CELLS: UNITS OF LIFE. Chapter 4 Hyperlink is the 3 rd one that says component of cells – same as above, but narrated!. The Discovery of Cells. All organisms consist of cells. The Discovery of Cells. Cells – the place where biochemical activity occurs. The Discovery of Cells.
Hyperlink is the 3rd one that says component of cells – same as above, but narrated!
The Cell Theory Emerges – not till 19th Century
1. All living things are composed of cells. [Schleiden & Schwann]
2. All cells come from preexisting cells. [Virchow]
Cell Theory still evolving: Organelles have precise locations in cells
C. Types of Cells
3 basic types:
Review surface area to volume relationship – Large volume justifies the need to have organelles
Folding membranes also increase surface area for reactions
Ex. bacteria & cyanobacteria
Distinguishes 2 types of bacteria
Structure of a Gram-Negative Cell Wall
Gram positive cell wall
Ex. Extremophiles: extreme environments: temp, pressure, pH, salinity
methanogens, extreme halophiles & extreme thermophiles
Animal Cell Plant Cell
Leopard spot retinal pigmentation and morePeroxisomes, con’t
2. Endoplasmic reticulum and more(ER)
interconnected network of membranes extending from nucleus to plasma membrane
3. Golgi apparatus and more
4. Lysosomes (suicide sacs) and more
5. and morePerixisomes
6. Mitochondria and more
7. and moreChloroplasts
E. and moreThe Endosymbiont Theory
Proposes that chloroplasts and mitochondria evolved from once free-living bacteria engulfed by larger archaea.
Based on fact that mitochondria & chloroplasts resemble certain bacteria (size, shape, membrane structure & method of making proteins).