Respiración celular | 4 | Cadena transportadora de electrones

Summary

In this video, the focus is on the electron transport chain (ETC), a critical phase of cellular respiration. The process occurs in the mitochondrial inner membrane, where electrons from NADH and FADH2 are transferred through protein complexes to produce ATP. As electrons pass through these complexes, protons are pumped across the membrane, creating a gradient used to power ATP synthase. The total yield is 38 ATP molecules, though glycolysis introduces a small energy cost. The video also compares traditional and newer models of ATP production in cellular respiration, providing insights into the mechanisms of energy generation in cells.

Takeaways

• 😀 The electron transport chain (ETC) is the final stage of cellular respiration and occurs in the inner mitochondrial membrane.
• 😀 The ETC consists of four protein complexes and two electron carriers: Coenzyme Q10 and Cytochrome C.
• 😀 NADH donates electrons to Complex I (NADH dehydrogenase), which allows protons to be pumped across the mitochondrial membrane.
• 😀 Electrons are passed through Complexes I, III, and IV, eventually being accepted by oxygen to form water.
• 😀 The movement of protons across the membrane creates a proton gradient, which powers ATP production.
• 😀 ATP synthase uses the proton gradient to produce ATP, with 3 ATP molecules produced per NADH.
• 😀 From the 10 NADH molecules generated in cellular respiration, 30 ATP molecules are produced.
• 😀 FADH2 contributes electrons to the ETC at Complex II, producing 2 ATP molecules per FADH2.
• 😀 A total of 4 ATPs are produced from the 2 FADH2 molecules involved in the process.
• 😀 The overall ATP yield from the entire process is 38 ATP molecules, but the transport of cytoplasmic NADH into the mitochondria consumes 2 ATPs, reducing the net yield.
• 😀 There is an alternate model that results in 30 ATPs being produced, depending on the approach used by the professor.

Q & A

What is the electron transport chain in cellular respiration?

The electron transport chain (ETC) is the final stage of cellular respiration, where electrons are transferred through a series of protein complexes in the mitochondrial membrane to produce ATP.

Where does the Krebs cycle occur, and how is it related to the electron transport chain?

The Krebs cycle occurs in the mitochondrial matrix. It produces 10 NADH and 2 FADH2 molecules, which are essential for the electron transport chain to generate ATP.

What is the role of NADH and FADH2 in the electron transport chain?

NADH and FADH2 donate electrons to the electron transport chain, allowing the transfer of electrons through the protein complexes, which ultimately helps in the production of ATP.

How do the protein complexes in the electron transport chain work?

The protein complexes (Complex I-IV) move electrons through the chain while pumping protons (H+) across the mitochondrial membrane, creating a proton gradient necessary for ATP production.

What are the two transporters associated with the electron transport chain?

The two main electron transporters are Coenzyme Q10 and Cytochrome C. They transport electrons between different protein complexes in the chain.

How is ATP synthesized in the electron transport chain?

ATP is synthesized when protons flow back into the mitochondrial matrix through ATP synthase, using the proton gradient created by the electron transport chain.

How many ATP are produced by NADH and FADH2 in total?

NADH produces 3 ATP per molecule, and FADH2 produces 2 ATP per molecule. In total, 30 ATP are generated from 10 NADH, and 4 ATP from 2 FADH2.

What is the total ATP yield from the entire process of cellular respiration?

The total ATP yield from the entire process of cellular respiration is 38 ATP, though 2 ATP are consumed to transport NADH from the cytoplasm into the mitochondria, reducing the net total to 36 ATP.

Why is there a difference in ATP production between NADH and FADH2?

NADH results in 3 ATP due to the electrons passing through more protein complexes, whereas FADH2 only results in 2 ATP because its electrons enter the electron transport chain later, bypassing some of the protein complexes.

How do the models of electron transport chain differ in ATP production?

The traditional model suggests a total of 38 ATP produced, whereas a newer model may suggest 30 ATP due to adjustments in the efficiency of NADH transportation from the cytoplasm to the mitochondria.