From DNA to Protein California Standards: 1.d, 5.a, b

Central Dogma of Molecular Biology Dogma: something held as an established opinion; especially : a definite authoritative tenet. b : a point of view or tenet put forth as authoritative without adequate grounds Tenet: a principle, belief, or doctrine generally held to be true; especially : one held in common by members of an organization, movement, or profession

From DNA to Protein

Central Dogma of Molecular Biology The Central Dogma of Molecular biology states that the information found in deoxyribose nuclear acid (DNA) is transferred to ribonucleic acid (RNA) and then to protein molecules. DNA  RNA  Protein

Difference Between DNA & RNA Sugar – deoxyribose Structure – double helix Thymine as nitrogen base Sugar – ribose Structure – single helix Uracil as nitrogen base

Transcription Transcription is taking the information found in DNA and transcribing that information into the nucleic acid messenger RNA (mRNA). Takes place in the nucleus of the eukaryotic cell. Utilizes the enzyme RNA polymerase.

Transcription

RNA Polymerase In Latin poly- means “many”. The suffix –ase indicates an enzyme. Therefore, RNA polymerase is an enzyme that adds many more nitrogen bases to the growing mRNA molecule.

Transcription The information encoded in DNA is transferred onto the molecule mRNA within the nucleus of the cell. Transcribe: to make a written copy of

Transcription The KEY CONCEPT in transcription is the information found on a segment of DNA, called a gene, is converted into a single-stranded RNA molecule.

Translation

Translation This portion of the Central Dogma of Molecular Biology is when the language of nucleic acids is translated into the language of protein. Hence, the term “translation”. Converting one “language” of nucleic acids into a second “language” of protein.

The information from DNA is carried out of the nucleus into the cytoplasm by mRNA. Messenger RNA (mRNA) then goes to a ribosome in the cytoplasm where the protein molecule is made.

DNA chromatin in the nucleus

Translation The information on the DNA molecule is transferred to mRNA. Instead of the nitrogen base, thymine associated with DNA the nitrogen base uracil is substituded for this base on the mRNA molecule. So, there is no thymine in RNA, only uracil.

Translation

Nitrogen Bases (N-bases) The nitrogen bases in DNA are adenine, cytosine, guanine, and thymine. The nitrogen bases in RNA are adenine, cytosine, guanine, and uracil. The nitrogen base thymine (T) in DNA is replaced by uracil (U) in RNA.

DNA: A C G T RNA: A C G U Complementary bases in RNA: A  U C  G

DNA bases: T – A – G – C – T – A – C – T – G - C mRNA bases: A – U – C – G – A – U – G – A – G – G Inside Nucleus Outside Nucleus mRNA bases: A – U – C – G – A – U – G – A – G – G

Translation Once the mRNA is outside the nucleus the process of translation takes place. This process takes place at the ribosome. Remember, ribosomes are the organelles where proteins synthesis takes place. Proteins are made up of amino acids.

Thus the information contained in the mRNA is translated into proteins using a three letter code, called a codon, for a specific amino acid. This codon is made up of three nitrogen bases on the mRNA molecule. The Genetic Code, using this three letter code, is used to determine the specific amino acid.

Codon or nitrogen bases in mRNA: C – A – U Amino Acid: histidine

Transfer RNA (tRNA) The second type of RNA is transfer RNA. Transfer RNA (tRNA) brings a specific amino acid to a specific ribosome. The tRNA’s code for this specific amino acid is called an anticodon. ( t for transfer RNA). A codon matches up to a specific anticodon to form a polypeptide or protein molecule.

Summary: Transcription: DNA into mRNA Translation: mRNA into polypeptide or protein molecule. DNA  mRNA  Protein (polypeptide)

Translation: mRNA Protein ____________________ 2. _____________________ 3. _____________________ 4. _____________________ 5. _____________________

The End