Question

How do malarial parasites change the red blood cells of their hosts in order to obtain nutrients and avoid destruction?

a. They cause the red blood cells to stick to other human cells, thus preventing the red blood cells from traveling in the blood stream.
b. They cause transport proteins to be placed on the surface of the red blood cells, enabling more nutrients to be imported into the host cell.
c. They inject viruses into red blood cells, which makes the cells "invisible" to the host immune system.
d. Both a and b

Answer 1

Plasmodium parasites alter red blood cells by causing the cells to adhere to other cells and by increasing nutrient import, allowing the parasites to evade the immune system and obtain resources needed for growth.

Step-by-step explanation:

The malarial parasite Plasmodium causes malaria by altering human red blood cells (RBCs) to both obtain nutrients and evade the host's immune system. Once inside the RBCs, the parasites induce changes that include the transport of parasite-produced proteins to the cell surface. These proteins cause the RBCs to adhere to the walls of capillaries and the surfaces of other cells, a process known as cytoadherence. This sequestration of the infected RBCs prevents them from being cleared by the spleen and allows the parasite to replicate in a relatively safe environment.

Additionally, Plasmodium falciparum, one of the most lethal species, causes RBCs to import more nutrients which are essential for its own growth and reproduction. As the Plasmodium parasite matures and replicates, it eventually leads to the lysis (bursting) of red blood cells, releasing more parasites into the bloodstream and causing the symptoms of malaria including anemia and fever.