Nursing School Entrance Exams by Sandra S. Swick

Author:Sandra S. Swick
Language: eng
Format: epub
Publisher: Barrons Educational Series
Published: 2020-05-26T00:00:00+00:00

CELLS—BASIC UNITS OF LIVING MATTER

■ Cell Concepts

○ Living matter is generally organized into units known as cells.

Unicellular organisms are composed of one cell.

Multicellular organisms are composed of numerous, specialized cells.

○ Unit of structure

Cells provide structure and form to an organism.

Cells assume varied shapes and sizes as they become specialized to perform specific duties.

○ Unit of function

Each cell is a living unit, a biological chemical factory.

Each cell provides for repair of tissues, growth, energy, and reproduction.

○ Unit of Growth

All living organisms begin life as a single cell.

Multicellular organisms have a single cell that grows to a certain size and then divides and redivides.

As the number of cells increases, the size of the organism increases.

○ Unit of heredity

Dividing cells produce identical cells.

Cells carry hereditary information that is passed on when cells divide. Hereditary information is passed along from generation to generation.

Information is coded in molecules of DNA.

○ Parts of a cell (see Figure 6.1)

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