Cell Theory, Prokaryotic and Eukaryotic Cells, and Endosymbiotic Theory Flashcards
1
Q
The Cell Theory
A
- All organisms composed of one or more cells
- Cells are the smallest units of life
- All cells come from pre-existing cells
2
Q
Evidence for cell theory
A
- Living cells can be visualized using microscopes since the 1600s
- No living organisms identified that are not made up of at least one cell
- Experimentation
3
Q
Exceptions to the Cell Theory
A
- skeletal muscle fiber cells and giant algae are large, polynucleated cells (not true individual cells)
- fungal hyphae are not always divided into indivdual cells/ they are actually multiple cells that share a continuous cytoplasm
- viruses are acellular, need host cell to care out functions of life
4
Q
7 functions of life
A
- Metabolism (chemical reactions)
- Reproduction (cell division/passing on hereditary molecules to offspring)
- Sensitivity/response (to stimuli/environment/adaptation)
- Homeostasis (internal balance/stability-temp/pH/ion levels etc.)
- Excretion (removal of the waste products of metabolism)
- Nutrition (obtaining chemical compounds for energy/growth)
- Growth (becoming larger/more complex)
5
Q
Why are cells small?
A
To maintain a high surface area to volume ratio. Cells want to maximize surface are to increase rate of material exchange and want to minimize volume for faster metabolic reaction rates
6
Q
What happens as cells grow?
A
As a cell grows the SA/V ratio decreases