Chemotaxis Lab Report

Chemotaxis is the directional migration of cells in response to a chemical stimulus. The movement of these cells can either be directed towards favourable chemicals (chemoattractants) or unfavourable chemicals (chemorepellents). In particular, sugars and amino acids can attract many species of bacteria via chemotaxis, and the main method used to identify these chemicals is an assay that uses a glass capillary (Abe et al., 2017). In the capillary assay, the outer chamber contains mobile cells while the inner chamber contains the chemical to be tested. If the chemical is a chemoattractant, the cells will migrate in the inner chamber. If it is a chemorepellent, they will remain in the outer chamber. The process of chemotaxis gives the ability to observe an organism’s behavior when presented with food, as demonstrated in this experiment with the single-celled organism Tetrahymena. …show more content…
They are largely motile and contain cilia on the surface that assist with movement and gathering food. The process by which T. thermophila obtains most of its nutrients is called phagocytosis. During phagocytosis, particles are consumed by a portion of the plasma membrane. This results in the formation of a vesicle, or phagosome, which then fuses with a lysosome in the cytoplasm to break down and digest food particles. However, a large fraction of bacteria engulfed by protozoa are not digested. Instead, they remain metabolically active and survive to be discharged to the outside environment (Aijaz and Koudelka, 2017). The discharge of these indigestible materials occurs when the membrane of the phagosome reaches the opposite end of the plasma membrane and fuses with it to release the