Biology C1/2 Flashcards
Cell Theory
1) All living things are made up of one or more cells
2) Cells are the smallest functional unit of life
3) All cells are produced by the division of other pre-existing cells
Robert Hooke
The first person to observe and describe cells
Antonie van Leeuwenhoek
Observed the first living cells and called them “animalcules”
Botanist Matthias Schleiden
Stated that plants were made up of cells
Zoologist Theodor Schwann
Stated that animals were made up of cells
Robert Brown
Discovered the nucleus in plant cells
Francesco Redi
Disproved the theory of spontaneous generation
Louis Pasteur
Proved beyond a reasonable doubt that spontaneous generation of life does not now occur
Rudolph Circhow
Observed cells dividing and stated that new cells are formed by the division of pre-existing cells
Light Microscope
Visible light is passed through a specimen, and then one (simple) or two (compound) glass lenses. The lenses refract the light
Transmission Electron Microscope
A beam of electrons is passed through a very thin section and electrons that pass through fall on photographic film - produces clear images of interior
Scanning Electron Microscope
Electrons reflected off a specimen covering with an electron-dense material (gold) - produce 3-D image of the surface
Prokaryotic Cells
- Smaller than eukaryotic cells
- Lack membrane-bound organelles
- Earth’s first inhabitants
Eukaryotic Cells
- Larger than prokaryotic cells
- Have a true nucleus and membrane-bound organelles\
- Evolved from prokaryotic cells
- Involves animal and plant cells
Organelles
Membrane-bound structures inside eukaryotic cells that have specialized functions
Cell Wall
Rigid outer layer made up of cellulose that maintains the cell’s shape and protects the cell from mechanical damage. Only in plant cells.
Cell Membrane
Flexible phospholipid bilayer surrounding the cell, that serves as a selectively permeable barrier between he inside and outside of the cell
Cytoplasm
A semifluid, jellylike substance containing dissolved substances, in which organelles and other components are found