Problem 12 Each amino acid is specified by ... [FREE SOLUTION] (2025)

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The process of transcription is a vital step in converting the genetic information coded within DNA into a format that can be read and translated into proteins. This is where messenger RNA, or mRNA, comes into play. During transcription, the DNA sequence of a gene is copied into mRNA. This mRNA transcript is essentially a single-stranded copy containing the genetic instructions that will be used to build proteins.
Here's how it works:

• DNA serves as the template, and enzymes called RNA polymerases read this template to synthesize a complementary strand of mRNA.
• The mRNA strand is complementary to the DNA sequence, but instead of thymine (T), it contains uracil (U).
• Once formed, the mRNA transcript leaves the nucleus and travels to the ribosome, where protein synthesis occurs.

mRNA is crucial because it bridges the gap between the DNA in the nucleus and the protein construction sites in the cytoplasm. It's like a "bluprint" that conveys the instructions of the genetic code directly to the areas where proteins are assembled.

The genetic code is often compared to a universal language, conveying information essential for life. It is the set of rules by which the information encoded in mRNA is decoded into proteins. Each three-base sequence on the mRNA, known as a codon, specifies a particular amino acid or a stop signal in protein synthesis.

Key features of the genetic code include:

• It consists of 64 codons representing the 20 amino acids, along with start and stop signals.
• Each amino acid can be encoded by more than one codon, making the code redundant but ensuring that errors (mutations) often don't affect protein formation.
• The code is almost universal across all organisms, meaning the same codon tends to encode the same amino acid in all living beings.
• It is both "unambiguous", as each codon specifies only one amino acid, and "degenerate", since multiple codons can specify the same amino acid.

The genetic code provides the instructions for building proteins, which are crucial for cell structure and function. Without it, cells wouldn't be able to produce the enzymes and structural components necessary for life.

Nucleotide bases are the building blocks of mRNA and indeed all nucleic acids, including DNA. There are four types of nucleotide bases in RNA: adenine (A), uracil (U), cytosine (C), and guanine (G). These bases pair with each other in specific ways to form the rungs of the nucleic acid structure.

Understanding nucleotide bases is vital for grasping how genetic information is encoded:

• In DNA, adenine pairs with thymine (T) and cytosine with guanine. In RNA, uracil replaces thymine.
• The sequence of these bases stores vast amounts of genetic information, and the particular sequence of nucleotides in mRNA will dictate the protein synthesized.
• The order of nucleotide bases in a triplet, or codon, determines which amino acid is added next during protein synthesis.

Nucleotide bases are the letters in the genetic alphabet, forming the words (codons) and sentences that dictate how proteins are made. This makes them fundamental to genetics, molecular biology, and life processes as a whole.