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The Cell. A Little History. Robert Hooke English scientist; looked at a slice of cork under a compound microscope Observed small, room-like structures that he called cells Because they reminded him of the rooms monks live in He only saw the cell walls because cork cells are already dead.
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A Little History • Robert Hooke • English scientist; looked at a slice of cork under a compound microscope • Observed small, room-like structures that he called cells • Because they reminded him of the rooms monks live in • He only saw the cell walls because cork cells are already dead
A Little History • Anton van Leeuwenhoek (1674) • Dutch fabric merchant and amateur scientist • Looked at blood, rain water, and scrapings from teeth through a simple microscope (one lens) • Observed living cells and improved the quality of the microscope
A Little History • Matthias Schleiden(1838): viewed plant parts under a microscope; discovered plant parts are made of cells • Theodore Schwann(1839): viewed animal parts under a microscope; discovered animal parts are made of cells • Rudolph Virchow(1855): stated that all living cells come only from other living cells
Cell Theory • All living things are made up of cells. • Cells are the smallest working units of all living things. • All cells come from preexisting cells through cell division.
Definition of Cell A cell is the smallest unit that is capable of performing life functions.
Examples of Cells Amoeba Proteus Plant Stem Bacteria Red Blood Cell Nerve Cell
Two Types of Cells Prokaryotic Greek roots: [pro]=before,[karyon]=kernel (refers to the nucleus) In domains Bacteria and Archaea Eukaryotic Greek roots: [eu]=true, [karyon]=kernel (refers to the nucleus) Domain Eukarya
Prokaryotic • Do not have structures surrounded by membranes-no nucleus • Few internal structures • One-celled organisms • Bacteria http://library.thinkquest.org/C004535/prokaryotic_cells.html
Eukaryotic • Contain organellessurrounded by membranes • Most living organisms Plant Animal http://library.thinkquest.org/C004535/eukaryotic_cells.html
Cell Structure & Function http://koning.ecsu.ctstateu.edu/cell/cell.html
“Typical” Plant Cell cytoplasm Cell wall Cell membrane vacuole Endoplasmic Reticulum nucleus nucleolus Nuclear membrane ribosome Golgi aparatus mitochondria chloroplast http://waynesword.palomar.edu/images/plant3.gif
“Typical” Animal Cell Cell membrane cytoplasm nucleus Endoplasmic Reticulum nucleolus Nuclear membrane ribosome lysosome Golgi aparatus mitochondria http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
Cell Parts Organelles
Cell (Plasma) Membrane • Controls movement in and out of cell
Cell Wall • Most commonly found in plant cells & bacteria • Supports & protects cells • Plant cell walls are mostly made of cellulose http://www.yellowtang.org/images/cell_walls_in_plant_c_ph_784.jpg
Nucleus • “the information center” or “brain” of the cell • Contains genetic material – Chromosomes (DNA) http://www.cartage.org.lb/en/themes/Sciences/Zoology/AnimalPhysiology/Anatomy/AnimalCellStructure/Nucleus/cellnucleus.jpg
Nuclear Membrane • Surrounds nucleus • Has pores that allow mRNA to move out of nucleus http://www.microscopy.fsu.edu/cells/nucleus/images/nuclearenvelopefigure1.jpg
Nucleolus • Specialized region in the nucleus where ribosome subunits are made http://www.microscopy.fsu.edu/cells/nucleus/images/nucleolusfigure1.jpg
Cytoplasm • Portion of the cell outside of the nucleus • Gel-like substance
Endoplasmic Reticulum, ER • Manufactures products for secretion • Smooth ER: lacks ribosomes • Makes and packages lipids • Rough ER: ribosomes embedded in surface • Makes and packages proteins
Ribosomes • “Work benches” for protein synthesis • Found on the Rough ER & floating throughout the cell http://publications.nigms.nih.gov/insidethecell/images/ch2_ribosome_proteinbig.jpg
Mitochondria • Energy Organelle • Breaks down glucose to produce energy packets (ATP) for the cell • Contains its own DNA http://www.cartage.org.lb/en/themes/sciences/zoology/AnimalPhysiology/Anatomy/AnimalCellStructure/Mitochondria/mitochondria.jpg
Golgi Bodies • Modifies, sorts and packages proteins and other products for distribution
Lysosome • Bags of enzymes that break down old organelles and bacteria • Keeps the cell clean http://publications.nigms.nih.gov/insidethecell/images/ch1_lysosome.jpg
Vacuoles • Membrane-bound sacs for storage, digestion, and waste removal • Much larger in plants • Help plants maintain shape
Chloroplast • Usually found in plant cells • Contains green chlorophyll • Where photosynthesis takes place http://www2.mcdaniel.edu/Biology/botf99/cellstructure/chloroplast..jpg
flagella • Long, slender, whip-like projection used for movement
cilia • Small hair-like structures found on the surface of cells used for movement