Biology Definitions:
1. **Cell**:
The basic structural and functional unit of all living organisms.
- eg : Diagram of a plant and animal cell showing organelles.
2. **Photosynthesis**:
The process by which green plants use sunlight to convert carbon dioxide and
water into
e.g : Equation of photosynthesis (6 CO2 + 6 H2O → C6H12O6 + 6
O2).
3. **Enzyme**:
A biological catalyst that speeds up chemical reactions in living organisms.
eg: Diagram showing the enzyme-substrate complex model.
4. **Mitosis**:
A type of cell division that results in two daughter cells, identical to the parent
cell.
- **Illustration**: Phases of mitosis (prophase, metaphase, anaphase,
telophase).
5. **Ecosystem**
A biological community of interacting organisms and their physical environment.
- **Illustration**: Food web or cycle diagram showing energy flow.
Chemistry Definitions:
6. **Atom**:
The smallest unit of an element that retains the properties of that element.
- **Illustration**: Diagram of an atom showing protons, neutrons, and
electrons.
7. **Molecule**:
A group of atoms bonded together representing the smallest fundamental unit
of a chemical compound.
- **Illustration**: Water molecule (H2O) structure.
8. **pH**:
A scale used to determine the acidity or alkalinity of a solution.
- **Illustration**: pH scale from 0 (acidic) to 14 (alkaline).
9. **Chemical Reaction**:
A process where substances (reactants) are transformed into new substances
(products).
- **Illustration**: Simple chemical reaction equation (e.g., Na + Cl → NaCl).
10. **Ionic Bond**:
A type of chemical bond formed through the transfer of electrons from one
atom to another.
- **Illustration**: Diagram showing ion formation (e.g. Na+ and Cl-).
Physics Definitions:
11. **Force**:
A push or pull on an object that can cause it to accelerate.
- **Illustration**: Diagram showing force vectors acting on an object.
12. **Energy**:
The capacity to do work. Common forms include kinetic, potential, thermal, etc.
- **Illustration**: Energy transformation diagram (e.g., potential to kinetic
energy).
13. **Acceleration**:
The rate of change of velocity of an object.
- **Illustration**: Graph showing velocity vs. time with a slope indicating
acceleration.
14. **Wavelength**:
The distance between successive crests of a wave, typically used in relation to
sound and light waves.
- **Illustration**: Diagram of a wave showing crest, trough, and wavelength.
15. **Conduction**:
The transfer of heat through a material without the movement of the material
itself.
- **Illustration**: Diagram showing heat transfer in a metal rod.
### General Scientific Definitions:
16. **Hypothesis**:
A proposed explanation for a phenomenon that can be tested through
experiments.
17. **Theory**:
A well-substantiated explanation of some aspect of the natural world based on
a body of evidence.
18. **Experiment**:
A scientific procedure undertaken to test a hypothesis.
19. **Observation**:
The act of watching or monitoring phenomena to gather data.
### Study Tips:
- **Diagrams**: Make sure to draw and label diagrams as you study to
reinforce visual learning.
- **Flashcards**: Create flashcards with definitions on one side and relevant
illustrations or examples on the other.
- **Group Study**: Discuss concepts with peers to enhance understanding and
retention.
By familiarizing yourself with these definitions, you’
ll have a solid foundation in
the key concepts of the ZIMSEC Combined Science syllabus. Make sure to
practice with real diagrams and perhaps consult your textbooks for visual
reinforcement!