The genetic code is a set of rules that translates nucleotide sequences into proteins, consisting of 64 codons that correspond to 20 amino acids. It features characteristics like being triplet-based, degenerate, and universal, facilitating processes like gene expression and protein synthesis. Applications of the genetic code span various fields, including biotechnology, agriculture, medicine, and forensic science, highlighting its significance in understanding life and advancing human health.

1. GENETIC CODE
Submitted By:-
SATHISH.K
2022002160

2. What is Genetic code???
• Genetic code is a dictionary that corresponds
with sequence of nucleotides and sequence of
amino acids.
• Genetic code is a set of rules by which
information encoded in genetic material(DNA
or RNA sequences) is translated into proteins
by living cells.
• Term given By ″ Goerge Gamow ʺ

3. DISCOVERY
• To understand how proteins are
encoded began after the structure
of DNA was discovered by James
Watson and Francis Crick.
James Watson & Crick
• George Gamow postulated that a
three-letter code must be employed to
encode the 20 standard amino acids
used by living cells to build proteins.

4. Introduction of genetic code
• The letters A,G,T and C correspond to the
nucleotides found in DNA. They are organized into
codon.
• The collection of codons is called Genetics code.
• For 20 amino acids there should be 20 codons.
• Each codon should have 3 nucleotides to impart
specificity to each of the amino acid for a specific
codon.
1 nucleotide – 4 combinations
2 nucleotide-16 combinations
3nucleotide- 64 combinations( most suited for 20 amino
acids)

6. Genetic code can be expressed
in a simple table with 64 entries

7. Codon and its type
• Genetic code is a Dictionary consists of
“Genetic words” called CODONS.
• Each codon consists of three bases (triplet)
• There are 64 codons.
• 61 codons code for 20 amino acids found in
protein.
• 3 codons do not code for any amino acid.

8. Type of codon
 Sense Codons
 Signal Codons
• Start codons
• Stop codons
 Sense codon:- The codon that code for amino
acid are called sense codon.
 Signal codon:- Those codons that code for
signal during protein synthesis
are called signal codons.
For Example:- AUG, UAA, UAG &
UGA

9. conti…..
“Terminating Codons”
UAA, UAG & UGA are termination codons or
nonsense codons & are often referred to as amber, ochre
& opal codons.
“Initiating codon”
AUG is the initiation codon. It codes for the first amino
acid in all proteins.
At the starting point it codes for methionine in
eukaryotes & formyl methionine in prokaryotes.

10. ANTICODON
• The base sequence of t RNA which pairs with
codon of mRNA during translation is called
anticodon.

11. Characteristic of the genetic code
1. Triplet code
2. Comma less
3. Nonoverlapping code
4. The coding dictionary
5. Degenerate code
6. Universality of code
7. Non ambiguous code
8. Chain inition code
9. Chain termination codons

12. “Genetic code is triplet”
• The genetic code is triplet. There are 64 codons.

13. “Universality”
• The genetic code is universal.
• AUG is the codon for methionine in mitochondria. The
same codon (AUG) codes for isoleucine in cytoplasm.
With some exceptions noted the genetic code is universal.
“ Non-Ambiguous”
• The genetic code is non-ambiguous.
• Thus one codon can not specify more than one amino
acid.

14. “Non-overlapping”
• One base cannot participate in the formation of more than
one codon.
• This means that the code is non-overlapping.
“Continuous Translation”
• The gene is transcribed & translated continuously from a
fixed starting point to a fixed stop point.
• Punctuations are not present between the codons.

15. “The code has polarity”
• The code has a definite direction for reading of message
which is referred to as polarity.
• Reading of message from left to right & right to left will
specify for different amino acids.
• For Example UUG stands for leucine, & from right to left it
is GUU which stands for valine.

16. Degeneracy of genetic code
• An amino acid can be coded for by more than one
codon. This is called degeneracy of genetic code.

17. Wobble hypothesis
• Crick postulated the ‘wobble hypothesis’ to
account for the degeneracy of genetic code.
According this hypothesis, the first two bases of a
codon pair according to the normal base pairing
rules with the last two bases of the anticodon.
Base-pairing at the third position of a codon is
wobble

18. Wobble hypothesis explains
degeneracy
• Wobble hypothesis explains the
degeneracy of the genetic code, i.e,
existence of multiple codons for a single
amino acid. Although there are 61 codons
for amino acids, the number of tRNA is
far less (around 40)which is due to
wobbling.

19. CLINIC SIGNIFICANCE
• Mutation can be well explained using the genetic
code.
• A) Point Mutations
1) Silent
2) Misense
3) Nonsense
• B) Frame shift mutations

20. APPLICATIONS
Genetic code applications are numerous and
diverse, transforming various fields
Biotechnology
1. Genetic engineering 2. Gene therapy
3.Biopharmaceuticals
Agriculture
1. Crop improvement 2. Plant breeding.
3. Precision agriculture

21. Medicine
1. Genetic testing 2. Personalizedmedicine.
3. Gene editing
Forensic Science
1. DNA fingerprinting 2. Paternity testing.
3. Genetic profiling
Others
Conservation biology,Synthetic
Biology,Pharmaceuticals,Data Analysis and
Computing

22. Conclusion
• The genetic code is a remarkable, complex
system underlying life’s diversity. Continued
research and innovation will unlock new
applications, transforming our understanding
of life and improving human well-being