1. Ch 12 DNA and RNA

2. 12-1 DNA
Transformation- one strain of bacteria permanently changes into another strain.

3. 12-1 DNA
Avery and other scientists discovered that DNA stores and transmits the genetic information from one generation to the next.

4. 12-1 DNA Bacteriophage- type of virus that infects bacteria.
Hershey and Chase concluded that the genetic material of the bacteriophage was DNA, not protein.

5. 12-1 DNA
Nucleotides- units that make up DNA, composed of: 1) 5-carbon sugar (deoxyribose)
2) phosphate group
3) nitrogenous base (adenine, cytosine, guanine, or thymine).

6. 12-1 DNA
Watson and Crick’s model of DNA was a double helix, in which two strands were wound around each other.

8. 12-1 DNA
Base pairing- hydrogen bonds can only form between certain base pairs.
adenine=thymine
guanine=cytosine.

9. 12-2 Chromosomes and DNA Replication
Chromatin- substance containing DNA and protein that makes up chromosomes.
Histones- protein that DNA wraps around.

10. 12-2 Chromosomes and DNA Replication
Replication- the copying of DNA before a cell divides.

11. 12-2 Chromosomes and DNA Replication
During DNA replication:
1) the DNA molecule separates into two strands.
2) two new complementary strands are formed following base pairing rules.
3) Each original strand of DNA serves as a template for a new strand.

12. 12-2 Chromosomes and DNA Replication
DNA polymerase- principle enzyme involved in DNA replication. Joins individual nucleotides together to produce a DNA molecule.

13. 12-3 RNA and Protein Synthesis
Genes- coded DNA instructions that control protein production within a cell.

14. 12-3 RNA and Protein Synthesis
RNA is similar to DNA with three major differences:
1) single stranded (instead of double stranded)
2) ribose sugar (instead of deoxyribose)
3) Uracil instead of Thymine (U replaces T)
There are three main types of RNA:
1) messenger RNA (mRNA)
2) ribosomal RNA (rRNA)
3) transfer RNA (tRNA)

15. 12-3 RNA and Protein Synthesis
Messenger RNA- carry copies of DNA instructions to the rest of the cell.

16. 12-3 RNA and Protein Synthesis
Ribosomal RNA- help ribosomes assemble proteins.

17. 12-3 RNA and Protein Synthesis
Transfer RNA- transfers the appropriate amino acids to the ribosome as a protein is made.

18. 12-3 RNA and Protein Synthesis
Transcription- copying part of a DNA sequence into a complementary RNA sequence.

19. 12-3 RNA and Protein Synthesis
During transcription, RNA polymerase:
1) binds to DNA.
2) separates the DNA strands.
3) uses one DNA strand as a template to create an RNA strand.

20. 12-3 RNA and Protein Synthesis
Promoters- Specific regions of DNA where RNA polymerase will bind.

21. 12-3 RNA and Protein Synthesis
Introns- “junk” DNA sequences that do not code for proteins.
Exons- DNA sequences that code for proteins.

22. 12-3 RNA and Protein Synthesis
Codon- three consecutive nucleotides that specify a single amino acid.
*The genetic code is universal*

23. 12-3 RNA and Protein Synthesis
Translation- the process of using the mRNA sequence to produce proteins.
Anticodon- carried on tRNA molecules, complementary to a codon in mRNA.

25. 12-4 Mutations Mutations- changes in the genetic code.
Point mutation- mutation involving one or a few nucleotides.
Frameshift mutation- mutations that shift the “reading frame” of a genetic sequence.

27. 12-4 Mutations Causes of mutations: 1) Spontaneous
2) Chemicals and radiation
3) High energy radiation
(x-rays, gamma rays)

28. 12-5 Gene Regulation Operon- a group of genes that operate together.
The lac genes are turned off by repressors and turned on by the presence of lactose.

29. 12-5 Gene Regulation
Most eukaryotic genes are controlled individually and have regulatory sequences that are much more complex than those of the lac operon.

30. 12-5 Gene Regulation
Differentiation- during embryonic development, cells become specialized in structure and function.
hox genes- a series of genes that control the body plan of many organisms.