The Cell
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Transcript of The Cell
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
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
1. All living things are made up of cells.
2. Cells are the smallest working units of all living things.
3. 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
Red Blood Cell
Nerve Cell
Bacteria
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 organelles surrounded 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
http://waynesword.palomar.edu/images/plant3.gif
“Typical” Plant Cell
cytoplasm
ribosome
Golgi aparatus
vacuole
Cell wall
Cell membrane
nucleus
nucleolus
Nuclear membrane
mitochondria
chloroplast
Endoplasmic Reticulum
“Typical” Animal Cell
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
Cell membrane
nucleus
nucleolus
Nuclear membrane
lysosome
mitochondria
cytoplasm
ribosome
Golgi aparatus
Endoplasmic Reticulum
Cell Parts
Organelles
Surrounding the Cell
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
Inside the Cell
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