8D-ETC and Oxidative Phosphorylation

Summary

The electron transport chain (ETC) occurs in the inner mitochondrial membrane, utilizing protein complexes and ATP synthase to produce ATP. NADH and FADH2 donate electrons, powering proton pumps that create a gradient, essential for ATP synthesis. Oxygen serves as the final electron acceptor, forming water and underscoring its critical role in cellular respiration. This process yields a total of 36 ATP molecules from one glucose molecule in eukaryotes, while prokaryotes can generate 38 ATP due to the absence of membrane-bound organelles. Other food molecules, including carbohydrates, fats, and proteins, also contribute to ATP production.

Takeaways

• 😀 The electron transport chain (ETC) occurs in the inner mitochondrial membrane, which is folded into cristae to increase surface area for ATP production.
• 🔋 The ETC utilizes protein complexes and ATP synthase to produce ATP, pumping protons across the membrane to create a gradient.
• 💧 NADH and FADH2 are oxidized in the ETC, with electrons passed through protein complexes, contributing to the formation of ATP.
• ⚡ NADH can produce three ATP molecules, while FADH2 yields two ATP molecules due to differing proton movements.
• 🌍 Eukaryotic cells can yield approximately 36 ATP from one glucose molecule, whereas prokaryotic cells can yield up to 38 ATP.
• 🧬 Glycolysis breaks glucose into two pyruvates, generating two ATP and two NADH molecules that enter the mitochondrion.
• 🍃 In the Krebs cycle, two acetyl CoA molecules produce additional ATP, NADH, and FADH2, contributing to the ETC.
• 💨 Oxygen acts as the final electron acceptor in the ETC, reducing to water; its absence halts ATP production and can lead to death.
• 🔄 The process of oxidative phosphorylation involves the oxidation of NADH and FADH2 to produce ATP through ATP synthase.
• 🥗 Other food molecules, such as polysaccharides, fats, and proteins, can also be utilized in cellular respiration to generate ATP.

Q & A

What is the primary location of the electron transport chain in eukaryotic cells?

The electron transport chain primarily occurs in the inner mitochondrial membrane.

Why are the inner mitochondrial membranes folded into cristae?

The inner mitochondrial membranes are folded into cristae to increase the surface area, which enhances the production of ATP molecules.

What molecules serve as electron donors in the electron transport chain?

NADH and FADH₂ serve as electron donors in the electron transport chain.

How many protons does NADH move across the membrane compared to FADH₂?

NADH moves approximately three protons across the membrane, while FADH₂ moves about two protons.

What is oxidative phosphorylation?

Oxidative phosphorylation is the process of generating ATP through the phosphorylation of ADP, powered by the proton gradient created by the electron transport chain.

What is the net yield of ATP from one glucose molecule in eukaryotic cells?

The total net yield from one glucose molecule in eukaryotic cells is approximately 36 ATP molecules.

What occurs during glycolysis?

During glycolysis, glucose is broken down into two pyruvates, producing two ATP and two NADH molecules.

How does the Krebs cycle contribute to ATP production?

In the Krebs cycle, each acetyl-CoA produces ATP through substrate-level phosphorylation, along with NADH and FADH₂, which enter the electron transport chain.

Why do prokaryotic cells yield more ATP than eukaryotic cells?

Prokaryotic cells yield more ATP because they lack membrane-bound organelles, allowing their electron transport chain to operate directly in the plasma membrane without ATP expenditure to transport NADH.

What other food molecules can be used in cellular respiration apart from glucose?

Apart from glucose, other food molecules used in cellular respiration include polysaccharides, fats (glycerols and fatty acids), and proteins (amino acids).