Biology Of The Human Body Essay

1750 Words Jun 28th, 2015 7 Pages
All living things are comprised of cells, the basic units of life. Some organisms have only one cell.6 The human body, however, has more than ten trillion cells.6 In plants and animals, cells perform specific functions.6 One example of this is neurological cells transmitting information in the brain.6 Specialized cells group together to form tissues which then form organs.6
Although cells do different jobs, all cells share common features.6. All cells are alive, they reproduce, and they die.6 A thin cover, called the cell wall, encloses each cell.6 Tiny structures are embedded in a jelly-like substance within the cell.6 One of these structures is the nucleus.6 The nucleus contains the cell 's genetic program, a master plan that controls almost everything the cell does.6 The nucleus contains two kinds of structures - chromosomes and nucleoli.6 Chromosomes are threadlike structures that are made of a chemical substance called DNA (deoxyribonucleic acid) and certain proteins.6 Nucleoli are round bodies that form in certain regions of specific chromosomes.6
Every new cell is produced from an existing cell by cellular division.6 When a cell divides, each of the two new cells receives a copy of the genetic program.6 The genetic program carried in DNA acts as a blueprint for life.2 That is why we call DNA the code of life.6 DNA tells cells how to produce exact copies of themselves, and those new cells in turn repeat the process.6
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