What is the benefit of substrate channeling? The PDH active site forms in the hydrophobic core of the complex instead of a surface‑exposed region. Reaction intermediates move to sequential active sites faster than the diffusion constant. Every intermediate or product made by the PDH complex enters the citric acid cycle as a substrate. The PDH complex sequesters excess substrate to use at later time. Intermediates of a multistep reaction sequence do not dissociate from the enzyme complex.

Intermediates of a multistep reaction sequence do not dissociate from the enzyme complex.

Explanation:

Substrate channeling is the process in which intermediates produced in an enzymatic reaction is transferred to another enzyme or active in a reaction pathway without the substrate having to dissociate from the enzymes active sites into the reaction medium or solution.

Benefits of substrate channeling include:

Substrate channeling is observed in the pyruvate dehydrogenase complex reaction which oxidizes pyruvate to acetyl-CoA.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.