IBDP Cell respiration

ATP

Adenosine triphosphate; the energy currency of the cell, a nucleotide.

Energy currency of the cell

ATP is known as the energy currency of the cell, providing energy for cellular processes.

Catabolic reaction

A process that breaks down molecules, releasing energy, such as the conversion of ATP to ADP.

ATP → ADP + Pi

The reaction that releases energy for cellular processes by breaking the bond between the second and third phosphate.

Compartmentalization of energy

ATP is soluble and stable; cannot cross membranes, keeping energy organized within cells.

Anabolic reactions

Reactions that require energy, for which ATP is needed, such as synthesis of molecules.

Active transport

The process of moving substances across cell membranes, requiring energy from ATP.

Cell respiration

A biochemical process that releases energy from carbon compounds to produce ATP.

Difference between respiration and breathing

Cell respiration is a chemical process; breathing is mechanical ventilation related to gas exchange.

Aerobic respiration

Respiration with oxygen that produces glucose, CO₂, H₂O, and up to 30 ATP per glucose molecule.

Anaerobic respiration

Respiration without oxygen producing less ATP; in yeast: glucose → ethanol + CO₂, in humans: glucose → lactate.

Lactate buildup

Occurs during anaerobic respiration in humans, causing fatigue and requiring oxygen to break down later.

Oxygen debt

The amount of oxygen needed to convert lactate back to pyruvate after anaerobic activity.

Respiration rate measurement

Measured by changes in O₂ or glucose concentration or increases in CO₂ and pH changes.

Respirometer

An instrument that measures O₂ consumption; CO₂ is absorbed chemically, creating negative pressure.

Experimental variables

Factors that can affect respiration rate, including type of organism, temperature, and substrate.

Control variables

Conditions kept constant during an experiment to ensure valid results, such as pressure and substrate.

Heat measurement of respiration

Not reliable due to variability in pressure and temperature; more effective measures are used.

Energy regeneration

ATP is regenerated by adding energy (from processes like respiration and photosynthesis) back to ADP.

ATP yield in aerobic respiration

Up to 30 ATP are produced per glucose molecule in aerobic respiration within mitochondria.

ATP yield in anaerobic respiration

Only 2 ATP are produced per glucose molecule in anaerobic respiration occurring in the cytoplasm.

Strains on energy supply during exercise

Lactate buildup and the need for oxygen indicates temporary inefficiencies of anaerobic processes.

Role of substrates in respiration

Carbohydrates, fats, and proteins can serve as substrates in aerobic respiration for energy production.

Gas exchange process

O₂ enters and CO₂ exits during respiration, linking it to breathing but fundamentally distinct.

Importance of controls in experiments

Essential for ensuring that results from experiments measuring respiration can be trusted and interpreted.