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DNA: The Genetic Material
Date Assignment Points Earned Possible Points
Chapter 9 Vocabulary 13
Chapter 9 Notes
Chapter 9 Questions
Directed Reading 9-2
DNA Structure Skills Worksheet
Biology Homework: DNA/Concept Map
Directed Reading 9-3
Active Reading 9-3
Chapter 9 DNA: The Genetic Material
Vocabulary Use the glossary and dont shorten the definition. If a page number is listed, use that page to
define the term.
Section 1: Identifying the Genetic Material
1. vaccine -
Section 2: The Structure of DNA
5. double helix
8. base-pairing rules
9. complementary base pair
Section 3: The Replication of DNA
10. DNA replication
11. DNA helicase
12. replication fork
13. DNA polymerase
PowerPoint Notes on Chapter 9 - DNA: The Genetic Material Section 1 Identifying the Genetic Material Objectives
Relate Griffiths conclusions to the observations he made during the transformation experiments.
Summarize the steps involved in Averys transformation experiments, and state the results.
Evaluate the results of the Hershey and Chase experiment.
Transformation : Griffiths Experiments
In 1928, ______________________________, a bacteriologist, was trying to prepare a
____________________ against pneumonia.
A vaccine is a substance that is prepared from _______________ or _______________
disease causing agents, including certain bacteria.
The vaccine is introduced into the body to _________________ the _______________
against future infections by the disease-causing agent.
Griffith discovered that ___________________ bacteria could turn virulent when mixed
with bacteria that cause disease.
A bacteria that is virulent is _____________________________________.
Griffith had discovered what is now called _______________________, a change in
genotype caused when cells take up foreign genetic material.
Griffiths Discovery of
Transformation: Averys Experiments
In 1944, a series of experiments showed:
o The activity of the material responsible for transformation is not affected by
o HOWEVER, the activity IS stopped by a ________ -destroying enzyme.
Thus, almost 100 years after Mendels experiments, Oswald Avery and his co-workers
demonstrated that __________ is the material responsible for transformation.
Viral Genes and DNA: DNAs Role Revealed
In 1952, Alfred Hershey and Martha Chase used the
bacteriophage T2 to prove that ___________ carried
A ___________________, also referred to as a phage, is
a _______________ that infects bacteria.
When phages infect bacterial cells, the phages are able
to ______________________________, which are
released when the bacterial cells rupture.
Hershey and Chase carried out the following
o Step 1 T2 phages were labeled
o Step 2 The phages infect E. coli
o Step 3 Bacterial cells were spun to
remove the virus's ____________
Hershey and Chase concluded that the
_________ of viruses is injected into the
bacterial cells, while most of the _______
__________________ remain outside.
The injected DNA molecules cause the
bacterial cells to produce more ________
_________ and proteins.
This meant that the DNA, rather than
_________________, at least in viruses.
Section 2 The Structure of DNA
Describe the three components of a nucleotide.
Develop a model of the structure of a DNA molecule.
Evaluate the contributions of Chargaff, Franklin, and Wilkins in helping Watson and Crick determine the double-helical structure of DNA.
Relate the role of the base-pairing rules to the structure of DNA.
A Winding Staircase
Watson and Crick determined that a DNA molecule is a ____________________ two
strands twisted around each other, like a winding staircase.
_______________________ are the subunits that make up DNA. Each nucleotide is
made of three parts: a phosphate group, a five-carbon sugar molecule, and a nitrogen-
The five-carbon sugar in DNA nucleotides is called ____________________________.
The nitrogen base in a nucleotide can be either a bulky, _________________________,
or a smaller, _______________________________.
Structure of a Nucleotide
Discovering DNAs Structure:
In 1949, Erwin Chargaff observed that for each organism he studied, the amount of
_______________ always equaled the amount of ________________ (A=T).
Likewise, the amount of ______________ always equaled the amount of ____________
However, the amount of adenine and thymine and of guanine and cytosine __________
between different organisms.
Wilkins and Franklins Photographs
By analyzing the complex patterns on
photo, scientists can determine the
structure of the molecule.
In 1952, Maurice Wilkins and Rosalind
Franklin developed high-quality _________
diffraction photographs of strands of _____.
These photographs suggested that the DNA
molecule resembled a tightly coiled ____________ and was composed of two or three
chains of ______________________.
Watson and Cricks DNA Model
In 1953, Watson and Crick built a model of DNA with the configuration of a __________
________________, a spiral staircase of two strands of nucleotides twisting around a
The double-helical model of DNA takes into account __________________ observations
and the __________________ on Franklins X-ray diffraction photographs.
Pairing Between Bases
An _________________ on one strand always pairs with a ______________ on the
opposite strand, and a _______________ on one strand always pairs with a _________
on the opposite strand.
These _________-_____________________________ are supported by Chargaffs
The strictness of base-pairing results in two strands that contain ___________________
The diagram of DNA below the helix makes it easier to visualize the base-pairing that
occurs between DNA strands.
*3 Things that determine how DNA base pairs bond:
Section 3 The Replication of DNA Objectives
Summarize the process of DNA replication.
Describe how errors are corrected during DNA replication.
Compare the number of replication forks in prokaryotic and eukaryotic DNA.
Roles of Enzymes in DNA Replication
The complementary structure of DNA is used as a basis to ______________________
The process of making a copy of DNA is called _________________________.
DNA replication occurs during the ____________________ phase of the cell cycle,
before a cell divides.
DNA replication occurs in three steps:
o Step 1 ________________________________opens the double helix by breaking
the _____________ bonds that link the complementary nitrogen bases between the
two strands. The areas where the double helix separates are called
o Step 2 At the replication fork, enzymes known as ___________________________
move along each of the DNA strands. DNA polymerases add __________________
to the exposed nitrogen bases, according to the ________________________ rules.
o Step 3 Two ________ molecules form that are _________________ to the original
Checking for Errors
In the course of DNA replication, _________________________ sometimes occur and
the wrong ___________________________ is added to the new strand.
An important feature of DNA _______________________ is that DNA polymerases
have a ____________________________ role.
This proofreading reduces errors in DNA replication to about _______________ error
per 1 billion nucleotides.
The Rate of Replication
Replication does NOT begin at one end of the DNA molecule and end at the other.
The ____________________ DNA molecules found in ________________________
usually have two replication forks that begin at a single point.
The replication forks move away from each other until they meet on the opposite side of
the DNA circle.
In ________________________ cells, each chromosome contains a single, long strand
Each _______________________ chromosome is replicated in about 100 sections that
are 100,000 ___________________________ long, EACH section with its own starting
With multiple replication forks working in concert, an entire human chromosome can be
replicated in about ____________ ho