Practice question

Eukaryogenesis entailed evolution from archaeal ancestor through acquisition of flexible cell surface allowing phagocytosis, expansion of actin-based cytoskeleton, development of endomembrane system including nuclear envelope, endoplasmic reticulum, Golgi, and mitochondria via endosymbiosis. Integral step involved loss of rigid external wall to permit membrane remodeling and vesicular trafficking. Peptidoglycan polymer of alternating N-acetylglucosamine and N-acetylmuramic acid crosslinked by peptides characterizes bacterial walls and was never retained in eukaryotic lineage, as eukaryotes use distinct glycans such as cellulose or chitin when walls exist.