1. Central Dogma of Biology
From DNA to Protein
Overview:
DNA---------------------> RNA--------------------> Protein
transcription translation
Genes code for proteins

2. RNA
• RNA is a nucleic acid.
• Different than DNA in three ways.
1. RNA is single stranded
2. Sugar in RNA is ribose
3. RNA does not contain nitrogenous base
thymine but instead contains nitrogenous
base uracil (U)

3. RNA
• Three types of RNA
1. messenger RNA (mRNA)
Brings the instructions from the nucleus to the
cytoplasm to make proteins
2) . ribosomal RNA (rRNA)
Binds to the mRNA and uses the instructions to
bind amino acids to make a protein.
3. transfer RNA (tRNA) delivers amino acids to
the ribosome to be assembled into a protein.

4. How proteins are made
• Transcription
Enzymes make an RNA copy of a portion of
a DNA strand in the process called
transcription.
*DNA To RNA (mRNA)
Everything from DNA is copied but not all is
needed.

5. How proteins are made
• RNA Processing
Not all the nucleotides in the DNA of eukaryotic
cells carry instructions or code for making proteins.
Long noncoding nucleotide sequences are called
introns.
Coding nucleotide sequences are called exons.
When mRNA is transcribed from DNA both introns
and exons are copied. The segments of introns on
mRNA are removed and only the exons are put back
together and the new mRNA leaves the nucleus and
travels to the ribosome.

7. The Genetic Code
The strand of mRNA transcribed from DNA acts
as a genetic message ( the complete information
for building of a protein)
The message on mRNA is broken into sections of
three nitrogenous bases called a codon. Each
codon codes for one amino acid.
Ex. UUU results in the amino acid phenylalanine
being placed in a protein.

8. The genetic code
There are a total of 64 possible combination
sequence of three bases. Not all code for a
protein.
Codon AUG is a start codon
Condon UAA is the stop codon indicating that
the protein chain ends at that point.

10. Translation: From mRNA to Protein
Translation is the process of converting the
information in a sequence of nitrogenous bases
in mRNA.
Translation takes place at the ribosome in the
cytoplasm.

11. • The role of transfer RNA (tRNA)
• Each tRNA molecule attaches to only on type
of amino acid.

12. Translation: From mRNA to Protein
The tRNA has a section that is called the anticodon.
The anticodon on the tRNA pairs up with the codon
on the mRNA. The tRNA has a specific amino acid.
Another tRNA with the anticodon for the next
codon comes and then the two amino acids bonded
together by a peptide bond. The amino acids breaks
free from the tRNA and the process continues and
the protein gets larger and stops until it reaches a
stop codon.

13. Translation: mRNA to Protein
• The amino acids fold, twist into a 3D structure and then you have a
protein.