Lecture 20: Bioenergetics

Flashcards about Bioenergetics.

What are the two main types of metabolic pathways?

Anabolic and catabolic pathways.

What is catabolism?

The breakdown of complex molecules to release energy.

What is anabolism?

The synthesis of complex molecules from smaller ones, requiring energy.

Are catabolic reactions exergonic or endergonic?

Exergonic.

Are anabolic reactions exergonic or endergonic?

Endergonic.

What is the role of ATP and NADPH in metabolism?

They store energy harvested from catabolism to power anabolism.

How are catabolic and anabolic pathways described in terms of molecule flow?

Catabolic pathways are convergent, while anabolic pathways are divergent.

What is the role of Acetyl CoA in metabolism?

It serves as a central molecule that converges from catabolic pathways and diverges into anabolic pathways.

What does ΔG° represent?

Inherent free energy change. It indicates the natural bias of a reaction towards products or reactants.

How can an unfavorable reaction (positive ΔG°) be driven forward?

By increasing reactant concentration or decreasing product concentration.

What is substrate availability in the context of metabolic regulation?

Regulating metabolic reactions through the imbalance of products and reactants.

How can metabolic pathways be regulated?

Through a combination of enzyme regulation and substrate availability.

What is the role of ATP in coupled reactions?

ATP hydrolysis provides energy to drive unfavorable reactions forward.

What are the components of ATP?

Adenine, ribose, and three phosphate groups.

What are the four reasons why ATP hydrolysis is favorable?

Relief of charge repulsion, resonance stabilization, solvation, and increased entropy.

How do ATP, ADP, and AMP act as regulators in metabolic pathways?

They indicate the energy state of the cell and regulate anabolic and catabolic enzymes accordingly.

How is PFK-1 regulated by ATP and AMP?

ATP inhibits PFK-1, while AMP activates it.

What is substrate-level phosphorylation?

The process of forming ATP by transferring a phosphate group from a substrate molecule to ADP.

What type of bond is a thioester, and why is it important in acetyl CoA?

The bond between sulfur and carbonyl. Breaking the bond releases energy.

What are adenylates?

A collective term for ATP, ADP and AMP.

What is the difference between depleted adenylates and fully charged adenylates?

Depleted adenylates (ADP/AMP) indicate a low energy state and ATP indicates a high energy state.