What is Dynamic Equilibrium?
- Dynamic equilibrium is a state of balance in which internal conditions are maintained within a narrow range despite external changes.
- It is achieved through continuous adjustments and feedback mechanisms.
Dynamic equilibrium is not a static state; it is a constantly adjusting process that allows organisms to adapt to changes while maintaining stability.
The Role of Biochemical Processes
Biochemical processes are the foundation of dynamic equilibrium. They include:
- Photosynthesis: Converts solar energy into chemical energy stored in glucose.
- Cellular Respiration: Releases energy from glucose to power cellular activities.
- Enzyme Action: Catalyzes reactions that regulate metabolism and energy flow.
Remember that the light-dependent reactions produce the energy carriers (ATP and NADPH) needed for the Calvin Cycle, which does not require light but depends on the products of the light-dependent stage.
The Significance of Photosynthesis
- Energy Storage: Converts solar energy into chemical energy stored in glucose.
- Oxygen Production: Releases oxygen as a by-product, essential for aerobic respiration.
- Carbon Fixation: Incorporates atmospheric CO₂ into organic molecules, supporting life on Earth.
Aerobic respiration is 18 times more efficient than anaerobic respiration, producing 36 ATP per glucose molecule compared to just 2 ATP in anaerobic processes.
Types of Respiration
- Aerobic Respiration: Requires oxygen and produces water, carbon dioxide, and 36 ATP.
- Anaerobic Respiration: Occurs without oxygen, producing less energy and by-products like lactic acid or ethanol.
Think of enzymes as keys that fit specific locks (substrates). The lock-and-key model illustrates how enzymes bind precisely to their substrates to catalyze reactions.
Factors Affecting Enzyme Activity
- Temperature: Enzymes have an optimal temperature (e.g., 37°C in humans). Extreme heat can denature enzymes.
- pH: Most enzymes work best near neutral pH, but some, like pepsin, function in acidic environments.
- Substrate Concentration: Reaction rate increases with substrate concentration until enzymes are saturated.
When studying feedback mechanisms, remember that negative feedback stabilizes systems, while positive feedback amplifies changes until a specific outcome is achieved.
Disease as a Failure of Homeostasis
Causes of Homeostatic Failure
- Pathogens: Viruses, bacteria, fungi, and parasites disrupt normal functions.
- Genetic Disorders: Conditions like sickle cell anemia or diabetes affect homeostasis.
- Environmental Factors: Toxins, poor nutrition, and stress can destabilize systems.
Vaccination is a form of active immunity, where the immune system is trained to recognize and respond to specific pathogens without causing disease.
Body Systems and Homeostasis
Nervous and Endocrine Systems
- Nervous System: Detects stimuli and coordinates rapid responses (e.g., reflexes).
- Endocrine System: Regulates long-term processes like growth and metabolism through hormones.
