Cell Structure & Function Chapter 7. The Discovery of the Cell Without a tool to make them...

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Transcript of Cell Structure & Function Chapter 7. The Discovery of the Cell Without a tool to make them...

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Cell Structure & Function Chapter 7 Slide 2 The Discovery of the Cell Without a tool to make them visible cells were until the invention of the microscope 1665 - Robert Hooke used an early microscope to look at cork cells. About the same time Anton van Leeuwenhoek observed tiny organisms in pond water. http://www.youtube.com/watch?v=wzI2Rr BYZ5U http://www.youtube.com/watch?v=wzI2Rr BYZ5U Slide 3 Early Discoveries 1838 - Matthias Schleiden a German botanist concluded that all plants are made of cells. 1839 - Theodor Schwann a German biologist stated that all animals are made of cells. 1855 - Rudolf Virchow a German physician concluded that new cells can only be produced by division of existing cells Slide 4 Cell Theory All living things are made up of cells. Cells are the basic units of structure and function in all living things. New cells are produced from existing cells through cell division. Slide 5 How do microscopes work? Most use lenses to magnify the image of an object by focusing light or electrons. Types of microscopes: Light microscopes images 1 millionth of m Electron microscopes images 1billionth of m TEM transmission thin samples, can see cell structures & molecules SEM scanning 3-D surface images Slide 6 Light Microscope image Slide 7 SEM Images Slide 8 TEM Images Slide 9 Examples of Cells Amoeba Proteus Plant Stem Red Blood Cell Nerve Cell Bacteria Slide 10 As you can see cells come in many sizes and shapes Slide 11 All cells have some similarities: At some point they contain DNA All cells are surrounded by a thin flexible barrier called a cell membrane or plasma membrane. But they also have differences and so are seperated into 2 broad groups: Eukaryotes and Prokaryotes Slide 12 Prokaryotic Do not have structures surrounded by membranes Do not separate DNA within a nucleus One-celled organisms, Bacteria Slide 13 Slide 14 Eukaryotic Contain organelles, specialized structures that perform specific functions; surrounded by membranes Nucleus separates DNA from the rest of the cell Most living organisms, great variety PlantAnimal http://library.thinkquest.org/C004535/eukaryotic_cells.html Slide 15 What do these cells have In common? Slide 16 Typical Animal Cell http://web.jjay.cuny.edu /~ acarpi/NSC/images/cell.gif Slide 17 http://waynesword.palomar.edu/images/plant3.gif Typical Plant Cell Slide 18 Cell Parts Organelles Slide 19 Inside the Cell Two major parts Slide 20 Cytoplasm Gel-like mixture also called cytosol Portion outside the nucleus Surrounded by cell membrane Contains organelles of eukaryotes specialized structures that perform specific tasks Slide 21 Nucleus Directs cell activities Separated from cytoplasm by nuclear membrane Contains genetic material DNA which contains coded information to make proteins Prokaryote cells lack a nucleus but they do contain DNA Slide 22 Nuclear Membrane Surrounds nucleus Made of two layers Openings called nuclear pores allow material to enter and leave nucleus Also called the nuclear envelope http://library.thinkquest.org/12413/structures.html Slide 23 Chromosomes In nucleus Made of DNA Contain instructions for traits & characteristics Usually in the form of long thin threads called chromatin http://library.thinkquest.org/12413/structures.html Slide 24 Nucleolus Small dense region inside nucleus Involved in the assembly of organelles called ribosomes http://library.thinkquest.org/12413/structures.html Slide 25 Vacuoles Membrane-bound sacs for storage of water, salts, proteins, and carbohydrates Plants usually have a large vacuole that helps maintain shape Paramecium contractile vacuole http://library.thinkquest.org/12413/structures.html Slide 26 Lysosome Small organelles filled with enzymes to digest waste Transports digested material to cell membrane for removal Also breaks down old organelles no longer needed http://library.thinkquest.org/12413/structures.html Slide 27 Cytoskeleton Helps maintain cell shape and also in movement. Internal network of protein fibers: Microfilaments Microtubules Slide 28 Ribosomes Each cell contains thousands Make proteins using instructions from DNA http://library.thinkquest.org/12413/structures.html Slide 29 Endoplasmic Reticulum Internal membrane system where compounds are assembled and transported Smooth ER: lacks ribosomes; makes lipids Rough ER(pictured): ribosomes embedded in surface; modify proteins made by ribosomes Slide 30 Golgi Apparatus Modifies, sorts, and packages proteins and other materials from the ER for storage in the cell or released outside the cell. Bundles proteins in tiny vesicles. http://library.thinkquest.org/12413/structures.html Slide 31 Mitochondria Convert chemical energy stored in food (glucose) into compounds that are able to be used by cells ATP In humans most all of our mitochondria come from the cytoplasm of the egg cell so you got yours from your mother. They also contain their own DNA! http://library.thinkquest.org/12413/structures.html Slide 32 Chloroplast Capture energy from sunlight and convert it into food sugars that contain chemical energy in a process called photosynthesis. Surrounded by two membranes Contain pigment called chlorophyll http://library.thinkquest.org/12413/structures.html Slide 33 Surrounding the Cell Slide 34 Cell Membrane Outer membrane of cell that controls movement in and out of the cell Double layer Also known as the plasma membrane http://library.thinkquest.org/12413/structures.html Slide 35 Cell Wall Most commonly found in plant cells & bacteria Supports & protects cells http://library.thinkquest.org/12413/structures.html