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Explore the fascinating world of cells, the basic units of all living organisms. Learn about the history of cell discovery, types of cells, and essential organelles in this informative guide.
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Chapter 3: Cell Structure and Function
What are all living things made of? All living things are made up of cells. You have seen two cells, an amoeba and a paramecium. What did you notice about their sizes? They are really small, microscopic. What is needed in order to see cells?The microscope needed to be invented and improved in order to see cells clearly
If you couldn’t see something, how would you know it exists? The invention of the compound microscope by Zacharias Janssen in the late 1500’s allowed for the study of cells to occur • Cytology is the study of cells
Cell Study and Discovery • Anton van Leeuwenhoek (1678) - Used simple scopes to see “animalcules” • First to observe bacteria and protists • Robert Hooke (1665) – Observed cork. First to use the term “cells” • Matthias Schleiden (1888) – All plants are made up of cells • Theodore Schwann (1889) – All animals are made up of cells • Rudolph Virchow (1889) – Cells come from pre- existing cells.
**The Cell Theory** • All living things are made up of cells • Cells are the basic unit of structure and function in all living things • Cells come from pre-existing cells
All living things are made up of cells. What in this room is like a cell? What is a cell? Cell – Basic unit of structure and function in all living things
Would a microscopic organism like a bacteria need to be very complex? Bacteria are simple, very small organism that can control what comes in and out of them, and can reproduce themselves because they have DNA and structures called ribosomes (for protein synthesis)
Types of cells DNA • Prokaryotic cells • Primitive cells – “before the nucleus” • *No nucleus* • No organelles surrounded by a membrane • Found in bacteria • Have only a cell wall, cell membrane, cytoplasm, DNA & ribosomes Cell Wall DNA
What about our cells that are specific to their function? Do they need to be more complex? Yes or No? Why? Since our cells have specific functions, there is a greater level of complexity
Eukaryotic *“True nucleus”* • Have membrane – bound organelles • All other kingdoms except bacteria • ContainOrganelles • Specialized structures within the cytoplasm to perform distinct processes within the cell
Comparing the Two Cytoplasm DNA Cell Membrane
Structures common to both Prokaryotic & Eukaryotic cells • Cell Membrane • Ribosomes • DNA • Cytoplasm • Cell Walls(not in Animal or some Protist cells though!)
Prokaryotic Cell - Bacteria Cell Membrane DNA
Eukaryotic Animal Cell Cell Membrane
Cytoplasm • The jelly-like fluid filled area within a cell • Like our blood plasma, contains dissolved monomers like glucose, amino acids, nucleotides, fatty acids and glycerol, vitamins and mineral plus ionic substances like NaCl
Cytoskeleton • Network of protein strands that provide support and mobility of organelles in cytoplasm. • 2 components of cytoskeleton - Microfilaments and Microtubules (both made of protein)
Nuclear Membrane Nucleus • Only in Eukaryotic cells. • *Stores hereditary information (DNA). • Surrounded by a double nuclear membrane or envelope w/ pores . • Nucleolus(1 or >) produces ribosomes DNA Nucleolus
Mitochondria - *Powerhouse of the cells. - Supplies energy to the cell (*Site of Cellular respiration) - Double membrane with inner membrane folded to increase surface area - Has its own DNA and ribosomes and can replicate themselves! - Found in greater numbers in cells such as muscle cells & liver cells (2500/cell) Cristae Double Membrane
Ribosomes – Most numerous organelle. *Site of protein synthesis.Link amino acids together to form proteins Made up of RNA and protein. May be free floating in cytoplasm or attached on Endoplasmic Reticulum
Endoplasmic Reticulum – Maze of folded channels connected to the nuclear envelope. . • There are two types of ER: 1 – Rough w/ ribosomes attached for production & distribution of proteins. 2 – Smooth – Synthesis of lipids& detoxification of toxins. *Many in the liver
Golgi Apparatus (Bodies) – Stack of smooth flat sacs - Modifies, collects, packages & distributes molecules to all parts of a cell
Lysosomes - *Stores digestive enzymes • Are the cells' garbage disposal system. They breakdown worn out organelles • Clean up dead cells • Responsible for the un-webbing of hands of fetus while developing in utero • These are rare in plant cells
Vesicles • Temporarily isolate and transport specific molecules • Proteins produced in the RER • Lipids produced in the SER • End up in Golgi Apparatus to be processed.
Vacuoles - *Stores food, water and wastes - Plant cells have a very large central watervacuole for support Acts like a giant water balloon that pushes on the cell wall - Animal cells have many small vacuoles
Centrioles – Found in animal cells 2 perpendicular bundles of microtubules - Function during cell division
Cell Wall • Found in plants, algae, fungus and bacteria • Gives cell rigidity, support and protection. • Made up of cellulose with pectin (glue) between adjacent cells.
Chloroplasts - found in leaves and some stems Convert solar energy into energy rich molecules (glucose) - Photosynthesis • Contain Chlorophyll, DNA and ribosomes • They can replicate as needed (with more sunlight)
What does a plant cell have that an animal cell does not? What does an animal cell have that a plant cell does not?
Cell Membrane – Present in ALL CELLS. • Separates the cell’s internal environment from the external environment. • Allows for the passage of some substances based on size and concentration • Selectively Permeabledue to pores being present
Made of a double layer of phospholipidswith proteins floating through it. • Outer part of membrane is made up of polar, hydrophilic heads • Inner part of membrane is made up of nonpolar, hydrophobic fatty acid tails • Proteins through membrane allow for passage of materials across the membrane
In the "fluid mosaic model" of membrane structure says that the molecules within the membrane move around. • Phospholipids regularly move sideways & flip • Proteins can not flip around Rap
Cheek Cells Nucleus Cytoplasm Cell Membrane
Typical Animal Cell • Nucleolus • Nucleus (envelope) • Rough Er • Vesicle • Ribosome • Golgi Apparatus • Cytoskeleton • Smooth ER • MITOCHONDRIA 10. Vacuole 11. Cytoplasm 12. Lysosome 13. Centrioles Go to cellsalive.com
Nucleus • Ribosomes • Mitochondria • Chloroplasts • Cell Membrane • Cytoplasm • Cell Wall • Central Vacuole • Golgi Apparatus • Rough Endoplasmic Reticulum Typical Plant Cell
1. _______________ 2. _______________ 3. _______________ (Dots) 4. _______________ 5. _______________ 6. _______________ 7. _______________ 8. _______________ 9. _______________ 10._______________ 11._______________ 12._______________ 13._______________
Typical Animal Cell • Nucleolus • Nucleus • Ribosome • Vacuole • Rough ER • Golgi Apparatus • Microtubule • Smooth ER • Mitochondria 10. Vacuole 11. Cytoplasm 12. Lysosome 13. Centriole Typical Animal Cell