Cellular Energetics and Thermodynamics

This set of flashcards covers key concepts in cellular energetics and thermodynamics, including enzyme activity, photosynthesis, and cellular respiration.

What is the principle of thermodynamics concerning energy?

Energy cannot be created or destroyed; the universe tends to go towards disorder (entropy increases).

What are endergonic reactions?

Reactions that require energy, where reactants have less energy than products.

Define exergonic reactions.

Reactions that release energy, where reactants have more energy than products.

What is activation energy?

The energy required to transform reactants into the transition state, allowing the reaction to occur.

What is the role of enzymes in chemical reactions?

Enzymes are proteins that catalyze reactions by binding to substrates at their active site.

What happens during enzyme denaturation?

Enzyme function is reduced when its optimal temperature or pH is deviated, altering its tertiary structure.

What is the function of cofactors in enzymatic activity?

Cofactors are additional molecules that assist enzymes in binding to substrates; they can be organic (coenzymes) or inorganic (ions).

How does temperature affect enzyme activity?

Temperature increases enzyme activity up to an optimal point; beyond this, high temperatures can denature the enzyme.

What is competitive inhibition in enzyme regulation?

A molecule blocks the substrate from binding to the active site by occupying it.

What does ATP stand for and what is its role in the cell?

ATP stands for Adenosine Triphosphate and is the energy currency of the cell.

What is noncyclic photophosphorylation?

A process in light reactions that produces ATP and NADPH by transferring electrons through an electron transport chain.

What is the main function of the Calvin cycle in photosynthesis?

To fix carbon dioxide into carbohydrates (glucose) using ATP and NADPH.

What is the final electron acceptor in the electron transport chain during cellular respiration?

Oxygen acts as the final electron acceptor, combining with electrons and protons to form water.

What are the end products of the Krebs cycle?

4 ATP, 10 NADH, and 2 FADH2.

How is ATP synthesized during cellular respiration?

Through the process of chemiosmosis, where H+ ions flow through ATP synthase to combine ADP and P.

What are the products of glycolysis?

2 ATP used, 4 ATP gained, and 2 NADH gained.

What process occurs in anaerobic respiration when oxygen is not available?

Fermentation, resulting in only 2 ATP from glycolysis and regeneration of NAD+.

What is the product of alcoholic fermentation?

Ethanol is produced, regenerating NAD+ from NADH.

What is the product of lactic acid fermentation?

Lactic acid is produced, regenerating NAD+ from NADH.