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CELL BIOLOGYMrs. Stewart
Central Magnet School
Honors Biology
THE DISCOVERY OF CELLS Robert Hooke
Used an “early” Light Microscope to observe dead “cells” in bark of a Cork Oak tree
He coined the term “cells” because he described what he saw as “many little boxes” that reminded him of the cubicles, or cells, where monks live.
THE DISCOVERY OF CELLS Anton Van
Leeuwenhoek-Made
microscopes – able to grind lenses to increase magnification to 10x Hooke’s microscope
First to observe living cells Spyrogyra genus
– type of algae Termed them
Animalcules (protists)
THE CELL THEORY
All living organisms are composed of one or more cellsMatthias Schleiden – plantsTheodor Schwann – animals
Cells are the basic units of structure and function in an organism
Cells come only from the reproduction of existing cellsRudolf Virchow
TIMELINE – HISTORY OF CELL BIOLOGY
MICROSCOPES Microscopes are why scientists were
able to stop speculating and start observing and exploring the “unseen” world of living and non-living things.
Microscopes helped scientists clarify our definition of life
CHARACTERISTICS OF LIFE
Consist of cells Cells display organization Obtain and use energy to perform
chemical reactions (metabolism) Change through time (adapt) Respond to their environment/stimulus Reproduce Growth and development Homeostasis
CELLULAR ORGANIZATION
CELL DIVERSITY
Shape Cell
shapes reflect the different functions of cells
CELL DIVERSITY Size
A few cells are large enough to be seen by the “naked” eye
Surface area-to-volume ratio determines cell size. All materials needed by the cell must enter
and exit through the surface (cell membrane/wall) Nutrients come in Wastes are excreted out
As a cell becomes larger, the volume increases more than the surface area. There is a point where there is not enough surface area to sustain transport in/out of necessary materials to keep up with volume of cell.
PROKARYOTE VS EUKARYOTE
Pro = NO Eu = DO
Prokaryotes Smaller No nucleus, but a
nucleoid DNA is in one circular
chromosome No plasma
membrane No membrane bound
organelles
Eukaryotes Larger Nucleus Plasma membrane Membrane bound
organelles Organelles carry out
life processes within cell
DNA in multiple chromosomes within nucleus
CHARACTERISTICS THAT DISTINGUISH PLANT CELLS FROM ANIMAL CELLS
Cell wall Large central vacuole plastids