Chapter 12 Name ______
DNA
Information and Heredity, the cellular basis of life
12-1: DNA Identifying the Substance of Genes
Frederick Griffith’sExperiments (1920s)
Bacterial Transformation
1. He was studying bacteria that cause______.
2. His experiment led to a discovery of a process a called ______:
- Process in which one strain of bacteria ______into another strain.
Bacterial Viruses- The ______cause of ______.
What role did Bacterial ______play in identifying the ______material?
Oswald Avery (1940s)
1. His goal was to determine what ______was used during ______.
2. By a process of elimination using biological ______, they discovered that
______was the ______factor.
The Hershey – Chase Experiment (Alfred Hershey & Martha Chase 1950s)
1. They did an experiment involving ______to prove the work of both
______& Avery.
2. Viruses are only made of two things:
- ______
- ______
3. In step 1 of their experiment, they tagged ______with radioactive ______to
see if that was the ______factor. It was the transforming factor!!
4. In step 2 of their experiment, they tagged the ______with radioactive _____
to see if that was the ______factor. It was not.
The Role of DNA What is the role of DNA in ______?
The DNA that makes up genes can:
- ______information in the ______
- ______this information in the cells.
- ______this information in the cells.
Studythebook – cell analogyon page 342 of your textbook.A book can ______information, you can ______information from this book and the book after being copied can be ______or ______to others.
12-2: The Structure and components of DNA
- A ______is the ______of a nucleic acid such as _____or RNA.
- It has 3 components:
A ______group.
A 5 carbon sugar called ______
A ______base
The DNA Nucleotide:
3. There are four different bases in DNA:
- ______(A)- ______(T)
- ______(G)- ______(C)
4. These bases are placed in two groups:
- ______(double ring) A & G
- ______(single ring) C & T
5. Chargaff’s Rules of Base Pairing:
- ______pairs with ______- _____ pairs with _____
- a ______will pair with a ______
The Double______:
1. The structure of DNA was discovered through the work of three people:
A. ______ (1950s)
- she used a technique called
______
to show that DNA has two strands that form a ______.
B. James ______& Francis______ (1953)
- They expanded on Franklin’s work by building a ______of DNA.
- Their model had a ______structure
- The helix had a ______-______backbone.
- The ______ were in the ______and held together by ______
______.
Section 12-3:Replication
What is replication?
______
______
The steps:
1. ______ “unzips” the double helix by breaking the
___ bonds between the bases.
- Two helicase enzymes work in opposite directions & form a ______
- The site where the helicase is doing the unzipping is called a ______
The steps:
2. Within the replication bubble, two ______ work
in opposite directions & make a complementary strand of DNA.
3. At the end of replication, there are two ______of DNA.
How does ______replication differ in:
Prokaryoticcells Eukaryoticcells?
-Prokaytoes or ______cells normally have a ______circular strand of ______. Replication starts from a single point and proceeds in 2 directions.
-In Eukaryotes or cells with a ______, replication begins at dozens or even ______of places and proceeds in both directions.
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