Photosynthesis Respiration in 5 Minutes — Free Quick Revision
Learn Photosynthesis Respiration in about 5 minutes — a free bite-sized module with a clear explanation, a worked example and a quick quiz for Indian students.
TL;DR: Learn Photosynthesis Respiration in about 5 minutes — a free bite-sized module with a clear explanation, a worked example and a quick quiz for Indian…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Photosynthesis captures solar energy into glucose. Respiration releases that energy for the plant to use. They're almost opposite.
Biology · Class 10 · about 6 minutes
The Idea
Photosynthesis and Respiration are complementary processes that manage energy in plants.
Photosynthesis (in chloroplasts during the day): - 6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂ - Converts light energy into chemical energy (glucose). - Produces oxygen as a byproduct.
Respiration (in mitochondria, day and night): - C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy (ATP) - Breaks down glucose to release energy the plant needs for growth, transport, and cellular work. - Produces CO₂ and water.
Key comparison: - Photosynthesis: energy input (sun) → energy storage (glucose) - Respiration: energy release (glucose) → energy for work (ATP) - Equations are nearly opposites (just reversed).
Net result: A plant makes more glucose than it respires, so it grows. The excess glucose becomes fruits, seeds, and stored starch.
Both processes are essential: no photosynthesis = no food; no respiration = no energy to use that food.
Worked Example: Why Do Plants Respire at Night?
Problem. Plants cannot photosynthesize at night (no light), but they still respire. Why?
Solution.
Even in darkness, a plant's cells need energy for: - Growth (cell division, protein synthesis) - Transport (moving minerals, sugars through phloem) - Maintenance (repairing damaged cells) - Reproduction (flower and seed production)
The plant breaks down stored glucose via respiration to release ATP, the energy currency. This ATP fuels all these activities.
During the day, photosynthesis produces more glucose than respiration consumes, so the plant builds reserves. At night, it lives off these reserves.
Quick Quiz
Answer each one before reading the explanation beneath it.
1. Which process requires light energy?
- Both photosynthesis and respiration
- Only photosynthesis — correct
- Only respiration
- Neither process requires light
Only photosynthesis
2. If a plant photosynthesizes 10 kg of glucose but respires 6 kg, what happens to the remaining 4 kg?
- It is released as oxygen
- It is stored in the plant (growth, seeds, fruits) — correct
- It is lost as heat
- It becomes water
It is stored in the plant (growth, seeds, fruits)
3. The oxygen produced in photosynthesis comes from ___.
- CO₂ in the air
- Water (H₂O) — correct
- Glucose
- The plant's cells
Water (H₂O)
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