Study Notes
Life processes are the essential functions that distinguish living organisms from non-living things. These include movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition, often remembered by the acronym 'MRS. GREN'.
- Movement — the ability of living things to change position or place. Example: A cheetah running fast or plants growing towards sunlight.
- Respiration — the process of releasing energy from food. Example: Animals use oxygen to convert sugar into energy, releasing carbon dioxide.
- Sensitivity — the ability to detect and respond to changes in the environment. Example: Plants bending towards light or animals reacting to sounds.
- Growth — the process of increasing in size and maturing. Example: Tadpoles transforming into frogs.
- Reproduction — the ability to produce new individuals. Example: Plants producing seeds or animals giving birth.
- Excretion — the removal of waste products from the body. Example: Animals exhaling carbon dioxide or plants releasing oxygen.
- Nutrition — obtaining or making food for energy and growth. Example: Plants using photosynthesis to make food from sunlight.
- Virus — non-living agents that replicate by infecting host cells. Example: Viruses using host cells to reproduce.
- Dichotomous Keys — tools used to identify organisms based on a series of choices. Example: Using a key to identify a plant species by its leaf shape.
Exam Tips
Key Definitions to Remember
- Movement: Change of position or place in living organisms.
- Respiration: Process of releasing energy from food.
- Sensitivity: Ability to detect and respond to environmental changes.
- Growth: Increase in size and maturity.
- Reproduction: Production of new individuals.
- Excretion: Removal of waste products.
- Nutrition: Obtaining or making food for energy.
- Virus: Non-living agents that replicate in host cells.
- Dichotomous Key: Tool for identifying organisms through choices.
Common Confusions
- Confusing respiration with breathing.
- Thinking viruses are living organisms.
- Misunderstanding the difference between growth and reproduction.
Typical Exam Questions
- What is respiration? The process of releasing energy from food using oxygen.
- How do viruses reproduce? By taking over a host cell's metabolic pathways.
- What is a dichotomous key used for? To identify organisms based on a series of choices.
What Examiners Usually Test
- Understanding of the seven life processes.
- Differences between living and non-living things.
- Ability to use a dichotomous key for classification.