cell structure & function. a little history 1600’s – cork cells – robert hooke
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Cell Structure & Function
A Little History• 1600’s – cork cells – Robert Hooke
Anton van Leeuwenhoek-1600’s
• Observed “animalcules”
Anton’s Words
• . . . my work, which I've done for a long time, was not pursued in order to gain the praise I now enjoy, but chiefly from a craving after knowledge, which I notice resides in me more than in most other men. And therewithal, whenever I found out anything remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof.
Antony van Leeuwenhoek. Letter of June 12, 1716
Matthias Schleiden – 1800’s
• Plant Biologist – started as lawyer
• Father of cell theory
• One of first German
scientists to accept
Darwin’s theory of
Evolution
Theodor Schwann -1800’s
• Medicine – physiology
• Met with Schleiden
• Helped with cell
theory after realizing that nucleus was in both plant and animal cells
Rudolf Virchow – 1800’s
• Studied cell division
• Completed cell theory
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.
Janet Plowe – 1900’s• Showed that the cell membrane is an
actual structure
George Langford - now
• Studied movement of vesicles along the cytoskeleton
• Both myosin tubules and actin filaments
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
• Sizes of cells (Click)
Two Types of Cells
•Prokaryotic
•Eukaryotic
Prokaryotic
• Do not have structures surrounded by membranes
• 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
“Typical” Animal Cell
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
http://waynesword.palomar.edu/images/plant3.gif
“Typical” Plant Cell
Cell Parts
Structures/Organelles
Cell Membrane• Outer membrane of cell that controls movement
in and out of the cell• Double layer
Cell Wall
• Most commonly found in plant cells & bacteria• Supports & protects cells
Nucleus • Directs cell activities
• Separated from cytoplasm by nuclear membrane
• Contains genetic
material - DNA
Nuclear Membrane• Surrounds nucleus• Made of two layers• Openings allow
material to enter
and leave
nucleus
Chromosomes
• In nucleus• Made of DNA• Contain instructions
for traits & characteristics
http://library.thinkquest.org/12413/structures.html
Nucleolus• Inside nucleus• Contains RNA to build
proteins
Cytoplasm• Gel-like mixture filled with proteins
• Surrounded by cell membrane
Rough Endoplasmic Reticulum
• Moves materials around in cell
• ribosomes embedded in surface
• New proteins are twisted and folded
Smooth Endoplas-
mic Reticulum• No ribosomes• Synthesize lipids• Site for enzyme action• Storage of enzymes
Ribosomes
• Each cell contains thousands
• Make proteins
• Found on ER & floating throughout the cell
Mitochondria
• Produces energy
through chemical
reactions – breaking
down fats &
carbohydrates• Controls level of water
& other materials in cell• Recycles and
decomposes proteins,
fats, and carbohydrates
Golgi Bodies• Protein 'packaging plant'• Move materials within
the cell• Move materials out of the
cell
Cytoskeleton
• Composed of proteins
• Movement of vesicles
• Support for cell
• Cilia, flagellae, cell division
Lysosome• Digestive 'plant' for proteins,
fats, and carbohydrates• Transports undigested
material to cell membrane for removal
• Cell breaks down if lysosome explodes
Peroxisome
• Oxidative enzymes - catalase• Self- replicating• Do not form at Golgi Body• Rid body of toxins such as hydrogen peroxide
Vacuoles – vesicles
• Digestion
• Secretion
• Transport
• Water - vacuole
Vacuoles – in Plants
• Membrane-bound sacs for storage, digestion, and waste removal
• Contains water solution
• Help plants maintain shape
Chloroplast - Plant• Where
photosynthesis takes place
• Contains
chlorophyll• Found in
plants,
protists
Centrosome/Centrioles - Animal• Involved in cell division – formation of spindle
• Microtubule Organizing Center