DNA Structure And Structure: DNA Structure And Function

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1. DNA Structure and Function

DNA is the type of organic compound that stores the genetic information in a living organism. DNA is made up of two strands of nucleotides, which include a phosphate group, five carbon sugar, and a nitrogenous base. Each individual strand in held together by strong covalent bonds (a bond formed as a result of the distribution of electrons between atoms). The two strands are then joined to each other by hydrogen bonds between complementary bases. There are four nitrogenous bases: adenine, thymine, cytosine, and guanine. Adenine is complementary to thymine while guanine is complementary to cytosine.

Role of Hydrogen bonds

Hydrogen bonds are produced when a negatively charged atom such as oxygen and a hydrogen
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In this process, helicase (an enzyme used to breakdown the hydrogen bonds between bases that are complementary) separates two DNA strands; both strands are used as a template strand to make complementary strands. The newly created complementary strands are then attached to the original via weak hydrogen bonds. Replication occurs during S-phase (the period in the cell cycle where DNA is synthesized) of Interphase (the period in the cell cycle between cell division) and ensures that each daughter cell created by cell division will have a copy of the DNA. If the DNA fails to separate and can’t replicate during S-phase, the checkpoint mechanism will not allow the cell cycle to continue and meiosis/mitosis and cell division cannot …show more content…
These mechanisms are genetic drift, natural selection, mutations, gene flow, and non-random mating. Mutations involve a permanent change in the DNA sequence of an organism. Mutations can be beneficial, neutral, detrimental, or fatal to organisms. Mutations are passed on from parent to offspring and can cause evolution by increasing the size of the gene pool. Another mechanism of evolution is gene flow. Gene flow takes place when organisms immigrate or emigrate from a population permanently. This can can either increase or decrease in the gene pool as a whole. A third mechanism of evolution is genetic drift in which a random event acts on a small population and decrease the size of the gene pool. The fourth mechanism of evolution is non-random mating. In non-random mating, mates are chosen based on preferential trait or physical appearance. Those preferential traits can then be passed on to the offspring. Natural selection is the fifth major mechanism of evolution. Natural selection works on the organism, allowing for adaptations that give them increased survival and reproductive

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