H. Give Reasons for the Following
Q1. Leaves of some desert plants are reduced to prickly structures.
To reduce water loss through transpiration (since deserts have very little water).
Q2. The leaves of the pea plant are modified into tendrils.
To help the plant climb and support itself.
Q3. Leaves of some plants are modified to digest insects.
To get nutrients (like nitrogen) from insects when the soil is poor.
Q4. Leaves contribute to the water cycle.
They release water vapor into the air through transpiration.
Q5. Stems are negatively geotropic.
They grow away from gravity (upwards) towards sunlight for photosynthesis.
I. Explain the Following Terms
i. Reticulate venation – Veins form a net-like pattern (e.g., mango leaf).
ii. Petiole – The stalk that connects the leaf to the stem.
iii. Simple leaf – A single, undivided leaf (e.g., banana leaf).
iv. Transpiration – The process of water loss from leaves as vapor.
v. Leaf spines – Sharp, pointed leaves (e.g., cactus) to reduce water loss.
J. Differentiate Between the Following
| 1. Root system vs. Shoot system |
| Root – Grows underground, absorbs water. |
| Shoot – Grows above ground, includes stems/leaves. |
| 2. Simple leaf vs. Compound leaf |
| Simple – Single blade (e.g., peepal). |
| Compound – Many leaflets (e.g., neem). |
| 3. Parallel vs. Reticulate venation |
| Parallel – Veins run side by side (e.g., grass). |
| Reticulate – Veins form a network (e.g., rose). |
| 4. Alternate vs. Opposite leaf arrangement |
| Alternate – Single leaf per node (e.g., sunflower). |
| Opposite – Two leaves per node (e.g., guava). |
| 5. Leaf Margin vs. Leaf Midrib |
| Margin – The edge of the leaf (smooth/toothed). |
| Midrib – The thick central vein. |
K. Short Answer Questions
1. List the Parts of a typical leaf:
– Lamina (blade), petiole, midrib, veins.
2. State the Functions of a leaf
– Photosynthesis, transpiration, gas exchange (oxygen & CO₂).
3. What is the function of fleshy leaves in an onion?
Fleshy leaves in an onion: Store food and water.
4. How will you identify a monocot plant based on the root system and venation pattern?
Identifying a monocot:
– Fibrous roots + parallel venation (e.g., maize).
1. Root System:
Monocot Root:
Fibrous root system – Thin, branching roots of similar size, spreading horizontally (e.g., grass, maize, wheat).
No main taproot – Roots arise directly from the stem base.
2. Leaf Venation Pattern:
Monocot Leaves:
Parallel venation – Veins run parallel to each other from the base to the tip (e.g., banana, lily, bamboo).
Key Differences from Dicots:
| Feature | Monocot Plants | Dicot Plants |
| Root System | Fibrous (no taproot) | Taproot system (main root) |
| Venation | Parallel veins | Reticulate (net-like) veins |
Example: A corn plant (monocot) has fibrous roots and parallel-veined leaves, while a bean plant dicot has a taproot and reticulate venation.
- The part of the Pitcher plant leaf are modified to trap insects. Explain
Answer. The pitcher plant has modified leaves that form pitcher-shaped traps to catch insects. The leaf’s tip develops into a colorful, slippery lid with nectar glands to attract prey. Once inside, downward-pointing hairs and digestive enzymes prevent escape, allowing the plant to absorb nutrients from the trapped insects.
L. Long Answer Questions
Q1. State the Characteristics of root and the shoot:
Answer. Root Characteristics:
- Grows underground (geotropic) and away from light (negatively phototropic).
- Anchors the plant and absorbs water/minerals via root hairs.
- Lacks nodes, leaves, or chlorophyll.
- Types: Taproot (dicots) or fibrous (monocots).
Shoot Characteristics:
- Grows above ground (positively phototropic) toward light.
- Comprises stem, leaves, flowers, and buds.
- Conducts photosynthesis (leaves) and transports nutrients (stem).
- Exhibits nodes and internodes; may have thorns or tendrils for support
Q2. Explain the mode of reproduction in Bryophyllum
Answer. Reproduction in Bryophyllum occurs vegetatively through leaf margins, where adventitious buds (epiphyllous buds) develop into new plantlets. When the leaf falls or contacts moist soil, these plantlets take root and grow into independent plants. This asexual reproduction ensures rapid propagation without seeds. Bryophyllum can also reproduce sexually via flowers, but vegetative reproduction is more common due to its efficiency in favorable conditions.
Q4. Explain the different types of leaf modification.
Leaf modifications:
– Spines (cactus) – Reduce water loss.
– Tendrils (pea) – Support climbing.
– Insectivorous (pitcher plant) – Traps insects.
– Storage (onion) – Stores food/water.
Q5. Explain different types of Leaf arrangements in plants:
Answer. Different types of Leaf arrangements in plants are as below:
– Alternate – Single leaf per node.
– Opposite – Two leaves per node.
– Whorled – Three or more leaves per node.
Q6. Describe an activity to demonstrate photosynthesis:
1. Place a potted plant in sunlight for hours.
2. Test a leaf with iodine – turns blue-black, proving starch (food) is made.