Chapter 12

By: Cole, Symone and Mel

12.1 : DNA

•Grffith’s Experiment & Transformation• Transformation is the process when the heat-killed bacteria had passed their disease-causing ability to the harmless strain

Disease-causing bacteria = Dead MouseHarmless bacteria = Lives Heat-killed Disease causing bacteria = Lives BUT when you mix heat killed with harmless = Dies Of Pnuemonia

• Avery & DNA • Avery and other scientists discovered that the

nucleic acid DNA stores and transmits the genetic information from one generation of an organism to the next

• Bacteriophage- its a kind of virus that infects bacteria. To infect a bacteria the virus attaches to the cell and injects its genetic information.

• Hershey & Chase did an experiment with viruses and radioactive markers. They concluded that the genetic material of the bacteriophage was DNA, not protein.

The Components & Structure of DNA

• DNA is a long molecule made up of units called nucleotides

Summary Of Scientists

• Griffith: Transformation • Avery: Determines that genes are composed of DNA• Franklin: studied DNA molecule by using X-Ray

Diffraction • Watson & Crick: double helix structure of DNA• Brenner: Discover messenger RNA• Gilbert: methods to read the DNA sequence• Human Genome Project: completed attempt to

sequence all human DNA

12.2 : Chromosomes & DNA Replication

• Prokaryotic cells - DNA molecule are located in the cytoplasm

• Chromatin: DNA and protein in chromosomes • Histones: a type of protein • Replication: When a cell duplicates its DNA• During replication, the DNA splits into two strands,

and then produces two new strands, which serves as a template.

• DNA polymerase: joins individual nucleotides to produce DNA molecules

12.3 : RNA & Protein Synthesis

• Genes: coded DNA instructions that control the production of proteins in a cell

• 3 types of RNA: Messenger RNA, Ribosomal RNA, and Transfer RNA

• Transcription: a process when RNA molecules are produced by copying part of the nulceotide sequence of DNA into a sequence of RNA

• Promoters: regions that the enzymes bind to

12.3...

• Introns (nucleotide) & Exons (proteins) • Codon: consists of 3 consecutive nucleotides,

they represent the different amino acids • Translation: when the cell uses info from the

messenger RNA to produce proteins