BIOENERGETICS: The Body's Energy System

Flashcards covering the core concepts of bioenergetics from the lecture notes, including energy laws, ATP biology, redox chemistry, electron carriers, glycolysis, Krebs cycle, oxidative phosphorylation, and energy regulation.

What is bioenergetics?

The study of energy transformations in living organisms.

What does the First Law of Energy state in living systems?

Energy cannot be created or destroyed; it only changes form.

Give an example of energy conversion in biology.

Plants convert sunlight into stored chemical energy; humans obtain energy by eating plants or animals that ate plants.

What happens to some energy as heat in biological processes?

Some energy is always lost as heat, contributing to body warmth.

What energy source fuels the body when a patient is not eating?

Stored energy from fat and muscle breakdown.

What is entropy in the context of energy?

The tendency for systems to become more disorganized unless energy is expended to maintain order.

How does the body maintain order despite entropy?

By continually using energy to stay organized and function.

What are exergonic reactions?

Energy-releasing reactions that occur spontaneously, such as breaking down food (downhill).

What are endergonic reactions?

Energy-requiring reactions that need energy input to proceed (uphill).

What is energy coupling in metabolism?

The process by which energy released from exergonic reactions powers endergonic reactions.

What is ATP in cellular energy?

Adenosine Triphosphate, the main energy currency of cells.

What happens to ATP during energy use?

ATP donates a phosphate group, becoming ADP.

How is ATP regenerated after use?

ADP is rephosphorylated to ATP using energy from food.

What happens to ATP production during shock or critical illness?

Cells may be unable to make enough ATP, leading to energy shortages.

What is ATP hydrolysis?

The breakdown of ATP to release energy for cellular work.

Which electron carriers pick up electrons from food breakdown?

NADH and FADH2.

Which carrier delivers electrons to build new molecules?

NADPH.

What do NADH and FADH2 do with electrons?

They deliver electrons to the electron transport chain to drive ATP production.

What are the three main stages of glucose metabolism?

Glycolysis, the Citric Acid Cycle (Krebs), and Oxidative Phosphorylation (ETC).

Why is oxygen vital for ATP production?

Oxygen is the final electron acceptor in oxidative phosphorylation, enabling large ATP yields.

What occurs during glycolysis?

Glucose is broken into smaller pieces in the cytoplasm, generating a small amount of ATP and NADH.

Where does the Citric Acid Cycle occur and what does it produce?

In mitochondria; it produces NADH and FADH2 and further metabolizes acetyl-CoA.

What happens during oxidative phosphorylation?

NADH and FADH2 donate electrons to the electron transport chain, producing a large amount of ATP.

How is energy regulation described as a thermostat?

When ATP is abundant, production slows; when ATP is low, production speeds up; hormones regulate storage and use (e.g., insulin and glucagon).

What diseases illustrate energy regulation imbalances?

Diabetes and obesity.

What is the metaphor for ATP's role in energy storage?

ATP is the body's rechargeable energy battery.

What is the relationship between exergonic and endergonic reactions?

Energy from exergonic reactions powers endergonic reactions (coupling).

How do antioxidants relate to redox reactions?

Antioxidants prevent harmful oxidation by neutralizing reactive oxidants.

What happens to energy flow when oxygen is lacking?

Oxidative phosphorylation slows or stops, decreasing ATP production and energy availability.