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Animal Cell

An animal cell is defined as a cell which has a nucleus and organelles bounded by a very flexible membrane.  This flexible membrane is what has allowed animals (including humans) to advance and diversify so much throughout the years.

Image of animal cell

Evolution of the Animal Cell

Image of animal cell as viewed under a microscope

An animal cell as viewed under a microscope

Now in order to truly understand animal cells, let’s go back a very long time ago to when Earth was just formed.  Millions of years go by and cells evolve.  These first cells didn’t have a nucleus and were very simple structures. We call these cells prokaryotes, which still exist today.

Eventually, these prokaryotes evolved to contain a nucleus, which created a whole new group of cells known as eukaryotic cells. These first eukaryotic cells were in the form of plant cells, which have a rigid cell wall.  And, this wall held cells back from evolving faster and further.

Luckily, this cell wall was eventually lost, giving rise to a whole new category of cells known as animal cells. These new cells also gave rise to a whole new kingdom known as Animalia kingdom. Without a cell wall, animal cells were now able to move freely and form complex flexible structures like your muscles, organs, skin, and so much more!

Animal Cell Diagram

Shown below is an animal cell diagram.  Notice the nucleus and all the organelles are all contained within the flexible membrane.  Remember this is just a cartoon illustration.  These organelles look much different when looking at a cell under a microscope.  Also, start memorizing each organelle name and what they look like.  This will help out a bunch, once we start looking at each organelle individually.

Image of an animal cell diagram with each organelle labeled

Animal cell diagram with each organelle labeled

Animal Cell Organelles

Listed below is a summary of animal cell organelles and their primary function within the cell.  Click on each link to learn more about each organelle and what they look like.

  • Cell Membrane – Protects the cell and regulates molecules entering and leaving the cell
  • Cytoplasm – Helps hold the cell’s organelles in place
  • Nucleus – Stores the DNA and coordinates the cell’s activities, basically, it is the brain
  • Ribosomes – Build protein for the cell to use
  • Lysosomes – Break down waste into simple compounds for other organelles to use
  • Mitochondria – Convert oxygen and nutrients into energy
  • Endoplasmic Reticulum – Manufactures and transports chemical compounds to and from the nucleus
  • Golgi Apparatus – Modifies proteins and fats built in the cell and prepares them for storage or transports them outside the cell
  • Vacuole – Stores waste products and maintains the PH level of the cell
  • Centrioles – Help the cell divide during mitosis and meiosis
  • Peroxisomes – Digest toxic materials in the cell
  • Secretory Vesicles – Releases materials from the cell, usually waste from the cell
  • Microvilli – Absorb nutrients for the cell and help with cell movement
  • Cytoskeleton – Provides structural support for the cell
  • Microtubules – Provide structural support for the cytoskeleton and connect to chromosomes during cell division
  • Microfilaments – Provide structural support for the cytoskeleton


Written by: Lauren Lacey