Indicate if the following statements about membrane proteins are true or false. A. They can aid in the transportation of molecules across membranes. (Click to select)B. They are used in DNA replication. (Click to select)C. They can act as cell surface receptors. (Click to select)D. They are totally water soluble. (Click to select)E. They can be enzymes. (Click to select)

A. They can aid in the transportation of molecules across membranes. TRUE

B. They are used in DNA replication. FALSE

C. They can act as cell surface receptors. TRUE

D. They are totally water soluble. FALSE

E. They can be enzymes. TRUE

Explanation:

A. They can aid in the transportation of molecules across membranes: This is the case, for example, of carrier proteins incrusted in membranes and in charge of transport. Active transport proteins are responsible for active transport. These transporters easily recognize a molecule and drive it into or out of the cell, an action that requires energy to occur. Also, channel protein and many carrier proteins are in charge of passive transport, which does not require energy.

C. They can act as cell surface receptors. Many proteins incrusted in cellular membranes act as receptors. A certain molecule binds to its receptor which is a protein structure that triggers an answer in the cell. As an example, we might mention neuronal communication through neurotransmitter (acetylcholine) that binds to its receptor in the postsynaptic membrane.

E. They can be enzymes. Enzymes are proteins, but not all proteins are enzymes. Some of the membrane proteins might be peripheral or integral enzymes, and their function is to catalyze reactions that must occur on the cell membrane.

hey there!

so, when you eat, your teeth chew and grind food into smaller pieces. this is mechanical digestion. then reactions aided by digestive enzymes break down large food molecules into smaller molecules. this is chemical digestion. the two processes change the food into simpler substances that can be used by the body for raw materials and energy.

hope this

tobey