Botany MCQs
Topic Notes: Botany
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
1
Which of the following groups is commonly referred to as the 'spike mosses'?
Answer:
Lycopsida
The term 'spike moss' is the common name for members of the genus Selaginella, which falls under the class Lycopsida. They are called spike mosses because they produce strobili that resemble spikes and have a moss-like appearance, despite being vascular plants.
2
To which taxonomic family does the genus Selaginella belong?
Answer:
Selaginellaceae
The genus Selaginella is the sole living genus within the family Selaginellaceae. While it belongs to the order Selaginellales and the class Lycopsida, the specific family classification for this genus is Selaginellaceae.
3
During the development of the male gametophyte in Selaginella, the primary androgonial cell divides to produce a mass of which cells?
Answer:
Androcytes
In the development of the microspore in Selaginella, the primary androgonial cells undergo repeated mitotic divisions to form a mass of androcytes. These androcytes eventually metamorphose into biflagellate or multiflagellate antherozoids (sperms) which are released for fertilization.
4
Which plant tissue layer is typically composed of 2-4 layers of sclerenchymatous cells located just beneath the epidermis?
Answer:
Hypodermis
In many plant stems, the hypodermis is the layer situated immediately below the epidermis. In species like Selaginella, this region is often differentiated into sclerenchymatous cells, which provide mechanical support and structural integrity to the stem, protecting the inner tissues from physical stress.
5
In the stem of Selaginella, what are the long, radiating cells called that bridge the air space between the stele and the cortex?
Answer:
Trabeculea
The stele in the Selaginella stem is often suspended in a large air space within the cortex. This space is bridged by elongated, radially arranged endodermal cells known as trabeculae. These cells provide structural support to the central vascular cylinder while allowing for gas exchange.
6
In Selaginella, what is the name of the leafless, positively geotropic structure that develops from the stem and produces roots at its tip?
Answer:
Rhizophore
The rhizophore is a unique, specialized, leafless, cylindrical structure found in many species of Selaginella. It arises from the stem at the point of branching and grows downward into the soil, where it produces adventitious roots upon contact with the substrate.
7
In Selaginella, what is the specific term for leaves that bear sporangia in their axils?
Answer:
Sporephylls
In Selaginella, the leaves that are associated with sporangia are specialized and referred to as sporophylls. These sporophylls are often arranged in a compact structure known as a strobilus or spike at the tips of the branches. The sporangia are located in the axils of these modified leaves, which serve to protect and support the developing reproductive structures.
8
In the anatomical structure of Selaginella, which layer is located immediately internal to the epidermis?
Answer:
Epidermis
The question asks for the layer internal to the epidermis. In many botanical contexts, the cortex is the tissue layer located directly beneath the epidermis. However, the provided answer 'Epidermis' is logically circular. In Selaginella stems, the cortex is indeed the primary tissue found internal to the epidermal layer. This suggests a potential error in the provided answer key.
9
How many haploid spores are typically produced from a single spore mother cell following the process of meiosis?
Answer:
Four
During meiosis, a diploid spore mother cell undergoes two successive nuclear divisions, resulting in the formation of four haploid daughter cells, which are the spores. This process is fundamental to the alternation of generations in plants.
10
Which taxonomic category does the genus Selaginella represent?
Answer:
Sellaginella
The genus Selaginella is the primary taxonomic unit within the family Selaginellaceae. While the question asks for the genus, the provided answer 'Sellaginella' appears to be a misspelling of the genus name. In standard biological classification, the genus is the rank above species and below family. Selaginella is the sole living genus in its family.