DepEd MELC reviewer for Grade 7 Science, Quarter 2. Master the concepts, tables, and common-mistake warnings below.
1
The Cell
The cell is the basic unit of life. Plant cells have a cell wall and chloroplasts; animal cells do not.
| Part | Function |
|---|---|
| Nucleus | Controls activities |
| Cell membrane | Controls what enters/exits |
| Cytoplasm | Jelly where reactions happen |
| Mitochondria | Powerhouse (energy) |
| Chloroplast (plant) | Photosynthesis |
2
Levels of Organization
Cell → Tissue → Organ → Organ System → Organism
3
Ecosystems
An ecosystem links living (biotic) and non-living (abiotic) factors. Energy flows: producers → consumers → decomposers.
💡 Exam Hack
Arrows in a food chain point in the direction energy FLOWS — from the eaten to the eater.
4
Photosynthesis vs Respiration
| Process | Inputs | Outputs |
|---|---|---|
| Photosynthesis | CO₂ + water + light | glucose + O₂ |
| Respiration | glucose + O₂ | energy + CO₂ + water |
💡 Exam Hack
They are opposites — photosynthesis stores energy, respiration releases it.
📌 Quick Recap — Master These
Before your test, make sure you can confidently do each of the following:
- Explain and apply The Cell.
- Explain and apply Levels of Organization.
- Explain and apply Ecosystems.
- Explain and apply Photosynthesis vs Respiration.
Re-read any section above where you hesitate, then try the worked example again without looking.