MBB 222 Chapter Notes - Chapter 1: Symbiogenesis, Signal Transduction, Pseudopodia
20 Dec 2018
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The fact that animal cells lack a rigid cell wall allows them to alter the shape of the plasma membrane, using components of the cytoskeleton called microtubules. It is thought that mobile ancestral eukaryotic cells were predators that sought out and engulfed other cells as a source of nutrients. This behavior can still be seen in mammalian macrophage cells, which are protective cells in the immune system that seek out and destroy invading microorganisms or abnormal cells based on identification of foreign cell surface proteins. The endosymbiotic theory proposes that eukaryotic cells evolved about 1. 5 billion years ago as a result of large predatory cells engulfing aerobic bacteria, which eventually gave rise to mitochondria. The symbiotic bacteria were able to use o2 in the atmosphere as an electron acceptor in oxidation reduction reactions, which provided a form of chemical energy for the synthesis of atp.
