 1. On a sheet of paper, write the word cats. List
  the letters or units that make up the word cats.
• 2. Try rearranging the units to form other words.
  Remember that eachnew word can have only three
  units. Write each word on your paper, and then
  add a definition for each word.
• 3. Did any of the codes you formed have the same
  meaning?
• 4. How do you think changing the order of the
  nucleotides in the DNA codon changes the codons
  message?

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Section Outline
Section 12-1

• 121 DNA-The search for the molecular nature of
  a gene.
• A. Griffith and Transformation-1928.
• Griffiths Experiments.
• Searching for cure for pneumonia.
• 2 types-smooth (disease causing) and rough (did
  not cause disease.

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Section Outline
Section 12-1

• 2. Transformation-Griffith discovered that live,
  rough pneumonia bacteria would become smooth,
  pneumonia-causing bacteria if mixed with the
  killed smooth bacteria.

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Section Outline
Section 12-1

• B.Avery and DNA.
• 1944.
• Repeated Griffiths experiments.
• Added the twist of destroying all molecules
  except DNA. Bacteria still transformed.
• Then also destroyed the DNA. Bacteria did NOT
  transform.
• Concluded that DNA caused the transformation.

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Section Outline
Section 12-1

• C.The Hershey-Chase Experiment-1952-Used Viruses.
• 1.Bacteriophages-bacteria eating virus.
• 2. Radioactive Markers used to show that it was
  the viral DNA which destroyed the bacteria.

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Section Outline
Section 12-1

• D.The Components and Structure of DNA.
• Made of nucleotides.
• Phosphate.
• Sugar.
• Base.
• Purines-2 rings.
• Adenine Guanine..
• Pyrimidines-1 ring.
• Cytosine Thymine

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Section Outline
Section 12-1

• 1.Chargaffs Rules.
• Adenine bonds to thymine.
• Cytosine bonds to guanine.
• 2.X-Ray Evidence.
• Rosilind Franklin.
• 3.The Double Helix.
• James Watson and Francis Crick.

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Video 1
Video 1
Griffiths Experiment
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Percentage of Bases in Four Organisms
Section 12-1
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 2
9.4 19.9 19.8
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Figure 122 Griffiths Experiment
Section 12-1
Heat-killed, disease-causing bacteria (smooth
colonies)
Harmless bacteria (rough colonies)
Control(no growth)
Harmless bacteria (rough colonies)
Heat-killed, disease-causing bacteria (smooth
colonies)
Disease-causing bacteria (smooth colonies)
Dies of pneumonia
Dies of pneumonia
Lives
Lives
Live, disease-causingbacteria (smooth colonies)
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Figure 122 Griffiths Experiment
Section 12-1
Heat-killed, disease-causing bacteria (smooth
colonies)
Harmless bacteria (rough colonies)
Control(no growth)
Harmless bacteria (rough colonies)
Heat-killed, disease-causing bacteria (smooth
colonies)
Disease-causing bacteria (smooth colonies)
Dies of pneumonia
Dies of pneumonia
Lives
Lives
Live, disease-causingbacteria (smooth colonies)
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Figure 124 Hershey-Chase Experiment
Section 12-1
Bacteriophage with phosphorus-32 in DNA
Phage infectsbacterium
Radioactivity inside bacterium
Bacteriophage with sulfur-35 in protein coat
Phage infectsbacterium
No radioactivity inside bacterium
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Figure 124 Hershey-Chase Experiment
Section 12-1
Bacteriophage with phosphorus-32 in DNA
Phage infectsbacterium
Radioactivity inside bacterium
Bacteriophage with sulfur-35 in protein coat
Phage infectsbacterium
No radioactivity inside bacterium
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Figure 124 Hershey-Chase Experiment
Section 12-1
Bacteriophage with phosphorus-32 in DNA
Phage infectsbacterium
Radioactivity inside bacterium
Bacteriophage with sulfur-35 in protein coat
Phage infectsbacterium
No radioactivity inside bacterium
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Figure 125 DNA Nucleotides
Section 12-1
Purines
Pyrimidines
Adenine
Guanine
Cytosine
Thymine
Phosphate group
Deoxyribose
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Figure 127 Structure of DNA
Section 12-1
Nucleotide
Hydrogen bonds
Sugar-phosphate backbone
Key Adenine (A) Thymine (T) Cytosine (C) Guanine
(G)
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Interest Grabber
Section 12-2

• A Perfect Copy
• When a cell divides, each daughter cell receives
  a complete set of chromosomes. This means that
  each new cell has a complete set of the DNA code.
  Before a cell can divide, the DNA must be copied
  so that there are two sets ready to be
  distributed to the new cells.

