1. Chapter #10 10.1 Discovery of DNA 10.2 DNA Structure
10.3 DNA Replication
10.4 Protein Synthesis

2. Griffith’s Experiments

3. Griffith’s Experiments (2)
1928
A mouse injected w/ both heat killed S (virulent) and R types can cause pneumonia
A HEREDITARY FACTOR must be released and taken into the R type
Is this factor protein? DNA? RNA?

4. Avery’s Experiments 1940’s
Wanted to determine if the material that was transforming was protein, DNA or RNA
Protease to destroy protein
Injected w/heat killed S cells and R cells
Able to transform R to S
RNase to destroy RNA
DNase to destroy DNA
Not able to transform R to S

5. Hershey-Chase Experiment
1952
Protein or DNA?
Little protein found
in viruses; all the
DNA was present
DNA!!!!!

6. The Structure of DNA Sugar-Phosphate Backbone Nitrogen Bases
Deoxyribose (sugar found in DNA)
Nitrogen Bases
Adenine
Thymine
Guanine
Cytosine

7. The Structure of DNA (2) Purine Pyrimidine
Double ringed base
Guanine and Thymine
Pyrimidine
Single ringed base
Cytosine and Adenine
Purines must pair with pyrimidines so the helix can be made (it can twist)

8. DNA Deoxyribonucleic acid Contains genes that code for proteins
Involved in heredity

9. Adenine
Nitrogen base in both DNA and RNA
Purine that pairs with thymine in DNA and uracil in RNA

10. Guanine
Nitrogen base in both DNA and RNA
Purine that pairs with cytosine in both DNA and RNA

11. Thymine
Nitrogen base in DNA only
Pyrimidine that pairs with adenine

12. Cytosine
Nitrogen base found in both DNA and RNA

13. Deoxyribose
5 carbon sugar found in DNA
Makes up the backbone of DNA (sides of the ladder)

14. Phosphate Group
Backbone of DNA
Alternates with deoxyribose

15. Hydrogen Bonds
Bond that joins the nitrogen bases together

16. Building block of nucleic acids Contains…
Nucleotide
Building block of nucleic acids
Contains…
5 carbon sugar
Nitrogen base
Phosphate group

17. DNA Carries the Genetic Code

18. Replication
Process of duplicating DNA
Results in 2 DNA molecules (old and new strands mixed)
Replication is said to be semi-conservative

20. DNA Helicase Enzyme responsible for the untwisting of DNA
Starts the replication process

21. DNA Polymerase
Enzyme responsible for attaching the nucleotides in the correct order during replication.

22. DNA RNA Deoxyribose Double stranded Thymine One version Ribose
Single stranded
Uracil
3 versions
Sugar-Phosphate backbone
Nucleic Acids Adenine, Guanine, Cytosine

23. Steps in replication
DNA helicase unwinds the DNA molecule at several spots
Breaks the hydrogen bonds between the bases
DNA polymerase adds new nucleotides
2 new strands
Original strand + new strand = semiconservative model

24. Structure of RNA Uracil – nitrogen base found only in RNA (pyrimidine)
Ribose – 5 carbon sugar found only in RNA

25. Types of RNA
tRNA - transfer
mRNA - messenger
rRNA - ribosomal

26. tRNA Used to carry amino acids to codons on mRNA
Contains the anticodons on one end and an amino acid on the other end

27. mRNA Contain codons Made through transcription in the nucleus
Read by the tRNA during translation in the ctyoplasm

28. Transcription Vs. Translation
Transcription – process of making RNA from DNA in the nucleus of the cell
Translation – process of making proteins
tRNA recognizes codons of the mRNA and attaches the amino acids in the correct sequence for the protein that DNA coded for.

29. Codon Set of 3 bases found on mRNA
Complementary to the anticodon on the tRNA

30. Anticodon Set of 3 bases found on a tRNA molecule
Recognizes the codon on mRNA during translation

31. Amino Acid Building block of a protein
20 different kinds (essential and nonessential)

32. Peptide Bond
Bond that joins amino acids together in the growing polypeptide chain

33. Polypeptide Made through translation
Growing chain of amino acids that transforms into a protein

34. RNA Polymerase
Enzyme responsible for attaching RNA nucleotides in the correct order.

35. Steps of Transcription (in the nucleus)
DNA is the template
RNA polymerase adds the RNA nucleotides
Uracil replaces Thymine
Once transcribed, mRNA leaves the nucleus and enters the cytoplasm
Hooks up with a ribosome to begin translation

36. Steps of Translation Ribosome, mRNA and tRNA needed to begin
Anticodon on tRNA matches with the codon on mRNA
Always begins w/ start codon (AUG)
Adjacent amino acids form peptide bonds
tRNA keeps adding amino acids until the stop codon is read

37. Steps of Translation
tRNA releases the polypeptide chain (it will fold and become a functional protein)
“naked” tRNA molecules find more amino acids and the process starts all over (as certain proteins are needed)