Textbook chapter 6 Biology notes
6.1
One gene - one enzyme hypothesis: proposed by beadle and tatum each gene is unique and codes for
the synthesis of a single enzyme
- Single gene determine the production of one enzyme
One gene one polypeptide hypothesis - a proposal that one gene codes for one polypeptide (or protein)
-each protein has a particular amino acid sequence
-Dna consists of nucleotide strands sequence watson and crick
Types of RNA
1. Messenger RNA (mRNA)
- Contains the genetic information of a gene
- Carries it to the protein synthesis
- Provides information that determines the amino acid sequence
The Genetic code
Genetic code:
- A set of rules for determining how genetic information
- the specific coding relationship between bases and the amino acids that they specify (DNA or
RNA bases)
- DNA code =A T C G
- RNA code = A U C G
There are only 4 RNA bases but these can code for the 20 amino acids (combination of 3 called triplet
hypothesis)
Triplet hypothesis - the genetic code consists of a combination of three nucleotides called a codon
Gene expression- the transfer of genetic information from DNA to RNA to protein
transcription - the synthesis of RNA from a DNA template
Connections between DNA RNA protein