Question
37. Explain the process of protein synthesis using models of DNA and RNA. Include the roles transcription and translation in this process , and how they relate to gene expression.
Answer
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Quilla
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Answer
Protein synthesis begins with the process of transcription where information from the DNA is transcribed into a messenger RNA (mRNA). The mRNA exits the nucleus and moves towards the ribosomes in the cytoplasm where the translation phase initiates. The ribosomes pull the mRNA strand, reading it codon by codon, as specific depleting Transfer RNA(tRNA) arranges proper amino acid based on these codons to form an augmenting protein chain. This two-step process of transcription (DNA to RNA) and translation (RNA to protein) embody gene expression, as genetic instructions in DNA are eventually used to create functional, discrete proteins that carry out numerous tasks within cells.
Explanation
1. **The Process of Protein Synthesis**: Protein synthesis is the process by which DNA directs the production of proteins. It consists of two key phases, namely transcription and translation.2. **Transcription**: It involves the conversion of information from DNA code into an intermediary called mRNA (messenger RNA). DNA is unzipped by the enzyme known as RNA polymerase, then exposed nucleotide bases on one side of the DNA strand serve as a template on which bases pair up to form an mRNA stranscript. The specific base pairing rules in RNA are that Adenine (A) pairs with Uracil(U, as RNA replaces the Thymine of DNA in base pairing with Adenine), Cytocine (C) pairs with Guanine(G). This process constructs a strand of mRNA that holds a mirror-image copy of the gene. 3. **Translation**: It is the process of converting the coded mRNA information into a sequence of amino acids that makes up a new protein. The mRNA, heads from the nucleus into the cytoplasm of the cell where it is recognised by ribosomes - which act as protein-constructing machines. The ribosome attaches to one end of the mRNA strand, and pulls the mRNA strand through like a ticker tape, reading it one codon at a time. Each codon carries instructions of a specific amino acid to add to the growing protein chain. These codons are recognised by transfer RNA (tRNA) which carry the appropriate amino acid to the ribosome. Here, anticodons on the tRNA molecules pair with complimentary codons found on the mRNA strand, sequentially adding amino acids to the growing protein sequence.4. **Relation to gene expression**: Successively, gene expression refers to the process of synthesizing proteins based on the information encoded in a gene. During this, the gene's DNA sequence is first transcribed into mRNA, which is then translated into proteins. Collectively, this two-step process, transcription and translation, called gene expression, determines how genes exert their influence in a cell, shaping the specifics of cellular functions.