1. DNA: the molecule of heredity

2. Watson and Crick
proposed that DNA was a chain of nucleotides joined together by the nitrogen bases.

3. Contains DNA: The Instructions for Building Proteins
THE NUCLEUS

4. Thymine
Adenine
Guanine
Cytosine

5. Modeling the Structure of DNA
Deoxyribose…black pentagon
Phosphate Group…white tube
Nitrogen Bases

6. Pyrimidines Cytosine Thymine Purines Adenine Guanine
Nitrogen Bases

7. MITOSIS
Before a cell divides is must make a copy of its DNA so that each cell will have a complete set of DNA molecules:

8. The process by which DNA makes an exact copy of itself
Replication

9. process by which mRNA is formed
Transcription

10. DNA
RNA
deoxyribose
ribose
thymine
uracil
double strand
single strand

11. Modeling RNA Structure
Ribose…purple pentagon
Phosphate Group…white tube
Nitrogen Bases

12. Pyrimidines Cytosine Uracil Purines Adenine Guanine
Nitrogen Bases

13. Contains organelles necessary for creating proteins
THE CYTOPLASM

14. Translation or Protein Synthesis
Process by which protein chains are produced from information on the mRNA strand

15. each nucleotide sequence acts as a genetic blueprint for building a protein
The Genetic Code

17. Editing Out Mistakes
Errors in DNA replication are only about 1 in every billion by the END of replication
DURING replication mistakes happen once in every 100,000 bases
This discrepancy exists because the cell’s genetic machinery is often able to correct itself
This is accomplished by the enzyme DNA polymerase

18. Mutations
Permanently changing the DNA structure

19. Substitution
A substitution is a mutation that exchanges one base for another (i.e., a change in a single "chemical letter" such as switching an A to a G). Such a substitution could:

20. Possible Results of Substitution
change a codon to one that encodes a different amino acid and cause a small change in the protein produced.
change a codon to one that encodes the same amino acid and causes no change in the protein produced. These are called silent mutations.
change an amino-acid-coding codon to a single "stop" codon and cause an incomplete protein. This can have serious effects since the incomplete protein probably won't function.

21. Insertion
Insertions are mutations in which extra base pairs are inserted into a new place in the DNA.

22. Deletion
a section of DNA is lost, or deleted

23. Frameshift
Since protein-coding DNA is divided into codons three bases long, insertions and deletions can alter a gene so that its message is no longer correctly parsed. Consider the sentence, "The fat cat sat." Each word represents a codon. If we delete the first letter and parse the sentence in the same way, it doesn't make sense.
In frameshifts, a similar error occurs at the DNA level, causing the codons to be parsed incorrectly. This usually generates truncated proteins that are useless.