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Chapter 12: DNA and RNA
Elana Jacobs-Pontecorvo
Discoveries about DNA Avery (and other scientists):
experimented with destroying different parts of heat killed bacteria, and found out that:
DNA is a nucleic acidDNA store genetic information DNA transmits genetic information to the next
generation
Elana Jacobs-Pontecorvo
Hershey and Chase:Experimented with bacteriophages. Bacteriophages are viruses that inject their genetic material into the cell. They found that the genetic material was DNA
Elana Jacobs-Pontecorvo
Watson and Crick: made a model of DNA which was a double
helix, like this picture:
Elana Jacobs-Pontecorvo
DNA replication
The DNA molecule unzips into two strands
Each strand produces a new strand
The enzyme used is called DNA polymerase
Elana Jacobs-Pontecorvo
Types of RNA
Messenger RNA: sends messages from DNA to rest of the cell.
Ribosomal RNA: Makes up ribosomes
Transfer RNA: Help construct proteins.
Olenka Alvarado
Transcription
1. The enzyme, RNA polymerase, separates the DNA strands.
2. Nucleotides are made into a strand of RNA, by using a strand of DNA as a model.
Olenka Alavarado
Translation: process of cell making proteins
A) mRNA enters cytoplasm and attaches to ribosome, starts translation.
B) tRNA with an amino acid on top attaches to the mRNA strand with the anticodon that matches its codon.
C) ribosomes form peptide bond between the amino acids
D) tRNA leaves and the cell is left with a protein chain
Olenka Alvarado
Mutations
A) Gene Mutations: change in a single gene-Point Mutations: affect one nucleotide-Frameshift Mutations: affects all
amino acids after the change (insertion or deletion of nucleotide)
B)Chromosomal Mutations: changes in structure or number of chromosomes
Olenka Alvarado
Gene Regulation
Lac genes: turned off by repressors and on by lactose
Eukaryotic Genes: individually controlled.
Olenka Alvarado
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