1. Transcription and Translation:
* Genes are segments of DNA that contain instructions for building proteins. These instructions are encoded in the sequence of nucleotides (A, T, C, G) within the gene.
* Transcription: The DNA sequence of a gene is copied into a molecule called messenger RNA (mRNA). This mRNA molecule carries the genetic code from the nucleus to the ribosomes in the cytoplasm.
* Translation: The mRNA molecule is read by ribosomes, which use the code to assemble amino acids into a specific protein. The order of amino acids in the protein is determined by the sequence of nucleotides in the mRNA.
2. Protein Function and Trait Expression:
* Proteins are the workhorses of the cell. They perform a wide variety of functions, including:
* Structural components: Proteins provide structure to cells and tissues (e.g., collagen in skin and bone).
* Enzymes: Catalyze chemical reactions in the body.
* Hormones: Act as chemical messengers to regulate bodily functions.
* Antibodies: Part of the immune system, defending against pathogens.
* The function of a protein directly influences a trait. For example, the protein melanin is responsible for skin, hair, and eye color. Variations in the gene for melanin production can lead to different shades of these traits.
In summary: Genes contain instructions for building proteins. These proteins perform various functions that ultimately determine an organism's traits.
