Answer:
codon, AUG, RNA
Step-by-step explanation:
The cause and effect relationship between the genetic code and gene expression is a fundamental aspect of how DNA controls the production of proteins in a cell. The genetic code, which is carried by the DNA molecule, determines the sequence of amino acids in a protein. Gene expression refers to the process by which the information encoded in a gene is used to synthesize a protein.
The genetic code consists of a sequence of nucleotides (A, T, C, and G) in DNA. Each set of three nucleotides, known as a codon, corresponds to a specific amino acid. For example, the codon "AUG" codes for the amino acid methionine. The genetic code is universal, meaning that the same codons code for the same amino acids in all living organisms.
The process of gene expression involves several steps. First, the DNA double helix is unwound, and the gene of interest is transcribed into a molecule called messenger RNA (mRNA). This process, known as transcription, occurs in the nucleus of the cell. The mRNA then leaves the nucleus and enters the cytoplasm.
Next, the mRNA is translated into a protein through a process called translation. Ribosomes, which are cellular structures, read the codons on the mRNA and link the corresponding amino acids together to form a protein chain. The sequence of amino acids in the protein determines its structure and function.
Mechanisms of gene regulation control when and to what extent a gene is expressed. These mechanisms ensure that the right genes are expressed in the right cells at the right time. Gene regulation can occur at various levels, including transcription, RNA processing, translation, and protein modification. For example, transcription factors are proteins that bind to specific DNA sequences and either activate or repress gene expression.
DNA segments that do not code for proteins also play important roles in gene regulation and other cellular processes. These non-coding regions, often referred to as "junk DNA" in the past, are now known to have regulatory functions. For instance, they can act as enhancers or silencers of gene expression. Additionally, non-coding DNA contains repetitive elements, such as telomeres and centromeres, which are essential for chromosome stability and cell division.
In summary, the genetic code determines the sequence of amino acids in a protein, and gene expression involves the transcription and translation of the genetic information. Mechanisms of gene regulation control when and how genes are expressed. Non-coding DNA segments have regulatory functions and contribute to chromosome stability and cell division.