11.1.1 Recognise the Importance of Homeostasis
Homeostasis is the process by which organisms maintain a stable internal environment despite external changes. Its importance includes:
- Ensures optimal conditions for cellular functions (e.g., enzyme activity, metabolic processes).
- Maintains critical parameters like temperature, pH, water balance, and ion concentrations.
- Prevents damage to cells and organs, enabling survival in varying environments.
- Supports growth, reproduction, and overall health in organisms (e.g., regulating body temperature in humans or water balance in plants).
11.1.2 Discuss Negative Feedback Mechanism
A negative feedback mechanism counteracts changes in a system to restore homeostasis:
- Process: A sensor detects a deviation from the normal range (set point), signals a control center (e.g., brain), which activates an effector to reverse the change.
- Example: Blood glucose regulation:
- High glucose levels → Pancreas releases insulin → Glucose uptake by cells increases → Glucose levels decrease.
- Low glucose levels → Pancreas releases glucagon → Liver releases glucose → Glucose levels increase.
Key Features:
- Stabilizes conditions by opposing the initial change.
- Involves a feedback loop (sensor → control center → effector).
- Common in physiological processes (e.g., temperature, blood pressure regulation).