Genes are made of DNA
Define Key Terms:
Genes are made of DNA- (Griffith)
- Griffith was a British Biologist studying two strains (forms) of bacterial species.
- One strain caused Pneumonia, which was deadly to the mice that he used in his experiments, and the other was harmless. (See Figure 11-1)
- When he injected heat-treated bacteria into the mice, the mice remained healthy.
- The heat killed the deadly strain of the bacteria making it harmless.
Avery shows DNA is the transforming factor
- American scientist, Avery took Griffith’s work as step further.
- Avery wanted to test whether protein was the transforming factor, he treated Griffith mixture of heat-treated deadly strain and live harmless strain with protein destroying enzymes.
- From his results, Avery concluded that protein could not be the transforming factor.
- Next they treated the bacteria with DNA destroying enzymes, this time the colonies failed to transform.
- From this, Avery concluded that DNA is the genetic material of cells.
- See Figure 11-2
Virus experiments provide more evidence
- Read pg. 227
- Summary of Hersey & Chase’s work
- Protein coats of phages are radioactively labeled.
- Phages infect bacteria
- No radioactivity enters cell
- DNA of phages is radioactively labeled
- Phages infect bacteria with genetic material
- Radioactivity enters the cell.
- Complete Concept Check 11-1
- Answer question in a complete sentences
- You may use the same paper as your notes.
- We will go over answers together in class
Nucleic Acids store information in their sequences of chemical units
Define Key Terms
- Deoxyribonucleic acid (DNA)
- Nitrogen base
- Double Helix
The Building blocks of DNA
- DNA is a kind of nucleic acid, a polymer built from monomers called peptides.
- Another group of nucleic acids is called Ribonucleic acid (RNA) also plays a key role in cells.
- Nucleotides are the building blocks of nucleic acid polymers.
- Only 4 types of Nucleic acids make up DNA (They are?) See page 230 Figure 11-6
- Each nucleotide has 3 parts: (See Figure 11-5) Draw and label this figure in your notes
- A ringed shaped sugar called deoxyribose
- A phosphate group
- A Nitrogenous base
- The four nucleotide bases found in DNA differ from one another only in their Nitrogen bases.
- Thymine & Cytosine are made of single ringed structures called pyrimidines.
- Adenine & Guanine are larger double ringed structures called purines. Read DNA Strands on p. 230
- Read DNA’S structure on p. 230
- Read The Double Helix on p. 231
- Review Complimentary base pairs on p. 231
- See Fig. 11-7 and 11-8
- Complete 11-2 Concept Check
- Answer questions in complete sentences
- You may answer on the same page as your class notes.
- We will go over answers together in class.