Question

During cellular respiration, what is the final compound that accepts the electrons that have been transferred along the respiratory chain?

		Water
		Oxygen
		Cytochrome-c-oxydase
		ATP
		NAD+

In the respiratory chain, where does the energy used for the synthesis of ATP comes from:

		Water formation
		Oxygen
		Water Dissociation
		An electrochemical gradient between the two sides of the inner membrane of the mitochondria
		Cytochrome enzymes

Answer 1

1.During cellular respiration, Oxygen is the final compound that accepts the electrons that have been transferred along the respiratory chain.

The process oF electron transport begins with the hydride ion is removed from NADH and is converted into a proton and two electrons. In electron transport chain four multiprotein enzyme complexes act as electron carriers. The electrons start with very high energy and gradually lose it as they pass through the chain. Each complex in the chain has a higher affinity for the electrons. Electrons pass from lower reduction potential complex to higHer reduction potential complex until they finally trasferred to oxygen (oxygen has the highest affinity for electrons) and reduced to H2O.

2. In the respiratory chain, the energy used for the synthesis of ATP comes from an electrochemical gradient between the two sides of the inner membrane of the mitochondria.

A mechanism of chemiosmotic coupling is the actual mechanism by which energy released from respiration is used to drive the synthesis of ATP. This model proposes that energy from electron trasport drives an active transport system, which pumps protons from mitochndrial matrix into the inner membrane space. This generates an electrochemical gradient for the protons with a lower pH in the inter membrane space than mitochondroial matrix side. The protons on the outside have a thermodynamic propensity to flow back into the matrix to equalize pH. The resulting electrochemical proton gradient across the inner membrane drives H+ back through the ATP synthase that uses the energy of the H+ flow to synthresize ATP from ADP and Pi in the mitochndrial matrix.

Mitochondrial matrix nH -NATP WADP+P: Inner Inner mitochondrial ELERON TRANSPORT CHAIN face MHzOhO2 ATP SYNTHASE инт OUTER MITOCHONDRIAL MEMBRANE General mechanism of oxidative phosphorylation. As electron is passed along the electron transport chain, some of the energy released is used to drive three respiratory enzyme complexes that pump it out of the matrix side. The resulting electrochemical proton gradient across the inner membrane flows back 4+ to through ATP synthase that uses the energy of the H+ flow to synthesize ATP from ADP and P: in the matrix side.