Bioenergetic (notes)

What are the main purposes for which all life requires energy?

Synthesis, reproduction, active transport, movement, temperature control.

What is metabolism?

The totality of an organism's chemical reactions.

What are catabolic pathways?

Pathways that release energy by breaking down complex structures into simpler compounds.

What is an example of catabolic pathways?

Cellular respiration, which is the breakdown of glucose in the presence of oxygen.

What is an anabolic pathway?

A pathway that consumes energy to build complex molecules from simpler ones.

What is potential energy?

Energy that matter possesses because of its location and structure.

Define Gibbs free energy (G).

The amount of energy available to do work (usable energy).

What indicates a spontaneous reaction?

An exergonic reaction proceeds with a net release of free energy and has ΔG < 0.

What is an endergonic reaction?

A reaction that absorbs free energy from its surroundings and is nonspontaneous, with ΔG > 0.

What is activation energy?

The energy required for a reaction to proceed, causing reactant(s) to become contorted and unstable.

What does the first law of thermodynamics state?

The total amount of energy in the universe is constant; energy cannot be created or destroyed.

What do autotrophs do to obtain energy?

They use energy from sunlight or from chemical bonds in inorganic substances to make organic compounds.

What is ATP?

Adenosine triphosphate, the cell's energy shuttle.

How does ATP drive cellular work?

By coupling exergonic processes to drive endergonic ones.

What happens during ATP hydrolysis?

ATP is converted to ADP and a phosphate group, releasing energy.

What is the role of oxygen in the electron transport chain?

Oxygen is the final electron acceptor, enabling continuous ATP production by keeping electrons moving.

What is fermentation?

The breakdown of glucose yielding ATP without O2.

What type of fermentation occurs in human cells during low oxygen availability?

Lactic acid fermentation.

What is produced as a waste product during alcoholic fermentation?

Carbon dioxide (CO2).

What do fermentation processes recycle to allow glycolysis to continue?

NAD+.

What is the efficiency of glycolysis alone or as part of fermentation in capturing energy from glucose?

Not very efficient, capturing only about 2% of the energy available from glucose.

What is the role of enzymes in metabolic reactions?

Enzymes act as catalysts to speed up metabolic reactions by lowering activation energy.

What is the function of coenzymes?

Coenzymes are organic molecules that assist enzymes in catalyzing reactions.

What is glycolysis?

Glycolysis is the process of breaking down glucose into pyruvate, producing a small amount of ATP.

What happens during oxidative phosphorylation?

Oxidative phosphorylation generates ATP through the electron transport chain and chemiosmosis.

How many ATP molecules are produced from one glucose molecule during cellular respiration?

Up to 38 ATP molecules can be produced from one molecule of glucose.

What is the purpose of the Krebs cycle?

The Krebs cycle (citric acid cycle) generates electron carriers (NADH, FADH2) and ATP through the oxidation of acetyl-CoA.

What is substrate-level phosphorylation?

Substrate-level phosphorylation is the direct formation of ATP from ADP during a metabolic reaction.

What are the key differences between aerobic and anaerobic respiration?

Aerobic respiration requires oxygen and produces more ATP, while anaerobic respiration occurs without oxygen and produces less ATP.

What is oxidative stress?

Oxidative stress is an imbalance between free radicals and antioxidants in the body, leading to cellular damage.

What is a metabolic pathway?

A metabolic pathway is a series of enzymatic reactions that convert a substrate into a product.