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Cell parts and functions

Review your understanding of cell parts and functions in this free article aligned to NGSS standards.

Key points:

  • All cells have a cell membrane that separates the inside and the outside of the cell, and controls what goes in and comes out. The cell membrane surrounds a cell’s cytoplasm, which is a jelly-like substance containing the cell’s parts.
  • Cells contain parts called organelles. Each organelle carries out a specific function in the cell. A cell’s organelles work alone and together to keep the whole cell functioning.
  • Mitochondria are organelles that break down sugars. This process releases energy that the cell can use.
  • The nucleus is an organelle that contains a cell’s genes.
  • Chloroplasts are organelles that carry out photosynthesis, which makes the food plant cells need to live. This food is in the form of sugars.
  • Plant cells have chloroplasts and a cell wall, but animal cells do not. The plant cell wall is outside the cell membrane, and it provides structure for the cell.
Cell diagrams showing a typical animal cell and plant cell. Image created with Biorender.com.

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