Biology Chapter 7 Notes
I.
II.
III.
Cell Theory
A.
Discovered since 1600 by several scientists including Robert Hook, Anton van
Leeuwenhoek, Matthias Schleiden, Theodor Schwann, and Rudolf Virchow
B.
Generally defined by 3 statements
1.
All living things made up of cells
2.
Cells are basic units of structure and function in living things
3.
Cells only come from other cells
Studying the Cell
A.
Researchers use microscopes to study the cell and its structures
1.
Light microscopes
2.
TEMs
3.
SEMs
4.
Scanning Probe Microscope (2 types)
B.
Limitations of each type
1.
Only can magnify to a maximum of 1000x and light refracts therefore cannot see
extremely small cells or parts of small cells
2.
Must operate in a vacuum and dry
3.
Must operate in a vacuum and dry, only surfaces not interior
4.
Newest (1990s) uses small probe to scan surface
Two Main Types of Cells
A.
Prokaryotic
1.
No true nucleus, DNA “floats” in a nucleoid region within the cell
2.
Few if any, organelles
3.
Simplest cells
4.
Has a membrane and cytoplasm
B.
Eukaryotic
1.
Has a nucleus for holding DNA (separated from cytoplasm by a membrane)
2.
Contains many organelles
3.
Has a cell membrane and cytoplasm; some also have a cell wall
4.
Large and complex; may be unicellular or multicelluar