Questions & explanations
1. Which type of modified root is characteristically swollen in the middle and tapers at both ends, as seen in radish?
- Conical
- Fusiform
- Napiform
- Tuberous
Answer: Fusiform
Fusiform roots are swollen in the middle and taper at both ends, like in radish. Conical roots are broad at the base and taper towards the apex (carrot), napiform are spherical at the base and taper abruptly (turnip), and Tuberous roots are adventitious root modifications (e.g., sweet potato) that are irregularly swollen, distinct from tap root modifications like fusiform, conical, and napiform..
2. Given the floral formula: ⊕ ⚥ K(5) C(5) A5 G(2), which family does the plant belong to?
- Fabaceae
- Solanaceae
- Liliaceae
- Brassicaceae
Answer: Solanaceae
The formula ⊕ (actinomorphic), ⚥ (bisexual), K(5) (5 fused sepals), C(5) (5 fused petals), A5 (5 epipetalous stamens), G(2) (bicarpellary syncarpous superior ovary) is typical of Solanaceae. Fabaceae has zygomorphic, diadelphous stamens; Liliaceae has trimerous, tepals; Brassicaceae has 4 sepals/petals.
3. Which of the following best defines a fruit?
- A mature or ripened ovary containing seeds
- Any structure that develops from the flower
- The swollen base of the pistil
- The fertilized ovule
Answer: A mature or ripened ovary containing seeds
A fruit is botanically defined as a mature or ripened ovary, typically containing seeds. Other options are incorrect: not all flower structures become fruits, the swollen base of the pistil is part of the ovary but not the full definition, and the fertilized ovule develops into a seed, not the fruit.
4. Which of the following floral characters is characteristic of the family Fabaceae?
- Actinomorphic flowers with epipetalous stamens
- Papilionaceous corolla with diadelphous stamens
- Trimerous flowers with perianth of tepals
- Superior ovary with axile placentation
Answer: Papilionaceous corolla with diadelphous stamens
Fabaceae (Leguminosae) is characterized by a papilionaceous corolla (butterfly-shaped) and diadelphous stamens (9+1 arrangement). Other options describe Solanaceae (actinomorphic, epipetalous), Liliaceae (trimerous, tepals), and a mix not specific to Fabaceae.
5. Apple is considered a false fruit because it develops from:
- Ovary alone
- Thalamus along with ovary
- Ovary and calyx
- Receptacle and ovary wall
Answer: Thalamus along with ovary
A false fruit develops from parts of the flower other than the ovary. In apple, the fleshy part is derived from the thalamus (receptacle), and the core is from the ovary. Hence it is a false fruit. Options involving only ovary or calyx are incorrect.
6. In a drupe like mango, the fleshy edible part is derived from which layer of the pericarp?
- Epicarp
- Mesocarp
- Endocarp
- Seed coat
Answer: Mesocarp
In drupes, the pericarp has three layers: epicarp (outer skin), mesocarp (fleshy middle layer), and endocarp (hard inner layer). The edible part of mango is the mesocarp. Epicarp is the peel, endocarp is the hard stone, and seed coat covers the seed.
7. Which of the following is a characteristic floral feature of the family Liliaceae?
- Papilionaceous corolla
- Diadelphous stamens
- Trimerous flowers with perianth of tepals
- Inferior ovary with axile placentation
Answer: Trimerous flowers with perianth of tepals
Liliaceae, a monocot family, has trimerous flowers (parts in threes) and a perianth of tepals (undifferentiated sepals and petals). Papilionaceous corolla and diadelphous stamens are Fabaceae features; Liliaceae has a superior ovary, not inferior.
8. In which type of placentation are the ovules arranged along the fused margins of carpels in a multilocular ovary?
- Marginal
- Axile
- Parietal
- Free central
Answer: Axile
Axile placentation has ovules attached to the central axis where septa meet, forming chambers. Marginal is along the ventral suture of a single carpel, parietal is on the ovary wall, and free central is on a central column without septa.
9. In a typical root, the region responsible for cell division is the:
- Root cap
- Region of meristematic activity
- Region of elongation
- Region of maturation
Answer: Region of meristematic activity
The region of meristematic activity consists of actively dividing cells that give rise to new cells, whereas the root cap protects the tip, elongation region increases cell size, and maturation region differentiates into various tissues.
10. A flower that can be divided into two equal halves by any vertical plane passing through the center is called:
- Zygomorphic
- Asymmetric
- Actinomorphic
- Irregular
Answer: Actinomorphic
Actinomorphic flowers have radial symmetry, meaning they can be divided into equal halves by any vertical plane through the center. Zygomorphic flowers have bilateral symmetry, and asymmetric flowers cannot be divided into equal halves.
11. Which sub-aerial stem modification is found in strawberry and helps in vegetative propagation?
- Runner
- Stolon
- Offset
- Sucker
Answer: Runner
Strawberry propagates through runners, which are slender, prostrate branches that develop roots at nodes. Stolon is similar but arises from the base, offset is found in aquatic plants, and sucker arises from underground parts.
12. Which combination of floral characters is typical of the family Solanaceae?
- Actinomorphic flowers, epipetalous stamens, axile placentation
- Zygomorphic flowers, diadelphous stamens, marginal placentation
- Trimerous flowers, perianth of tepals, axile placentation
- Actinomorphic flowers, epipetalous stamens, basal placentation
Answer: Actinomorphic flowers, epipetalous stamens, axile placentation
Solanaceae has actinomorphic (radially symmetrical) flowers, epipetalous stamens (attached to petals), and axile placentation. Option B describes Fabaceae, option C describes Liliaceae, and option D has incorrect placentation.