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Interest Grabber continued
Section 12-2
1. On a sheet of paper, draw a curving or
zig-zagging line that divides the paper into two
halves. Vary the bends in the line as you draw
it. Without tracing, copy the line on a second
sheet of paper. 2. Hold the papers side by side,
and compare the lines. Do they look the
same? 3. Now, stack the papers, one on top of the
other, and hold the papers up to the light. Are
the lines the same? 4. How could you use the
original paper to draw exact copies of the line
without tracing it? 5. Why is it important that
the copies of DNA that are given to new daughter
cells be exact copies of the original?
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Section Outline
Section 12-2

• 122 Chromosomes and DNA Replication
• A. DNA and Chromosomes
• 1. DNA Length
• 2. Chromosome Structure
• B. DNA Replication
• 1. Duplicating DNA
• 2. How Replication Occurs

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Prokaryotic Chromosome Structure
Section 12-2
Chromosome
E. coli bacterium
Bases on the chromosome
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Figure 12-10 Chromosome Structure of Eukaryotes
Section 12-2
Nucleosome
Chromosome
DNA double helix
Coils
Supercoils
Histones
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Figure 1211 DNA Replication
Section 12-2
Original strand
DNA polymerase
New strand
Growth
DNA polymerase
Growth
Replication fork
Replication fork
Nitrogenous bases
New strand
Original strand
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Video 2
Video 2
DNA Replication
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Interest Grabber
Section 12-3

• Information, Please.
• DNA contains the information that a cell needs to
  carry out all of its functions. In a way, DNA is
  like the cells encyclopedia. Suppose that you go
  to the library to do research for a science
  project. You find the information in an
  encyclopedia. You go to the desk to sign out the
  book, but the librarian informs you that this
  book is for reference only and may not be taken
  out.

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• 1. Why do you think the library holds some books
  for reference only?
• 2. If you cant borrow a book, how can you take
  home the information in it?
• 3. All of the parts of a cell are controlled by
  the information in DNA, yet DNA does not leave
  the nucleus. How do you think the information in
  DNA might get from the nucleus to the rest of the
  cell?

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Section Outline
Section 12-3

• 123 RNA and Protein Synthesis
• A. The Structure of RNA (CM)
• B. Types of RNA
• C. Transcription
• D. RNA Editing
• E. The Genetic Code (chart)
• F. Translation (video)
• G. The Roles of RNA and DNA
• H. Genes and Proteins

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Concept Map
Section 12-3
RNA
can be
also called
which functions to
also called
also called
which functions to
which functions to
from
to
to make up
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Figure 1214 Transcription
Section 12-3
Adenine (DNA and RNA) Cystosine (DNA and
RNA) Guanine(DNA and RNA) Thymine (DNA
only) Uracil (RNA only)
RNApolymerase
DNA
RNA
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Video 3
Video 3
DNA Transcription
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Figure 1217 The Genetic Code
Section 12-3
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Figure 1218 Translation
Section 12-3
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Figure 1218 Translation (continued)
Section 12-3
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Video 4
Video 4
Protein Synthesis
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Interest Grabber
Section 12-4

• Determining the Sequence of a Gene.
• DNA contains the code of instructions for cells.
  Sometimes, an error occurs when the code is
  copied. Such errors are called mutations.

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Interest Grabber continued
Section 12-4
1. Copy the following information about Protein
X MethioninePhenylalanineTryptophanAsparagine
IsoleucineSTOP. 2. Use Figure 1217 on page 303
in your textbook to determine one possible
sequence of RNA to code for this information.
Write this code below the description of Protein
X. Below this, write the DNA code that would
produce this RNA sequence. 3. Now, cause a
mutation in the gene sequence that you just
determined by deleting the fourth base in the DNA
sequence. Write this new sequence. 4. Write the
new RNA sequence that would be produced. Below
that, write the amino acid sequence that would
result from this mutation in your gene. Call this
Protein Y. 5. Did this single deletion cause much
change in your protein? Explain your answer.
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Section Outline
Section 12-4

• 124 Mutations
• A. Kinds of Mutations
• 1. Gene Mutations (chart-Video)
• Point Mutations (video)
• Frameshift Mutations
• 2. Chromosomal Mutations-pg. 308, fig. 12-21.
  (chart-video)
• B. Significance of Mutations

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Video 7
Video 7
Point Mutations
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Gene Mutations Substitution, Insertion, and
Deletion
Section 12-4
Deletion
Substitution
Insertion
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Figure 1220 Chromosomal Mutations
Section 12-4
Deletion
Duplication
Inversion
Translocation
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Video 5
Video 5
Duplication and Deletion
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Video 6
Video 6
Translocation and Inversion

• .

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Interest Grabber
Section 12-5

• Regulation of Protein Synthesis
• Every cell in your body, with the exception of
  gametes, or sex cells, contains a complete copy
  of your DNA. Why, then, are some cells nerve
  cells with dendrites and axons, while others are
  red blood cells that have lost their nuclei and
  are packed with hemoglobin? Why are cells so
  different in structure and function? If the
  characteristics of a cell depend upon the
  proteins that are synthesized, what does this
  tell you about protein synthesis? Work with a
  partner to discuss and answer the questions that
  follow.

