Compenduim Review Unit 1 Topic 1: Cells

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Cell Structure and Function:

The cell is the structural and functional unit of all living organisms, and is sometimes called the "building block of life."[1] Some organisms, such as bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram.) The largest known cell is an ostrich egg. http://www.answers.com/topic/cell

Each cell is somewhat self contained and self maintaining, it takes nutrients and turns it into energy, carries out special functions and reproduces as necessary.

There are two types of cells the eukaryotic and the prokaryotic cells:


Prokaryotic cells are single cells that lack a membrane-bound nucleus. Their genetic information is in a circular loop called a plasmid. They have very few distinguishable features inside when looked at under a microscope. They have three main shapes: rod, spherical and spiral. They divide by bionary fisson.


Eurokaryotic cells are approximately 10 times the size of a prokaryotic cell and can be up to a 1000 times greater in volume. They are mostly multi-cellular and contain membrane-bound organelles such as mitochondria and chloroplasts.