Chemotaxis is a process by which cells migrate toward higher concentrations of a signaling molecule. The signaling binds cell-surface receptors that result in actin polymerization at the cell membrane. Actin polymerization results in the formulation of filamentous actin that exerts a force and leads to protrusion of the leading edge. A researcher tested Compound A on chemotaxing cells and measured the relative amount of filamentous actin found in the cells at different times. Part A. Which of these structures, if present in a prokaryote, would prevent the organism from using this type of actin polymerization to chemotax toward a signal? Cell wall, flagellum, mitochondrion, or ribosome?
The prokaryotic structure that would prevent actin polymerization and chemotaxis is the cell wall. The cell wall is a rigid structure that surrounds the cell membrane in prokaryotes, and it would hinder the ability of the cell membrane to undergo actin polymerization and protrusion of the leading edge required for chemotaxis. The other structures mentioned (flagellum, mitochondrion, ribosome) are not directly involved in actin polymerization and would not prevent chemotaxis.
