Describe that the sequence of bases in a gene determines the sequence of amino acids needed to make a specific protein (knowledge of the details of nucleotide structure is not required)

Sourav PanNovember 4, 2024

Answered

The Relationship Between Gene Sequence and Protein Structure

The sequence of bases in a gene is fundamental to the process of protein synthesis, as it directly determines the sequence of amino acids that will be assembled to form a specific protein. This relationship is crucial for understanding how genetic information translates into functional molecules within living organisms.

Key Concepts

1. Gene Composition
   • A gene is composed of a sequence of nucleotides, each consisting of a base (adenine, thymine, cytosine, or guanine), a sugar molecule, and a phosphate group. The order of these bases along the DNA strand encodes the genetic information.
2. Base Triplets and Codons
   • The genetic code is read in groups of three bases, known as codons. Each codon corresponds to a specific amino acid or serves as a signal for starting or stopping protein synthesis. For example:
     • The codon “AUG” codes for the amino acid methionine and also serves as the start signal for translation.
     • Other codons correspond to different amino acids, such as “UUU” for phenylalanine or “GAA” for glutamic acid.
3. Transcription Process
   • During transcription, the DNA sequence of a gene is transcribed into messenger RNA (mRNA). This mRNA strand is complementary to the DNA template and carries the same information but in RNA form. For example:
     • If the DNA sequence is “ATG-CGT-TTA,” the corresponding mRNA sequence would be “AUG-CGA-AAU.”
4. Translation Process
   • Once the mRNA is synthesized, it moves to the ribosome in the cytoplasm, where translation occurs. During translation:
     • The ribosome reads the mRNA codons sequentially.
     • Transfer RNA (tRNA) molecules bring specific amino acids corresponding to each codon.
     • The ribosome links these amino acids together in the order specified by the mRNA to form a polypeptide chain.
5. Protein Folding and Function
   • After translation, the polypeptide chain undergoes folding and modifications to achieve its final three-dimensional structure. The specific sequence of amino acids determines how the protein will fold and function. This structure is critical for the protein’s role in biological processes.