12.1 A2 Level

Energy

8 flashcards to master this topic

Key Concept Flip

Outline three energy-requiring processes in living organisms.

Answer Flip

1. Active Transport: Moving substances against their concentration gradient. 2. Movement: Muscle contraction requires ATP. 3. Anabolic Reactions: Synthesis of complex molecules like DNA replication and protein synthesis.

Key Concept Flip

Describe three features of ATP that make it suitable as the universal energy currency.

Answer Flip

1. Small, manageable energy packets: Releases energy in small, usable amounts. 2. Readily Hydrolyzed: Phosphate bonds are easily broken to release energy. 3. Renewable: Quickly regenerated from ADP and Pi using energy from respiration or photosynthesis.

Definition Flip

State two cellular locations where ATP is synthesized.

Answer Flip

1. Cytoplasm: Substrate-linked reactions. 2. Mitochondria/Chloroplasts: Chemiosmosis in membranes.

Key Concept Flip

Explain the relative energy values of carbohydrates, lipids, and proteins as respiratory substrates.

Answer Flip

Lipids have the highest energy value due to their higher proportion of C-H bonds, which release more energy upon oxidation. Proteins have a variable energy value, while carbohydrates have the lowest energy value per unit mass.

Definition Flip

Define the Respiratory Quotient (RQ).

Answer Flip

The Respiratory Quotient (RQ) is the ratio of the number of molecules of carbon dioxide produced to the number of molecules of oxygen consumed during respiration. RQ = CO₂ produced / O₂ consumed.

Calculation Flip

Calculate the RQ value for the complete oxidation of glucose (C₆H₁₂O₆).

Answer Flip

The equation is: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O. RQ = CO₂ produced / O₂ consumed = 6/6 = 1.0

Key Concept Flip

Describe the purpose of using KOH or soda lime in a respirometer experiment.

Answer Flip

KOH or soda lime is used to absorb the carbon dioxide produced by the respiring organism (

Example: germinating seeds or invertebrates). This allows for accurate measurement of oxygen consumption as the change in volume is solely due to oxygen uptake.
Key Concept Flip

Explain how a respirometer measures the rate of respiration.

Answer Flip

As the organism respires and consumes oxygen, the volume of gas in the respirometer decreases. This decrease in volume causes the fluid in the manometer to move. The distance the fluid moves in a given time is a measure of the rate of oxygen consumption, and thus, the rate of respiration.

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11.2 Antibodies and vaccination 12.2 Respiration continued