Cell Theory Flashcards
understand what the cell theory is, and cells that do not follow the theory.
what are the three key points included in the cell theory?
- all living things are composed of cells
- cells are the smallest unit of life
- cells only arise from pre-existing cells
what are some examples of cells that do not follow the cell theory?
- striated muscle cells
- aseptate fungal hyphae
- giant algae
why do striated muscle cells not follow the cell theory?
-the muscle cells fuse together, to become very long fibres at greater than 300mm
-as a result, they then have multiple nuclei, despite being surrounded by a single continuous plasma membrane
-this then goes against the idea, that cells always function as autonomous units.
why do aseptate fungal hyphae cells go against the cell theory?
-fungi have filamentous structures, that are called hyphae, and are separated into cells, by internal walls, that are called septa
-however, some fungi do not have septa to partition the cells, and as a result, they form a continuous cytoplasm along the hyphae.
-this then means that these cells do not follow the idea that living structures are composed of discrete cells.
why do giant algae cells not conform to the cell theory?
-some algae species can grow to very large sizes, that exceed 7cm in length
-this then challenges the idea, that larger organisms are always made of many microscopic cells.
