Question

what role is the pyruvate in cellular respiration

Answer 1

t's A, an electron carrier. It's not an enzyme but a coenzyme (which is an organic molecule that attaches allosterically/non competitively or competitively on active site, but in this case attaches in active site). It doesn't provide energy, yet.... because NAD+ is in it's oxidized form. When it acts as an oxidizing agent for glucose, it will become reduced (gain 2 electrons.. and one proton) to NADH (which is what releases the energy step-by-step in the ETC).