Cell

//This page mentions the differences between plant, animal, and prokaryotic cells. See List of Organelles for a list of organelles inside the cell.//

Cells are the basic "building block" of life. They are the smallest "unit" that all living things share. (This is not to be confused with atom, which makes up both living and nonliving things.) There are two types: prokaryotes (without a nucleus) and eukaryotes (with a nucleus).

=Prokaryotes= Prokaryotes do not have a nucleus, and as such, their DNA floats freely around the cell. They are also usually smaller than eukaryotes, about 0.5 microns. Bacteria are prokaryotes.

=Eukaryotes= Eukaryotes are different from prokaryotes in that they have a nucleus, where their DNA is stored in. There are also other organelles inside the cell that perform certain functions for the cell. There are two types of eukaryotic cells: plant cells and animal cells.

Plant Cells
Plant cells make up plants and vegetation. A typical plant cell is about 30 microns wide. They differ from animal cells in that they have large vacuoles for storage. (note: what about animals?) They also have a tough cell wall surrounding the cell, since they come in contact with fresh water, and need a barrier to stop the cells from bursting (See: osmosis ) Plant cells also contain organelles called chloroplasts, that utilizes sunlight to go through photosynthesis. They also have mitochondria to undergo cellular respiration.

Animal Cells
Animal cells make up animals. (size?) They do not have cell walls, and for the most part do not need them. This is because animal cells are usually found in fluids that have the same concentration as inside the cell. As a result, water does not diffuse into the cell and the cell does not burst (See: osmosis, link above ) Since animal cells do not undergo photosynthesis, they do not contain chloroplasts, only mitochondria for cellular respiration. 