Ricin is one of the most powerful toxins known. The protein consists of two subunits: the A chain is an enzyme that inhibits translation and the B chain is a lectin that binds to carbohydrates on the cell surface. What is the most likely mechanism by which ricin enters the cell

a. The protein is internalized by endocytosis.

b. The A chain binds to clathrin. The B chain interacts with SNARES

c. The A chain stimulates autophagy

d. The protein enters through pore complexes in the plasma membrane.

The correct option is a

The protein is internalized by endocytosis.

Explanation:

The protein is internalized by endocytosis because Ricin is a potent toxin gotten from lecithin. It internalised in the intracellular cell by endocytosis or substances are brought inside the cell and translocated into the cystosol which hereby inhibit protein synthesis and kill the internal cells. These internal toxins are transported to lysosomes for degradation

phylogenetic tree is the tree of life or evolution tree. it shows the different branches of evolution. the sequence goes like tissues - coelom - backbone - endoskeleton - segmentation

i might be wrong but i think its a. let me know if i’m right and have a good rest of your day!