1. All living things are composed of cells (or cell products)
2. The cell is the smallest unit of life
3. Cells only arise from pre-existing cells
2.1.2 Discuss the evidence for the cell theory
Microscopes:
Microscopes have increased man's ability to visualise tiny objects
All living things when viewed under a microscope have been found to be made of cells and cell products (e.g. hair)
Note: Certain types of cells do not conform to the standard notion of what constitutes a cell
Muscle cells contain multiple nuclei
Fungal hyphae consist of multiple cells that share a continuous cytoplasm
[pic] Light vs Electron Microscopes
Experimental Evidence:
Cells removed from tissues can survive independently for short periods of time
Nothing smaller than a cell has been found to be able to live independently
Experiments by Francesco Redi and Louis Pasteur have demonstrated that cells cannot grow in sealed and sterile conditions
[pic] History of the Cell Theory
2.1.3 State that unicellular organisms carry out all the functions of life
Unicellular organisms (such as amoeba, paramecium, euglena and bacterium) are the smallest organisms capable of independent life.
All living things share 7 basic characteristics:
Movement: Living things show movement, either externally or internally
Reproduction: Living things produce offspring, either
