Biology - Cells | 2

Exergonic Reactions

Exergonic Reactions

Reactions that release energy, often in the form of heat, and have a negative change in free energy.

Endergonic Reactions

Reactions that require energy input to proceed, resulting in a positive change in free energy.

Potential Energy

Energy stored in an object due to its position or arrangement, which can be converted to kinetic energy.

Kinetic Energy

Energy of motion, which can be transferred to perform work.

1st Law of Thermodynamics

Energy cannot be created or destroyed, only transformed from one form to another.

2nd Law of Thermodynamics

In any energy transfer, the total entropy of a system and its surroundings always increases, leading to energy dispersal.

ATP/ADP Cycle

The process by which cells store energy in ATP and release it by converting ATP to ADP and inorganic phosphate.

Enzymes

Biological catalysts that speed up metabolic reactions by lowering the activation energy required for the reaction to occur.

Active Site

The specific region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Substrate

The reactant molecule upon which an enzyme acts.

Reactants

The starting materials in a chemical reaction that are transformed into products.

Products

The substances formed as a result of a chemical reaction.

Mitochondria

Organelles that facilitate aerobic cellular respiration by providing a site for the Krebs cycle and oxidative phosphorylation.

Redox Reactions

Reactions involving the transfer of electrons, where one substance is oxidized (loses electrons) and another is reduced (gains electrons).

Electron Carriers

Molecules that transport electrons during cellular respiration, facilitating energy transfer.

Glycolysis

The first stage of cellular respiration occurring in the cytoplasm, converting glucose into pyruvate, producing a net gain of 2 ATP and involving NADH as an electron carrier.

Pyruvate Oxidation

The second stage occurring in the mitochondria, converting pyruvate into acetyl-CoA, producing CO2 and NADH, with no ATP gain.

Krebs Cycle

The third stage occurring in the mitochondrial matrix, producing ATP, NADH, FADH2, and CO2 from acetyl-CoA.

Oxidative Phosphorylation

The final stage occurring in the inner mitochondrial membrane, producing the majority of ATP through electron transport and chemiosmosis.

Alcohol Fermentation

An anaerobic process converting glucose into ethanol and CO2, producing 2 ATP.

Lactic Acid Fermentation

An anaerobic process converting glucose into lactic acid, also producing 2 ATP.

Leaf Structures

Structures such as stomata, chloroplasts, and mesophyll cells that are critical for photosynthesis.

Chloroplast

The organelle that captures light energy and converts it into chemical energy through photosynthesis.

Light Reactions

The first stage of photosynthesis occurring in the thylakoid membranes, producing ATP and NADPH from light energy and water.

Calvin Cycle

The second stage of photosynthesis occurring in the stroma, using ATP and NADPH to convert CO2 into glucose.

Factors Impacting Photosynthesis

Light intensity, carbon dioxide concentration, temperature, and water availability that affect the rate of photosynthesis.

Relationship Between Photosynthesis and Cellular Respiration

Photosynthesis converts light energy into chemical energy stored in glucose, while cellular respiration breaks down glucose to release energy for cellular activities.