Summary
In biology, organisation refers to the structured levels within living organisms, from cells to systems, each with specific roles. The digestive system breaks down food into nutrients using organs like the stomach and enzymes such as pepsin. The respiratory system involves gas exchange in the lungs, facilitated by structures like alveoli. The cardiovascular system circulates blood through the heart and vessels, delivering oxygen and nutrients. Health and disease encompass factors affecting well-being, including communicable and non-communicable diseases. Plant tissues, organs, and systems involve structures like xylem and phloem for transport and leaves for photosynthesis.
- Cells — Basic functional and structural units in a living organism Example: Red blood cells transport oxygen.
- Tissues — Groups of cells of similar structure working together to perform the same function Example: Muscle tissue enables movement.
- Organs — Made from different tissues working together to perform specific functions Example: The heart pumps blood.
- Organ Systems — Groups of organs with related functions, working together to perform body functions Example: The digestive system processes food.
- Enzymes — Proteins that function as biological catalysts, speeding up reactions without being consumed Example: Amylase breaks down starch into sugars.
- Transpiration — The process of water movement through a plant and its evaporation from aerial parts Example: Water vapor exits through stomata in leaves.
Exam Tips
Key Definitions to Remember
- Cells: Basic units of life
- Tissues: Groups of similar cells
- Organs: Structures with specific functions
- Organ Systems: Groups of organs working together
- Enzymes: Biological catalysts
- Transpiration: Water movement in plants
Common Confusions
- Difference between tissues and organs
- Role of enzymes in digestion
- Transpiration vs. transpiration pull
Typical Exam Questions
- What is the function of the stomach? The stomach breaks down proteins using enzymes like pepsin.
- How do enzymes work? Enzymes speed up chemical reactions without being consumed.
- What is the role of xylem in plants? Xylem transports water and minerals from roots to leaves.
What Examiners Usually Test
- Understanding of levels of organisation
- Functions of different organ systems
- Effects of temperature and pH on enzyme activity
- Processes of transpiration and translocation in plants