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Interest Grabber continued
Section 12-5
1. Do you think that cells produce all the
proteins for which the DNA (genes) code? Why or
why not? How do the proteins made affect the type
and function of cells? 2. Consider what you now
know about genes and protein synthesis. What
might be some ways that a cell has control over
the proteins it produces? 3. What type(s) of
organic compounds are most likely the ones that
help to regulate protein synthesis? Justify your
answer.
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Section Outline
Section 12-5

• 125 Gene Regulation
• A. Gene Regulation An Example
• B. Eukaryotic Gene Regulation
• C. Development and Differentiation

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Typical Gene Structure
Section 12-5
Promoter(RNA polymerase binding site)
Regulatory sites
DNA strand
Start transcription
Stop transcription
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Video Contents
Videos

• Click a hyperlink to choose a video.
• Griffiths Experiment
• DNA Replication
• DNA Transcription
• Protein Synthesis
• Duplication and Deletion
• Translocation and Inversion
• Point Mutations

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Internet
Go Online

• Interactive test
• Articles on genetics
• For links on DNA, go to www.SciLinks.org and
  enter the Web Code as follows cbn-4121.
• For links on DNA replication, go to
  www.SciLinks.org and enter Web Code as follows
  cbn-4122.
• For links on protein synthesis, go to
  www.SciLinks.org and enter the Web Code as
  follows cbn-4123.

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Section 1 Answers
Interest Grabber Answers
1. On a sheet of paper, write the word cats.
List the letters or units that make up the word
cats. The units that make up cats are c, a, t,
and s. 2. Try rearranging the units to form
other words. Remember that eachnew word can have
only three units. Write each word on your paper,
and then add a definition for each word. Student
codes may include Act Sat Cat 3. Did any of
the codes you formed have the same
meaning? No 4. How do you think changing the
order of the nucleotides in the DNA codon changes
the codons message? Changing the order of the
nucleotides changes the meaning of the codon.
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Section 2 Answers
Interest Grabber Answers
1. On a sheet of paper, draw a curving or
zig-zagging line that divides the paper into two
halves. Vary the bends in the line as you draw
it. Without tracing, copy the line on a second
sheet of paper. 2. Hold the papers side by side,
and compare the lines. Do they look the
same? Lines will likely look similar. 3. Now,
stack the papers, one on top of the other, and
hold the papers up to the light. Are the lines
the same? Overlaying the papers will show
variations in the lines. 4. How could you use the
original paper to draw exact copies of the line
without tracing it? Possible answer Cut along
the line and use it as a template to draw the
line on another sheet of paper. 5. Why is it
important that the copies of DNA that are given
to new daughter cells be exact copies of the
original? Each cell must have the correct DNA,
or the cell will not have the correct
characteristics.
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Section 3 Answers
Interest Grabber Answers
1. Why do you think the library holds some books
for reference only? Possible answers The books
are too valuable to risk loss or damage to them.
The library wants to make sure the information is
always available and not tied up by one
person. 2. If you cant borrow a book, how can
you take home the information in it? Students
may suggest making a photocopy or taking
notes. 3. All of the parts of a cell are
controlled by the information in DNA, yet DNA
does not leave the nucleus. How do you think the
information in DNA might get from the nucleus to
the rest of the cell? Students will likely say
that the cell has some way to copy the
information without damaging the DNA.
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Section 4 Answers
Interest Grabber Answers
1. Copy the following information about Protein
X MethioninePhenylalanineTryptophanAsparagine
IsoleucineSTOP. 2. Use Figure 1217 on page 303
in your textbook to determine one possible
sequence of RNA to code for this information.
Write this code below the description of Protein
X. Below this, write the DNA code that would
produce this RNA sequence. Sequences may vary.
One example follows Protein X mRNA
AUG-UUU-UGG-AAU-AUU-UGA DNA TAC-AAA-ACC-TTA-TAA-
ACT 3. Now, cause a mutation in the gene sequence
that you just determined by deleting the fourth
base in the DNA sequence. Write this new
sequence. (with deletion of 4th base U) DNA
TAC-AAA-CCT-TAT-AAA-CT 4. Write the new RNA
sequence that would be produced. Below that,
write the amino acid sequence that would result
from this mutation in your gene. Call this
Protein Y. mRNA AUG-UUU-GGA-AUA-UUU-GA Codes
for amino acid sequence Methionine
PhenylalaineGlycineIsoleucinePhenylalanine? 5.
Did this single deletion cause much change in
your protein? Explain your answer. Yes, Protein
Y was entirely different from Protein X.
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Section 5 Answers
Interest Grabber Answers
1. Do you think that cells produce all the
proteins for which the DNA (genes) code? Why or
why not? How do the proteins made affect the type
and function of cells? Cells do not make all of
the proteins for which they have genes (DNA).
The structure and function of each cell are
determined by the types of proteins
present. 2. Consider what you now know about
genes and protein synthesis. What might be some
ways that a cell has control over the proteins it
produces? There must be certain types of
compounds that are involved in determining what
types of mRNA transcripts are made and when this
mRNA translates at the ribosome. 3. What type(s)
of organic compounds are most likely the ones
that help to regulate protein synthesis? Justify
your answer. The type of compound responsible is
probably a protein, specifically enzymes, because
these catalyze the chemical reactions that take
place.
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