how DNA passes on genetic information?
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DNA is an information medium. You might know that the DNA molecule is shaped like a twisted ladder. The rungs of that ladder are can be made of any of four different chemicals. Those chemicals and more importantly the order they appear in is your genetic code. It’s like letters in a book. Now the DNA molecule is also something like a zipper. The two sides can be unzipped from one another and each is used as a template to build a new strand of DNA. In that way, DNA can be copied to form new cells for growth and reproduction. The next question you might ask is how is that genetic code read to express traits. Your cells contain structures called ribosome that can read RNA ( a molecule like one side of the DNA ladder) and create proteins based on the information they find. Proteins are built like Lego blocks; they can be formed piece by piece by sticking smaller molecules called amino acids together. Each set of three rungs of DNA mean a different amino acid or a special instruction like start building or stop building. So DNA holds information that ribosomes can use to build proteins. How does that determine genetic traits like hair or eye color? The pigments in your hair, eyes, and skin are all proteins. The most common pigment is a brown protein called melanin. Some people have more genes that code for melanin than others and so some people are more darkly colored. Some people have genes that changed or mutated in one of their ancestors and some of their genes no longer code for melanin. They might produce very little pigment and be blond or produce a different pigment like pheomelanine and be red-headed. Now on to the heart of the question. How do parents pass genes to their children, or why do children resemble their parents? Every one of your cells has a full set of DNA organized into structures called chromosomes. Humans have 45 chromosomes in 23 pairs. Why in pairs? Because you get one set from your mother and the other from your father. Usually when your body makes new cells, the entire set of 46 gets copied. However, if your body is making gamete cells, sperm or eggs, those cells only get one half of each pair at random. The two members of each pair can even trade parts so each resulting gamete is highly randomized and completely unique. When an egg cell is fertilized by a sperm cell all the pairs of chromosomes match up and the whole process starts over again
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