Organisms like bacteria are prokaryotic cells. The final products are the structures that we call chromosomes. There are several different stages of packaging. A small amount of DNA is also in organelles called mitochondria, which are the cell’s powerhouses.īecause there’s a limited amount of space within the nucleus, the body condenses the DNA into packages. In a eukaryotic cell, DNA is within the nucleus. This means that their cells have a membrane-bound nucleus and several other membrane-bound structures called organelles. Humans and many other organisms have eukaryotic cells. The exact location of it depends on the type of cell. Some lifestyle factors such as obesity, exposure to cigarette smoke, and psychological stress can also contribute to telomere shortening.ĭNA is present in our cells. Studies associate telomere shortening with the aging process. They help protect DNA from damage, but they also shorten with each round of DNA replication. Telomeres are stretches of repetitive DNA sequences at the ends of your chromosomes. After we’ve passed our peak reproductive years, the repair process naturally declines.Īnother part of DNA that may be involved in aging is telomeres. It’s thought that DNA damage is repaired more faithfully when we’re of reproductive age and having children. One theory as to why DNA damage accumulates as we age concerns evolution. However, this one mechanism of damage may not be sufficient to explain the aging process. Something that may play a large role in the DNA damage associated with aging is damage due to free radicals. Unrepaired DNA damage can accumulate as we age, helping to drive the aging process. Examples of some polymorphisms are hair and eye color. Some are harmless, while others contribute to our diversity as a species.Ĭhanges that occur in at least or more than 1 percent of the population are called polymorphisms. Some cancer-causing mutations are heritable, while others develop through exposure to carcinogens like UV radiation, chemicals, or cigarette smoke.īut not all mutations are bad. For example, if genes coding for proteins involved in cellular growth mutate, cells may grow and divide out of control. Mutations can also lead to the development of cancer. Some diseases that occur due to mutations in a single gene include cystic fibrosis and sickle cell anemia. If the protein doesn’t work properly, diseases can develop. Changes in the DNA code can negatively impact how the body produces proteins. Mutations are permanent changes in the DNA sequence. There are at least five major DNA repair pathways. Your cells have specialized proteins that can detect and repair many cases of DNA damage. Damage can occur due to errors in DNA replication, free radicals, and exposure to UV radiation. According to estimates, tens of thousands of DNA damage events occur every day in each of our cells. Scientists are still learning more and more about this “non-coding” DNA. The other 99 percent helps regulate things like when, how, and in what quantity your body produces proteins. Genes make up very little of your genome - only 1 percent. This DNA comes from the sperm and egg, respectively. You inherit one half of your DNA from your father and one half from your mother. It contains roughly 3 billion bases, 20,000 genes, and 23 pairs of chromosomes. The complete set of your DNA is called your genome. In the second step, specialized components of the cell read the mRNA’s message three base pairs at a time and work to assemble a protein, amino acid by amino acid. It travels outside the nucleus, serving as a message to the cellular machinery that builds proteins. This process creates the messenger molecule RNA (mRNA). Then, special proteins within the nucleus read the base pairs on a DNA strand to create an intermediate messenger molecule. How do you get from the DNA code to a protein?įirst, the two DNA strands split apart. When placed together in the correct order, each protein has a unique structure and function within your body. Proteins contain different combinations of amino acids. This tells the cell not to add more amino acids to the protein. Some combinations, like T-A-A, T-A-G, and T-G-A, also indicate the end of a protein sequence. For example, the base pairs T-G-G specify the amino acid tryptophan, while the base pairs G-G-C specify the amino acid glycine. The DNA sequence that houses the information to make a protein is called a gene.Įach group of three bases corresponds to specific amino acids, which are the building blocks of proteins. Your cells read this code three bases at a time to generate proteins that are essential for growth and survival. These instructions exist within the sequence of nucleotide base pairs. DNA contains the instructions that are necessary for an organism to grow, develop, and reproduce.
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