01.03 Cell Structure

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Included In This Lesson



  1. Introduction to Cell – smallest unit of life
    1. Eukaryotic Cells
      1. Do contain a nucleus and membrane-bound organelles
      2. Ex. Animal and Plant Cells
    2. Main Structures of Eukaryotic Cells
      1. Cell Membrane
        1. Structure – mainly composed of
          1. Phospholipids – non-polar fatty acid tails that form a bi-layer
          2. Proteins – peripheral vs. integral/embedded transport proteins, ion channels
        2. Functions – Gate Keeper that controls what enters/leaves a cell
      2. Cytoplasm
        1. Cytoskeleton – Solid infrastructure of cell
        2. Cytosol – fluid-like medium of cell
      3. Nucleus
        1. DNA/Chromosome – stored genetic information
        2. Nucleolus – where RNA and ribosomes are produced
    3. Other Organelles which include
      1. Membranous Organelles
        1. Rough Endoplasmic Reticulum
        2. Smooth Endoplasmic Reticulum
        3. Golgi Apparatus
        4. Mitochondria
        5. Lysosomes
      2. Non-Membranous Organelles
        1. Ribosomes
        2. Filaments
        3. Microtubules
        4. Cilia & Flagella


In this lesson we are going to review some of the important structures of the cell that make up us!

And those cells that make up us (as humans/animals) are called eukaryotic cells. So an easy way to remember this by ephasiszing the EU- in eukaryotic! So it is these types of cell that contain a nucleus and other membrane-bound organelles.

So here are two perfect examples of eukaryotic cells, plant and animal cells and as you can see they contain a nucleus and other organelles surrounded by a membrane. 


It is important to mention that all cells, including eukaryotes are surrounded by a cell membrane. This membrane acts more like a liquid than a solid and is comprised mainly of a phospholipid bilayer that does a great job of lining the cell with a protective layer whose design is selectively permeable. So the layer in the middle (those fatty acid tails) are great at keeping a thin layer of separation between what is in the  cell and its surrounding environment. Additionally embedded in the phospholipid bilayer are two main types proteins. Peripheral proteins (like your peripheral vision) are usually just on one side of the membrane and integral proteins are found on both sides of the membrane layer and typically act as tunnels are shoots for materials to pass through. So certain types of molecules that are polar (like water) or large in size (like glucose) have their own special channel/tunnel that allow them to pass through the membrane via the protein channels.  So just like an organism needs to take in nutrients and get rid of wastes, this needs to happen on a cellular level as well and the design of the cell membrane makes this possible in a very selective manner.

Additionally eukaryotic cells have a cytoplasm. The solid portion allows a cell to hold or change its shape as needed, much like the scaffolding of a building is designed to hold its shape. The other part of the cytoplasm is the fluid like ortion that also holds the organelles in place and acts a a medium for chemical reactions is the cytosol, the liquid-like portion of the cytoplasm. This graphic here is showing the breakdown of where fluids are found in our body, and you can see 67% is intracellular fluid, that’s cytosol in our cells.

Eukaryotic cells have a nucleus. You can see it here stained in blue. That’s all genetic material stored in the nucleus. ANd of course also in the nucleus is the dark spot called the nucleolus, where RNA and ribosomes are created. 

Point out and briefly mention the organelles  listed: 


Rough ER #5

Smooth ER #8


Mitochondria #9

Lysosomes #12

Vesicle #4

Cell Membrane #14

Nucleus #2

Nucleolus #1

Vacuole  #10



Cytoskeleton: Microtubules/Filaments  #7

Cytosol #11

Not pictured 


Centrioles #13

So in summary,

YOU as an animal are made up of eukaryotic cells.

All  Cells are surrounded by a viscous, semi-permeable membrane made up of lipids and proteins that acts like a gatekeeper for what comes in and leaves the cell.

All cells contain cytoplasm that has a more solid cytoskeleton to maintain shape and a fluid-like cytosol for solutes and enzymatic reactions to occur.

All eukaryotic cells contain a nucleus where genetic material called chromosomes are housed.

Cells contain organelles that are surrounded by a membrane as well as those that are not. Organelles serve as little protected compartments for specific functions to take place necessary for the cell to maintain balance. 

Thank you very much for joining us today to investigate eukaryotic cell structures. Now go out and be your best self today and Happy Nursing!