In intestinal epithelial cells, a transport protein moves the bulky, polar glucose molecules through the membrane into the cytoplasm, while simultaneously transporting na+ through the membrane into the cell down its electrochemical gradient. which example correctly describes this cotransport of glucose and sodium?
a primary active transport by an antiporter
b. secondary active transport by a symporter
c. primary active transport by a symporter
d. secondary active transport by an antiporter

b. secondary active transport by a symporter

Explanation:

Glucose is a monosaccharide, one of the digestion products of carbohydrates. Glucose is a polar molecule and can not diffuse through the hydrophobic core of the cell membrane of absorptive cells of the small intestine.

A symporter transports one glucose and two sodium ions from the cavity of the small intestine into the absorptive cells of the villi. Since both Na+ and glucose are transported in the same direction, it is a symport. Here, the energy of the ionic concentration gradient of Na+ serves as a source of energy for glucose transport, the process of glucose transport is secondary active transport.

after a the power stroke, adp is released, but the cross-bridge formed is still in place. atp then binds to myosin, moving the myosin to its high-energy state, releasing the myosin head from the actin active site.