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The Living Cell
The Living Cell
“Cell”– Named by Robert Hooke who used
microscope to look at cork (1663)– Described by Anton van
Leeuwenhoek who designed his own microscope to look at living cells (1676)
– “Cell Theory” developed by Schleiden & Schwann (1838)
The Living Cell
Cell Theory
– All living things are composed of cells
– The cell is the fundamental unit of life
– All cells arise from previous cells
The Living Cell
Cell membrane– Separates the “inside” from the
“outside”– Made from a bilayer of phospholipid
molecules– Allows certain certain molecules to
pass through – Has protein protein receptors to
assist other molecules – May be surrounded by a cell wall (in
plants)
The Living Cell
Nucleus– Present in eukaryotes– Controls the cell’s heredity and
chemistry– Contains DNA in chromosome pairs– “mitosis” results in 2 daughter cells
with same DNA as original cell– “meiosis” results in the production of
egg and sperm cells with ½ DNA as original cell
The Living Cell
Energy organelles– Chloroplasts
• Contains chlorophyll which absorbs energy from sunlight
• Site of photosynthesis• Found in green plants
– Mitochondria• Site of respiration• Release energy from food by
metabolism• Found in both plants and animals
The Living Cell
Photosynthesis vs. Respiration
– Photosynthesis produces energy rich glucose
– CO2 + H2O C6H12O6 + O2
(carbon dioxide + water = glucose + oxygen)
– Respiration releases energy from glucose
– C6H12O6 + O2 CO2 + H2O + energy
sunlight
The Living Cell
Energy generation in cell
Glycolysis is 1st step – breaks down glucose and produces ATP
Followed by• Respiration, in presence of oxygen• Fermentation, in absence of oxygen
The Living Cell
Other organelles– Endoplasmic reticulum
• Smooth• Rough
– Ribosomes– Nucleoli– Golgi apparatus– Lysosomes– Vesicles and vacuoles– Cytoskeleton– Centrioles
The Living Cell
Differences between plant and animal cells– Plant
• Cell wall• Large central vacuole• Chloroplasts
– Animal• None of the above• Centrioles