"Central Dogma", a phrase coined by Francis Crick, is used to describe the flow of molecular information through a trio of macromolecules, DNA, RNA and protein. A gene is a nucleotide sequence in DNA to which a specific genetic function can be assigned such as the production of the pigment for eye color. Genes provide the "blueprint" for the production of proteins, Proteins are macromolecules that consist of one or more polypeptides that function as enzymes, hormones, antibodies or structural components of the cell.
So how is information in nucleus-bound DNA expressed as proteins found throughout cells? Through the processes of transcription and translation. The nucleic acid sequence of a gene on the coding strand of DNA is used to create a complementary nucleic acid sequence of messenger RNA (mRNA). Messenger RNA, as the name implies, takes its genetic information or message out of the nucleus and into the cytoplasm of the cell. This transfer of information from DNA to RNA is the process of transcription. Transcription generates a single-stranded mRNA complementary in sequence to the coding or sense strand of DNA, Two other RNA intermediates important to translation and protein synthesis are similarly transcribed from specific gene sequences, ribosomal RNA (rRNA) and transfer RNA (tRNA).
Once outside the nucleus, mRNA takes its genetic message from the nucleus to the ribosomes, the site of translation and protein synthesis.
Translation converts the nucleotide sequence of the mRNA into a specific sequence of amino acids to produce a specific protein. Translation of mRNA is accomplished by translating a series of three (triplet) nucleotides, a triplet of nucleotides is called a codon, into the corresponding amino acid as specified in the Genetic Code (see chart below). The genetic code consists of the three-letter codons present in the nucleotide sequence of mRNA, as read in the 5' -- 3' direction. For example, the first triplet found in all mRNA as transcribed from DNA is composed of the bases, adenine, uracil and guanine (AUG) and translates into methionine (Met), the translation initiator sequence. Without the AUG sequence, translation will not take place.
Objective:
You are "cellular spies". You will be given a "clue" (a segment of DNA), working in pairs, you must transcribe it into mRNA (your strand includes flanking sequences and introns not used in the final mature mRNA), and then move around the room, looking for the correct bead color to translate it into an amino acid sequence.
Codon chart or wheel (use whichever you prefer)
Amino
Acid
|
Pop
Bead color
|
Arginine (Arg)
|
White
|
Cysteine (Cys)
|
Black
|
Lysine (Lys)
|
Red
|
Proline (Pro)
|
Green
|
Tyrosine (Tyr)
|
Yellow
|
Methionine (Met)
|
Blue
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Valine (Val)
|
Purple
|
Phenylalanine (Phe)
|
Orange
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