PROTEIN SYNTHESIS — TRANSCRIPTION AND TRANSLATION
DNA is the molecule that stores the genetic information in your cells. That information is coded
in the four bases of DNA: C (cytosine), G (guanine), A (adenine), and T
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PROTEIN SYNTHESIS — TRANSCRIPTION AND TRANSLATION
DNA is the molecule that stores the genetic information in your cells. That information is coded
in the four bases of DNA: C (cytosine), G (guanine), A (adenine), and T (thymine). The DNA
directs the functions of the cell on a daily basis and will also be used to pass on the genetic
information to the next generation. Because of its critical role in all the functions of the cell, DNA
is kept protected in the nucleus of your cells.
DNA is organized in sections called genes. Genes code for proteins, and it is proteins that do
all the work in the cell. They function as structural proteins — serving as the building blocks of
cells and bodies. And they function as enzymes — directing all the chemical reactions in living
organisms.
Proteins are made in the cytoplasm by ribosomes. Since DNA cannot leave the nucleus, the
information from DNA must be transmitted from the nucleus to the cytoplasm. During
transcription, each gene on the DNA is read and codes directly for a messenger RNA
(mRNA) molecule. The mRNA is made by matching its complementary bases — C, G, A, and
U (uracil) — to the DNA bases. This process is called transcription, because the message is
going from one version of nucleic acid language (DNA code) to another version of nucleic acid
language (RNA code), so it is like transcribing from the key of G to the key of C in music. This
mRNA transcript then leaves the nucleus and carries the code for making the protein from the
DNA gene in the nucleus to the ribosome in the cytoplasm.
During translation, the ribosome reads the sequence of bases on the mRNA in sets of three —
the triplet codons. Another type of RNA — transfer RNA (tRNA) — brings the protein building
blocks — amino acids — to the ribosome as they are needed. The ribosome bonds the amino
acids together to build the protein coded for by the gene back in the nucleus. This process is
called translation, because the message is going from nucleic acid language (DNA/RNA code)
to the completely different amino acid language (protein code), so it is like translating from
English to Chinese.
PROCEDURE
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