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Basic cell structures review

Key terms

CellBasic unit of living things
OrganelleSpecialized cell structure that performs a specific function

Common cell organelles

OrganelleFunctionFound in all cells?
Cell membraneSupports/protects cell; controls movement of substances into/out of cell; separates cell from its environmentYes
Cell wallStiff, rigid structure that surrounds the cell membrane to support/protect the cellNo
CytoplasmClear, thick, jelly-like substance inside the cell membrane that contains the other organellesYes
RibosomeSmall bodies floating in cytoplasm (or attached to the endoplasmic reticulum) that make proteinsYes

Cell movement structures

FlagellaWhip/tail-like structure that helps propel the cell forward
CiliaShort, hair-like structure that surround the cell and help it move
PseudopodiaExtension of cytoplasm into the cell membrane that allows the cell to “crawl”
Image modified from OpenStax College, Biology, CC BY 4.0.

What else should I know about basic cell structures?

  • All cells contain genetic information. All living things must have genetic information that provides instructions for cellular activities. Some cells keep this genetic information in a nucleus, while others store it differently.
  • The cell wall and cell membrane are not the same thing. All cells have a cell membrane, but not all cells have a cell wall. Cell walls are very rigid, which makes the cell harder to move. They can be made up of a variety of substances, so cell walls in plant cells are different than those found in bacterial cells.

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