Question

What name is applied to the specific section of the DNA molecule that contains the code for construction of a particular protein?

Short answer

A gene is the specific section of the DNA molecule that contains the code for constructing a particular protein, acting as a blueprint for protein synthesis by specifying the order of amino acids.

Step-by-step solution

Definition

The section of the DNA molecule that contains the code for constructing a particular protein is called a "gene."

Role of genes in protein synthesis

In the process of protein synthesis, genes act as a blueprint for creating proteins. They provide the necessary information to build a protein by specifying the order of amino acids, which are the building blocks of proteins. This information is transcribed from the DNA into messenger RNA (mRNA), which is then translated into amino acids and assembled into a protein by ribosomes. In summary, a gene is the specific section of the DNA molecule that contains the code for constructing a particular protein. Its role in protein synthesis is to provide the necessary information for building the amino acid sequence in the protein.

Key concepts

DNA

Often referred to as the blueprint of life, deoxyribonucleic acid (DNA) is a molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses. Structurally, DNA is a long molecule made up of units called nucleotides, which are arranged in a double-helix formation. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base. The sequence of these bases (adenine [A], thymine [T], guanine [G], and cytosine [C]) encodes the genetic information.

Within the DNA molecule, specific sections known as genes are the most critical elements for heredity and variation in traits. Genes are segments of DNA that constitute specific instructions for making proteins. Whenever a cell needs to produce a particular protein, it activates the corresponding gene and begins the process of protein synthesis, which is crucial for cellular functions and the organism's overall development.

Protein Synthesis

Protein synthesis is a two-step process within a cell that allows it to express genes by building proteins. The first step is called transcription, where the information in a gene's DNA is transferred to a messenger RNA (mRNA) molecule. During this stage, enzymes like RNA polymerase create a single-stranded RNA copy of the gene's DNA sequence, which serves as a template for protein production. This mRNA carries the code from the nucleus to the cytoplasm, where the second step, translation, occurs.

During translation, the mRNA works with a ribosome and transfer RNA (tRNA) molecules to synthesize proteins. The ribosome reads the mRNA sequence three bases at a time, known as codons, and each codon codes for one amino acid, the building block of proteins. As the ribosome progresses along the mRNA, tRNA molecules bring the appropriate amino acids that match the current codon being read. This process continues, linking amino acids together in the precise sequence dictated by the mRNA, until a complete protein is formed. The specific sequence of amino acids determines the structure and function of the protein.

Amino Acids

Amino acids are organic compounds that serve as the building blocks of proteins. There are 20 different amino acids commonly found in proteins, each with a central carbon atom, an amino group, a carboxyl group, and a variable side chain or R-group, which gives each amino acid its unique properties.

Different amino acids are assembled in a linear chain to form a protein. The sequence of amino acids in a protein is specified by the sequence of codons in the mRNA, which, in turn, is transcribed from the DNA within genes. This sequence is critically important: even a change in just one amino acid can significantly affect a protein's structure and function. After amino acids are linked together by peptide bonds during translation, the resulting polypeptide chain folds into a complex three-dimensional shape, which is essential for its role in cellular processes. Understanding the nature and variety of amino acids is vital for comprehending how proteins carry out their diverse functions in living organisms.