DNA Function and Aging
Yeshiva Ohr Yisrael
All living organisms consist of cells. Cells contain mainly internal structures and are highly complex. There are three main types of cells: archaea, prokaryotes, and eukaryotes. Prokaryotes are single celled, archaea are organisms often found in extreme environmental condition, and eukaryotes are multi-cellular organisms which include humans and animals ("Cells - Structure and Function," n.d.). While all types of cells contain deoxyribonucleic acid, I will be focusing specifically on types of damage and repair in eukaryotic cells as this applies to aging in humans, as well as different options to slow and prevent aging at it’s current rate.
DNA, or deoxyribonucleic acid, is a molecule found in every eukaryotic cell. DNA provides instructions to build proteins. These proteins allow living organisms to live, grow, and develop. The mitochondria and nucleus house the DNA for eukaryotic cells. The nucleus is one of the most important parts of a eukaryotic cell. It contains DNA which stores and gives instructions on how cells should reproduce. During reproduction, nuclear DNA, or DNA found in the nucleus, is obtained from the male and female equally (National Institute of Health, 2014). Mitochondria are another very important feature found in cells. Mitochondria are responsible for many cellular activities, but probably the most important is being able to convert energy from food into usable energy for the body (Newcastle University, n.d.). DNA located in the mitochondria is only passed on from the female.
Nucleotides make up DNA sequences. Each nucleotide contains a phosphate group, a sugar group, and a nitrogen base. The nitrogen bases are adenine, thymine, guanine, or cytosine. Nitrogen bases pair together to form a double helix structure. Adenine pairs with thymine, and guanine pairs with cytosine which joins two DNA strands and then coils around. These four nitrogen bases make up the different traits that are expressed in organisms. For example, hair color and eye color are determined based on a person’s inherited DNA sequence. The nitrogen bases form a unique code, or sequence, based on the order that they are in and how they are paired. When these nitrogen bases form a code to produce a protein, it is called a gene. Genes make up very little of a DNA sequence. Most of the DNA sequence is composed of other instructions on how to produce the protein. Proteins are formed by amino acids, mRNA (messenger ribonucleic acid), and amino acids. Enzymes read the instructions for the protein carried in the DNA and transcribe the information to mRNA. The mRNA translates the DNA coding so that it is readable by amino acids. The instructions then link the amino acids in the appropriate form so that they form the protein (National Institute of Health, 2014).
DNA strands are constantly being damaged in the human body due to the body’s ageing and not being able to repair itself as efficiently and many environmental conditions such as UV rays and radiation. These kinds of factors can results in a double break in a DNA strand. DNA damage is normal and usually not harmful to the body. The body has built in mechanisms which can normally repair damaged DNA so that it is not replicated and spread to other parts of the body. Before a cell reproduces, it first checks the DNA to make sure that it is not damaged. If the DNA is damaged, the cell will attempt to repair the DNA (Negritto, 2010).
DNA can repair itself in many ways including Base Excision Repair, Nucleotide Excision Repair, and Double-Strand Break Repair. Base Excision Repair (BER) is when a single nucleotide base pair is removed and replaced by the use of enzymes. Enzymes are proteins that are found in the body that are used to speed up chemical reactions. This type of repair is used mainly for DNA that is damaged from oxidization or hydrolysis and has only a single break. BER leaves almost no...
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