Cell Organelles Eukaryotic Cells

Cells– (the smallest unit of life)- make up all living things, including your own body.

Some organisms, like bacteria are unicellular – (one cell)-, but Multicellular –(made of more than one cell)- organisms, like humans, may consist of trillions of cells. On the outside, plant and animals look very different, but if you examine their cells you’ll see that they have many similarities.

Can we see cells? In the mid 1600’s scientists Robert Hooke and Anton Van Leeuwenhoek invented basic microscopes and observed cells for the first time.

Many structures in the cell are too small to see with a light microscope. In the 1950s, scientists developed more powerful microscopes. A light microscope sends a beam of light through a specimen, or the object you are studying. A more powerful microscope, called an electron microscope, passes a beam of electrons through the specimen. Sending electrons through a cell allows us to see its smallest parts, even the parts inside the cell (Figure below). Without electron microscopes, we would not know what the inside of a cell looked like.

The outline of onion cells are visible under a light microscope.

An electron microscope allows scientists to see much more detail than a light microscope, as with this sample of pollen.

Cell Theory Cell theory states that: Between 1838 and 1855 Matthias Schleiden, Theodore Schwann, and Rudolf Virchow developed the Cell Theory . Cell theory states that: All living things are composed of cells. Cells are the basic unit of life. All cells come from other cells. As with other scientific theories, many hundreds, if not thousands, of experiments support the cell theory. Since scientists developed the theory, no evidence has ever been identified to contradict it.

Cell Parts Cells – the basic unit of life Organelles - small structures inside a cell with specific functions. Like a small city

What are the different parts of cells and what does each do?

Cell Membrane/Plasma Membrane Function: Regulates materials entering and exiting the cell. Structure: Two layers of phospholipids, proteins City limits

Cytoplasm Fruit in a Jello mold Function: All cell contents that lie between the cell membrane and the nucleus. (organelles + cytosol) a. Cytosol = liquid portion/non-organelles. Structure: made up of fluid and organelles except for nucleus Fruit in a Jello mold

Nucleus Function: “Control Center.” Regulates DNA & RNA actions. Structure: membrane bound, contains DNA Instructions to maintain stability in a crazy world

Nuclear Envelope Function: Regulates what enters or exits the nucleus. Structure: Double Layer of Lipids Portals for instructions

Nucleolus Function: Produces RNA, which are used to make all proteins. Structure: Inside Nucleus, separate from DNA Brain of the cell

DNA – Deoxyribonucleic acid DNA (chromatin) Function: information on how to make proteins. Chromatin – unorganized DNA (normal state) Chromosomes – organized DNA (present before cell division Structure: Made up of nucleotides, locked in the nucleus The Laws or City Code

Endoplasmic Reticulum Rough ER Smooth ER Function: Transportation route for proteins. Rough ER: has ribosomes Smooth ER: no ribosomes Structure: tubes and channels Roads & Sidewalks

Ribosomes Function: Makes proteins. Free Ribosomes Function: Makes proteins. Structure: small circular organelles Protein factories

Vacuoles & Vesicles Function: Storage for water, nutrients or waste. Structure: small membrane-bound organelle. Packages

Lysosomes Lysosomes Function: packets of enzymes that break down materials in a cell. Structure: Small membrane-bound organelles The clean up crew

Mitochondria Mitochondria Function: Produce energy for the cell – site of cellular respiration. “The Powerhouse” Structure: Double membrane-bound, kidney shaped. Engine that runs on sugars

Golgi Apparatus Golgi Apparatus Function: Packages, labels and ships proteins out of the cell. Structure: Pancake-shaped layered organelle UPS delivery

Cytoskeleton Function: Provide support and structure for the cell. Microfilaments Microtubules Function: Provide support and structure for the cell. Microfilaments Microtubules Structure: Tubules Scaffolding for cells

Centrioles (Animals Only) Function: microtubules that help divide the cell during cell division. Structure: Tubules

Cilia & Flagella Cilia Flagella Flagella Function: provides movement for the cell or objects moving by the cell. Structure: Flagella – 1 long fiber Cilia – many short fibers Analogy – Cars or bicycles.

Chloroplasts (Plants only) Function: site of photosynthesis (converting sun and CO2 into sugar). Structure: Membrane bound organelles that contain chlorophyll Solar Panels for a leaf

Cell Wall (Plant cells only) Function: Provides support for the cell and the plant. Structure: Made of cellulose Analogy – ground, rock wall

Create an analogy (besides the city analogy) for the cell and its parts Possible ideas: Stadium School Country Restaurant House Mall Waterpark Cell Parts Analogy

Stadium Example: Cell membrane: wall of stadium, gates Cytoplasm: everything inside the stadium. Nucleus: the control room for the stadium. Etc…