Metabolism and Energy Flashcards

Unit 2: Metabolic Processes

• Big Ideas:

  • All metabolic processes involve chemical changes and energy conversions.

  • An understanding of metabolic processes enables informed choices regarding personal, societal, and environmental issues.

Lesson 1: Metabolism and Energy

Brainstorming on Glucose and Photosynthesis

• Topics of interest:

  • Glucose and its role in metabolism.

  • Photosynthesis flowchart analysis including references to components like 2-P-Glycerate, Acetate, and Acetyl-CoA.

  • General knowledge of metabolic processes and their complexities.

Overview of Metabolism

• Definition:

  • Metabolism refers to the total sum of all chemical reactions that change/transform matter and energy within cells.

• Function:

  • Living cells serve as mini chemical factories performing thousands of reactions.

Organization of Metabolic Pathways

• Definition of Metabolic Pathway:

  • A sequence of chemical reactions starting with a specific molecule and ending with a product, with each step catalyzed by a specific enzyme.

• Importance of Enzymes:

  • Enzymes are crucial as they allow reactions to occur at a rate sufficient to sustain life.

Types of Metabolic Pathways

• Catabolic Pathways (Catabolism):

  • Involve breaking down large complex molecules (e.g., glucose).

  • Example: Cellular respiration which releases energy.

• Anabolic Pathways (Anabolism):

  • Involve building larger molecules from smaller ones (e.g., protein synthesis from amino acids).

  • Function: Uses energy to construct needed biomolecules.

Forms of Energy

• Free Energy:

  • The capacity to do work (cause change).

• Types of Energy:

  • Kinetic Energy: Energy associated with motion.

  • Potential Energy: Stored energy, convertible to kinetic energy (e.g., a diver on a platform).

  • Chemical Energy: Stored in chemical bonds; represents potential energy.

  • Thermal Energy: Energy related to temperature within a system.

Thermodynamics and Energy Changes

• The Laws of Thermodynamics:

  • First Law: Energy of the universe is constant; energy can neither be created nor destroyed, only transformed.

  • Second Law: As energy transfers occur, entropy (disorder) in the universe tends to increase; usable energy decreases as it transforms into heat.

• Systems Classification:

  • Isolated System: No exchange of energy/matter.

  • Closed System: Exchange of energy but not matter.

  • Open System: Exchange of both energy and matter (e.g., organisms).

Reaction Energy Changes

• Exergonic Reactions:

  • Release free energy (-ΔG); spontaneous processes.

• Endergonic Reactions:

  • Absorb free energy (+ΔG); non-spontaneous.

• Activation Energy: Required to initiate reactions.

ATP and Energy Coupling

• ATP (Adenosine Triphosphate):

  • Acts as the cell’s energy shuttle, composed of ribose, adenosine, and three phosphate groups.

• ATP-ADP Cycle:

  • Energy released from catabolic processes is harnessed by ATP for anabolic processes.

• Renewability: ATP is continually regenerated in cells.

Electron Carriers in Metabolism

• Role in Redox Reactions:

  • NAD+, FAD are key electron carriers, transitioning between oxidized and reduced states (NADH, FADH2) in metabolic pathways.

• Importance: Crucial for transferring electrons, enabling energy transformations in cell metabolism.