One Gene One Polypeptide

1
One Gene One Polypeptide

• CH 11.4

2
One Gene One Polypeptide

• The relationship between genes and proteins came
  from the work of Beadle and Tatum in 1940s
• They proposed ? One Gene-One enzyme hypothesis
• Now stated as One Gene One Polypeptide

3
Information Flow

• Language of DNA is written as a sequence of bases
• If the bases are the letters the genes are the
  sentences
• Information in DNA is made into Protein
• RNA ? carries translates the message in DNA to
  protein
• DNA? RNA ? Protein

4
Flow of information
5
RNA-Ribonucleic Acid

• Single stranded
• Ribose sugar
• Four bases? Adenine, Guanine, Cytosine
  Uracil(U)
• Uracil similar to Thymine and pairs with Adenine

6
Types of RNA

• m RNA? transfers the genetic code of DNA in the
  nucleus to the ribosome in the cytoplasm
• t-RNA ? transfers amino acids to the ribosome to
  make proteins
• r- RNA ? ribosomal RNA

7
Transcription

• The construction of RNA along portions of the DNA
  molecule.
• DNAs nucleotide sequence is converted into a
  single-stranded RNA molecule.

8
Translation

• The process by which the mRNA code is read and
  converted into a specific amino acid sequence.
• This flow of information is based on codons
• Codon? a sequence of three bases that codes for
  one amino acid

9
The Triplet Code

• DNA stores information to make protein ? 20 AAs,
  functional if order is correct
• English? 1000s words ? arrangement of 26 letters
• DNA Code ? sequence of 3 bases (A,T,G,C) ?
  genetic alphabet
• Start Codon 1, Stop Codons 3

10
The Triplet Code
11
(No Transcript)