Question

Which of the following is NOT true of phospholipases?

They are activated in response to extracellular signals.

The products that they produce function as second messengers.

They hydrolyze specific ester bonds that connect the different building blocks that make up a phospholipid molecule.

They synthesize membrane lipids using acetyl coenzyme A as a source for carbons.

Answer 1

The option that is not true with regard to Phospholipases is Option 4- They synthesize membrane lipids using acetyl coenzyme A as a souce of carbon.

The most abundant phospholipids are made from glycerol and are called glycerophospholipids and are synthesized from fatty acyl coA. For this, phospholipases are are not involved.

All the remaining options are true while concerning phospholipids. They are activated in response to extracellular signals. Binding of a ligand, for example Growth factor results the activation of Phospholipase C (PLC).

The phospholipase C that plays a central role in signal transduction releases the second messenger Inositol triphosphate (IP₃).

And phospholipase, as the name implicates is an enzyme that hydrolyze phospholipids into fatty acids. Hence the third option is also correct.