Cellular Organelle
Cell Wall Not found in animal cells In plants, the cell wall provides support for the cell (no skeleton) Is made of cellulose, a tough, stringy macromolecule http://www.research.umbc.edu/~marten/Research/cellwall.jpg
Cell Membrane Function: Control the movement of substances in and out – this makes it selectively permeable. Made mostly of phospholipids, which have a hydrophobic tail and a hydrophilic head, like this: Head Tail
Cell membrane, continued… These lipids form a “lipid bilayer”: Bilayer is flexible, giving the cell different shapes. Some chemicals stick out of the bilayer to allow for cell identification. Some are proteins that act as channels to allow big molecules (like sugar) to go through.
Cell membrane, still… Because the cell membrane is so flexible, and it has a broken, disjointed look to it, the model of the cell membrane is called: The Fluid Mosaic Model
Vacuole Sac filled with water and nutrients Function in plants: To give the plant support by providing Turgor pressure When the vacuole is full, it pushes the organelle towards the cell wall, which expands the cell and holds the plant upright. High Turgor Pressure When the vacuole lacks water, the plant wilts Low Turgor Pressure http://io.uwinnipeg.ca/~simmons/images/vacuole.gif
Endoplasmic Reticulum (ER) Extensive membrane system Rough ER, shown here, is covered with ribosomes Function: Transports, modifies and stores proteins generally internal transport Smooth ER Function: Transport, modification & storage of lipids creates steroid hormones and other macromolecules. http://images.google.ca/imgres?imgurl=http://www.cat.cc.md.us/courses/bio141/lecguide/unit1/eustruct/images/1536b.jpg&imgrefurl=http://www.cat.cc.md.us/courses/bio141/lecguide/unit1/eustruct/dkrer.html&h=400&w=500&sz=53&tbnid=-MPgGUwONmgJ:&tbnh=101&tbnw=126&start=3&prev=/images%3Fq%3Dmicrograph%2Bendoplasmic%2Breticulum%26hl%3Den%26lr%3D%26ie%3DUTF-8
The Golgi Apparatus Flattened sacs Function: Create lysosomes and other protein-filled vesicles Stores, modifies & packages protein for transport The process of packaging proteins happens through endocytosis http://137.222.110.150/calnet/cellbio/image/golgi%20&%20transport%20vesicles-electron%20micrograph-label.jpg
Active Transport: Two Types Endocytosis: Membrane wraps around proteins, then pinches off. Always refers to a vesicle (protein sac) ENTERING the cytoplasm. Exocytosis: The golgi apparatus receives the proteins from the Endoplasmic Reticulum, packaged in vesicles The vesicle membrane merges with the GA membrane, and releases the proteins into the GA. Always refers to a vesicle LEAVING the cytoplasm See handout Bio11 CD WWW
Lysosomes Only found in animal cells! Vesicles filled with digestive enzymes (proteins that speed up reactions) Function: Breakdown food particles and foreign objects like bacteria http://hematology.im.wustl.edu/faculty/kornfeld/lysosome.gif
Ribosomes Found all over cell: Function: Millions found in most cells. on Rough Endoplasmic Reticulum in cytoplasm in mitochondria in chloroplasts Function: Provides a site for protein synthesis Millions found in most cells. http://cellbio.utmb.edu/cellbio/rer5.jpg http://www.rockefeller.edu/rucal/journey/ribosomes.gif
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