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What is DNA?

  • DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA.
  • Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).
  • The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
  • The order, or sequence, of these bases determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences.
  • DNA bases pair up with each other, A with T and C with G, to form units called base pairs.
  • Each base is also attached to a sugar molecule and a phosphate molecule. Together, a base, sugar, and phosphate are called a nucleotide.

Mitochondrial DNA


  • Mitochondria are structures within cells that convert the energy from food into a form that cells can use.
  • Each cell contains hundreds to thousands of mitochondria, which are located in the fluid that surrounds the nucleus.
  • Mitochondria produce energy through a process called oxidative phosphorylation. This process uses oxygen and simple sugars to create adenosine triphosphate (ATP), the cell’s main energy source.
  • Mitochondrial DNA contains 37 genes, all of which are essential for normal mitochondrial function.
  • Thirteen of these genes provide instructions for making enzymes involved in oxidative phosphorylation.
  • The remaining genes provide instructions for making molecules called transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs), which are chemical cousins of DNA.

Mummification


  • Mummification is a process in which the skin and flesh of a corpse can be preserved.
  • The process can occur either naturally, or it can be intentional.
  • If it occurs naturally, it is the result of cold (as can be found in a glacier), acid (as can be found in a bog) or dryness.
  • The practice was widely practiced in ancient Egypt.
  • Processes used for mummification were:-
    • Mummification involved the removal of the bulk of the internal organs as well as moisture from the body.
    • The body cavity was then soaked in a bath of natron which acted as a dehydrating agent. Natron is comprised of sodium bicarbonate and sodium carbonate.
    • Once dried, the body was rid of all temporary stuffing and filled with permanent stuffing. The slit in the abdomen was closed off, and wax or resin was used to seal off the nostrils.
    • The warm resin was poured into the form before wrapping was resumed.
    • Hundreds of yards of linen were employed to wrap the corpse effectively.

Once complete, the mummy was placed in the coffin in preparation for the burial rites.

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