Imagine that you have created a very short polypeptide from the following RNA sequence: GACGAAGGAGAG. a. What is the amino acid sequence of the polypeptide? b. What property does the polypeptide have?

Understanding how polypeptides are synthesized begins with deciphering the RNA sequence. In the world of genetics, RNA serves as a crucial intermediary between DNA and proteins. The RNA sequence in question, GACGAAGGAGAG, represents a specific segment of messenger RNA (mRNA) that is read by cellular machinery to translate genetic information into proteins.

Ribonucleic acid (RNA) is a polymer comprising four different nucleotides: adenine (A), cytosine (C), guanine (G), and uracil (U). In RNA sequences, these nucleotides are arranged in a specific order to convey genetic instructions. During protein synthesis, or translation, the mRNA is read in sets of three nucleotides known as codons. Each codon specifies a particular amino acid, which are the building blocks of proteins. Because the genetic information is tripartite, every three letters (nucleotides) represent a word or codon in the language of proteins.

The genetic code is a set of rules that defines how the sequence of nucleotides in an RNA strand is converted into an amino acid sequence in a protein. It's essentially the cell's 'Rosetta Stone' for translating the language of genetics into the language of proteins. The genetic code is universal, which means it is nearly the same across all organisms, from bacteria to humans.

Each group of three nucleotides, or codon, corresponds to one of the twenty standard amino acids or to a signal to start or stop protein synthesis. For instance, the RNA codons GAC and GAA code for the amino acids Aspartic acid and Glutamic acid, respectively. This relationship between codons and amino acids is crucial to understanding how proteins are built. The process of reading mRNA and assembling amino acids in the correct order is known as translation, which occurs within a ribosome in the cell. Thanks to the genetic code, cells can faithfully translate genetic instructions into the vast array of proteins that perform various functions within living organisms.

The amino acid sequence is the final output of translating an RNA sequence and it defines the primary structure of a protein. Amino acids, linked together by peptide bonds in a specific order dictated by the mRNA template, comprise the polypeptide chain. In our exercise, the RNA sequence GACGAAGGAGAG translates into the amino acid sequence of Aspartic acid, Glutamic acid, Glycine, and Glutamic acid. This sequence determines how the polypeptide will fold and what properties it will have.

For example, certain amino acids like Aspartic acid and Glutamic acid are acidic, which can give the polypeptide an overall acidic property. This can affect where the polypeptide operates optimally within the body since different parts of the body have different pH levels. Additionally, amino acid sequences are responsible for the formation of the complex three-dimensional structures of proteins, ultimately determining their function. Each protein's unique structure allows it to perform a specific role, from speeding up chemical reactions as enzymes to acting as building blocks for tissues.