Cellular Respiration and Energy Production

What are the differences between catabolic and anabolic pathways?

Catabolic pathways break down large molecules into smaller ones, producing energy (exergonic), while anabolic pathways build larger molecules from smaller ones, requiring energy (endergonic).

What is a redox reaction?

A redox reaction involves the transfer of electrons from one molecule to another, where the molecule losing electrons is oxidized and the one gaining electrons is reduced.

What is the overall summary reaction for cellular respiration?

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O, which is an example of a redox reaction as it involves the transfer of electrons from glucose to electron carriers.

What are the three main parts of cellular respiration and their locations?

1) Glycolysis (cytoplasm), 2) Pyruvate processing (mitochondrial matrix), 3) Krebs cycle (mitochondrial matrix).

What is the role of NAD+ in cellular respiration?

NAD+ acts as a transport carrier and coenzyme for dehydrogenase enzymes, necessary for glycolysis and other reactions.

How does ATP provide energy for chemical reactions?

ATP activates reactions by transferring a phosphate group to other molecules, making them more reactive.

When and where is ATP produced during cellular respiration?

ATP is produced during glycolysis (cytoplasm), Krebs cycle (matrix), and the electron transport chain (inner membrane), totaling 38 ATP per glucose molecule.

Why is fermentation important in the absence of oxygen?

Fermentation generates NAD+ to allow glycolysis to continue when oxygen is not available.

When are the carbons of glucose oxidized and CO2 produced during respiration?

Carbons are oxidized during pyruvate processing (2 CO2) and the Krebs cycle (4 CO2), totaling 6 CO2.

Describe the fate of carbons in the Krebs cycle.

1) Acetyl-CoA enters, combining with oxaloacetate to form citric acid. 2) Two carbons are released as CO2 through decarboxylation. 3) Remaining carbons regenerate oxaloacetate. 4) High-energy electrons are transferred to NAD+ and FAD, forming NADH and FADH2.

Why is the transfer of electrons down the electron transport chain exergonic?

The stability of electrons increases as they transfer to oxygen, releasing energy and making the process exergonic.

What is the ATP yield from the breakdown of glucose?

Glycolysis: net gain of 2 ATP; Pyruvate processing: no ATP; Krebs cycle: 2 ATP; Electron transport chain: up to 34 ATP; Total: 38 ATP per glucose.

How can other food molecules be oxidized to make ATP?

Fats, proteins, and other carbohydrates can be oxidized in the cellular respiration pathway to produce ATP.

How is the cellular respiration pathway regulated?

Regulated by feedback inhibition, where the product of the pathway inhibits its own production, such as ATP binding to phosphofructokinase.

What is the significance of the phrase 'Leo the lion says GER'?

It helps remember that 'Losing Electrons is Oxidation' (GER) and 'Gaining Electrons is Reduction'.

What is the function of ATP synthase in cellular respiration?

ATP synthase produces ATP during oxidative phosphorylation in the electron transport chain.

What happens during glycolysis?

Glycolysis converts glucose into pyruvate, producing a net gain of 2 ATP and 2 NADH.

What is the purpose of the Krebs cycle?

The Krebs cycle generates high-energy electron carriers (NADH and FADH2) and ATP while releasing CO2.

What role do electron carriers play in cellular respiration?

Electron carriers like NADH and FADH2 transport electrons to the electron transport chain to generate ATP.

What is the significance of oxaloacetate in the Krebs cycle?

Oxaloacetate combines with acetyl-CoA to initiate the Krebs cycle and is regenerated at the end of the cycle.

How does the electron transport chain contribute to ATP production?

It uses the energy released from electron transfers to pump protons, creating a gradient that drives ATP synthesis.

What is substrate-level phosphorylation?

A process of ATP generation that occurs directly in glycolysis and the Krebs cycle, where a phosphate group is transferred to ADP to form ATP.

How does the presence of oxygen affect cellular respiration?

Oxygen is essential for the electron transport chain and allows for the complete oxidation of glucose, maximizing ATP yield.