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What is the evidence that the Gene is DNA?
- DNA from one type of bacterium genetically transforms another type.
- The transforming principal is DNA.
- Viral replication experiments proved that DNA is the genetic material.
- Eukaryotic cells can also be changed by DNA.
What is the circumstantial evidence that DNA is the genetic material?
- Its in the right location.
- It varies among species.
- Its present in the right amount.
What is the transforming principle?
- The chemical substance from one cell is able to genetically transform another cell.
What is the structure of DNA?
Consists of deoxyribose sugar, a phosphate group, and a nitrogenous containing base.
- Antiparallel double helix
- nucleotide base interior and a sugar-phosphate backbone exterior.
- Double stranded
What is DNA polymerase?
An enzyme that catalyzes the reaction of DNA.
What is the DNA template?
A guide to the incoming nucleotides.
What is Semiconservative replication?
When each parent strand serves as a template for a new strand. The two new DNA molecules each have one old strand and one new strand.
What is conservative replication?
The original double helix serves as a template for, but doesn't contribute to, the new double helix. Keeps the old molecule and generates a second entirely new molecule.
What is dispersive replication?
This produces two new DNA molecules that has strands that are both intercepted with old and new DNA.
What are the two general steps in DNA replication?
The DNA double helix is unwound so that the two template strands are separated. They are now available for new complementary base pairing.
As new nucleotides form complementary base pairs with the template DNA, they get covalently linked by phosphodiester bonds.
(these nucleotides are added to the growing new strand at the 3' end.)
How are errors in DNA repaired?
- Proofreading- corrects errors in replication as DNA polymerase makes them.
- Mismatch repair- scans DNA immediately after its replicated and corrects any base pair mismatches.
- Excision repair- removes abnormal bases that have formed from chemical damage and replaces them with functional bases.
How does the Polymerase Chain Reaction amplify DNA?
It copies a short region of DNA, and replicated or (amplifies) it in a test tube.
What is the role of DNA ligase in DNA replication?
To bond Okazaki fragments to one another.