DNA: The Blueprint of Life
* DNA (deoxyribonucleic acid) is a long molecule that contains the genetic instructions for building and maintaining an organism.
* It's structured like a twisted ladder, with two strands of nucleotides (adenine, guanine, cytosine, and thymine) linked together.
* The order of these nucleotides forms a code that carries the genetic information.
Genes: The Building Blocks of Traits
* Genes are segments of DNA that contain the code for specific proteins.
* Proteins are the workhorses of the cell, carrying out a vast array of functions, from building structures to catalyzing chemical reactions.
* The specific sequence of nucleotides within a gene determines the sequence of amino acids in the corresponding protein.
From Gene to Protein: The Central Dogma
1. Transcription: The DNA sequence of a gene is copied into a messenger RNA (mRNA) molecule.
2. Translation: The mRNA molecule travels to ribosomes, where it's used as a template to assemble amino acids into a protein.
How Genes Influence Traits
* Proteins determine traits: The proteins produced from genes influence various characteristics, such as eye color, height, and even susceptibility to certain diseases.
* Variations in genes: Different versions of a gene, called alleles, can lead to variations in traits.
* Environmental influences: The environment can also influence how genes are expressed, leading to variations in traits even among individuals with identical genes.
Example:
* Eye Color: A gene called OCA2 influences eye color. Different alleles of this gene can lead to brown, blue, green, or other eye colors.
Key Points:
* Genes are specific segments of DNA that code for proteins.
* The sequence of nucleotides within a gene determines the sequence of amino acids in a protein.
* Proteins are responsible for a wide range of functions that contribute to an organism's traits.
* Variations in genes and environmental influences can lead to variations in traits.
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