Exercises

1. Complete the following table:

Feature	Photosynthesis	Respiration
Raw materials	CO2 and Water	Glucose and Oxygen
Products	Glucose and Oxygen	CO2, Water, and Energy
Word equation	CO2 + H2O --(Sun)→ Glucose + O2	Glucose + O2 → CO2 + H2O + Energy
Importance	Synthesizes food and releases O2	Releases energy for growth

2. Imagine a situation where all photosynthetic organisms disappeared. What would be the impact?

All animals (including humans) would eventually die. Photosynthesis is the primary source of food for almost all living beings (directly or indirectly).
The level of oxygen in the atmosphere would deplete rapidly as it is not being replenished, while CO2 levels would rise dangerously, leading to a total collapse of the biosphere.

3. A potato slice shows starch with iodine. Where does it come from?

Source: The starch is synthesized in the leaves of the potato plant through photosynthesis.
Path: The prepared food (glucose) is converted to sucrose and transported through the phloem to the underground tubers (potatoes), where it is stored as starch.

4. Does the broad and flat structure of leaves make plants more efficient? Justify.

Yes. A broad and flat surface increases the area available to capture maximum sunlight and provides more space for stomata to allow efficient gas exchange.

5. X + Y → Carbon dioxide + Z + Energy. Stand for:

6. Krishna's experiment (Sunlight vs. Dark):

(i) Idea: Testing whether sunlight is essential for starch production.
(ii) Differences: The plant in sunlight remains healthy and green; the one in the dark may become pale and weak over time.
(iii) Confirmation: Only the leaves of the plant kept in sunlight will give a positive blue-black result with iodine.

7. Vani's experiment (CO2 essentiality):

8. Ananya's experiment with Snail (A), Plant (B), Both (C), Water (D):

Investigation: She wants to find out the relationship between CO2 production (respiration) and CO2 consumption (photosynthesis).
Results: Tube A will have high CO2 (turns indicator yellow). Tube B will have low CO2 (in light). Tube C will show a balance because the plant consumes the CO2 released by the snail.

9. Design an experiment for water transport speed (Warm vs. Cold):

Place two similar twigs in tumblers with red ink.
Keep one in a warm area and the other in a cold area (refrigerator).
Observe which one shows the red color moving up the stem/leaves faster. (Warmth usually increases the rate).

10. Photosynthesis and respiration are essential to maintain balance. Discuss.

Photosynthesis consumes CO2 and releases O2.
Respiration consumes O2 and releases CO2.
Together, they maintain a stable atmospheric concentration of these gases, ensuring life can continue on Earth.

Life Processes in Plants - Exercises