Thermochemistry and ATP Metabolism

Vocabulary practice flashcards covering cellular thermodynamics, metabolic reactions, bond energy, activation energy, and the structure and turnover of ATP.

Metabolism

The sum of all chemical reactions occurring in a cell or organism, representing the overall process by which an organism obtains nutrients, extracts energy from them, and uses that energy.

Anabolic Processes

Metabolic pathways that construct complex molecules from simpler ones, such as synthesizing polymers.

Catabolic Processes

Metabolic pathways that break down complex molecules into simpler ones, such as the hydrolysis of polymers.

Chemical Energy

The form of potential energy stored in the covalent bonds between atoms within a molecule that powers life processes.

Chemical Work (Cellular)

The type of cellular work involved in synthesizing molecules required for growth and reproduction.

Transport Work (Cellular)

The type of cellular work that moves substances across membranes, including active transport, endocytosis, and exocytosis.

Mechanical Work (Cellular)

The physical movement carried out by cells and organelles, including muscle contraction, cilia or flagella beating, and organelle movement.

First Law of Thermodynamics

A fundamental law stating that energy cannot be created or destroyed, but can only be converted from one form to another, meaning the total energy of the universe remains constant.

Bond Energy

The amount of energy required to break a chemical bond; a higher bond energy indicates greater chemical stability of the bond and requires more energy to break.

Activation Energy

The initial input of energy required to break the chemical bonds of the reactants to initiate a chemical reaction.

Exergonic (Exothermic) Reaction

A chemical reaction that releases energy because the energy required to break the reactant bonds is less than the energy released when product bonds form.

Endergonic (Endothermic) Reaction

A chemical reaction that absorbs energy because the energy required to break the reactant bonds is greater than the energy released when product bonds form.

Photosynthesis

An endergonic process that utilizes light energy to assemble low-energy molecules ($\text{CO}_2$ and $\text{H}_2\text{O}$) into a higher-energy carbohydrate (glucose, stored as starch).

Cellular Respiration

An exergonic process that breaks down high-energy glucose into smaller molecules ($\text{H}_2\text{O}$ and $\text{CO}_2$) to release energy in the form of $\text{ATP}$.

Molecular Components of ATP

A nucleotide structure composed of one nitrogenous base (adenine), one five-carbon ribose sugar, and three serially bonded phosphate groups.

ATPase

The enzyme that catalyzes the hydrolysis reaction removing a terminal phosphate group from $\text{ATP}$ to form $\text{ADP}$ and inorganic phosphate ($\text{P}_\text{i}$).

Energy of ATP Hydrolysis

The release of $-30.5\,\text{kJ/mol}$ of energy when a phosphate group is cleaved from $\text{ATP}$ to produce $\text{ADP}$ and $\text{P}_\text{i}$, occurring because the phosphate groups require less energy to break than the energy released during product formation.

Enzymatic Activation Energy Reduction

The catalytic action of an enzyme that accelerates a reaction by lowering the required activation energy threshold without changing the overall net energy released between reactants and products.

Cellular ATP Turnover

The rapid dynamic cycle where over $10\text{ million}$ $\text{ATP}$ molecules are consumed and regenerated per second per cell, with a single working muscle cell requiring $600\text{ million}$ $\text{ATP}$ per minute.