Changes

Small parts of DNA called genes serve as the instructions for the body to carry out its functions and give rise to traits such as eye color, hair color, etc. Genes are packaged into [[chromosomes]]. Each individual human being has 23 pairs of chromosomes, where one set is inherited from his/her mother and the other set is inherited from his/her father.

Small parts of DNA called genes serve as the instructions for the body to carry out its functions and give rise to traits such as eye color, hair color, etc. Genes are packaged into [[chromosomes]]. Each individual human being has 23 pairs of chromosomes, where one set is inherited from his/her mother and the other set is inherited from his/her father.

[[Prokaryotic DNA]] is circular (a closed loop), while [[Eukaryotic DNA]] is linear (with ends). DNA in [[prokaryote]]s usually consists only of one closed loop chromosome.<ref>Campbell, Neil A, et. al. ''Biology''. 6th ed. San Francisco: Benjamin Cummings, 2002. 299, 530-31.</ref>

[[Prokaryotic DNA]] is circular (a closed loop), while [[Eukaryotic DNA]] is linear (with ends) with the exception of [[Mitochondrial DNA]], which is circular too. DNA in [[prokaryote]]s usually consists only of one closed loop chromosome.<ref>Campbell, Neil A, et. al. ''Biology''. 6th ed. San Francisco: Benjamin Cummings, 2002. 299, 530-31.</ref>

DNA changes account for differences between individuals. However, they can also cause medical problems.

DNA changes account for differences between individuals. However, they can also cause medical problems.