Transcript Cell Structure & Function

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
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 organelles surrounded by membranes
• Most living organisms
Plant
http://library.thinkquest.org/C004535/eukaryotic_cells.html
Animal
Cell Structure
& Function
http://koning.ecsu.ctstateu.edu/cell/cell.html
“Typical” Plant Cell
Cell wall
cytoplasm
Cell membrane
vacuole
Endoplasmic
Reticulum
nucleus
nucleolus
Nuclear membrane
mitochondria
ribosome
Golgi aparatus
chloroplast
http://waynesword.palomar.edu/images/plant3.gif
“Typical” Animal Cell
Cell membrane
cytoplasm
nucleus
nucleolus
Endoplasmic
Reticulum
Nuclear membrane
lysosome
mitochondria
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
ribosome
Golgi aparatus
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/AnimalCel
lStructure/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/Anato
my/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