Biology MCQs
Topic Notes: Biology
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
221
What is the typical percentage of the leaf surface area occupied by stomata?
Answer:
1 – 2%
Stomata are microscopic pores found on the epidermis of leaves, stems, and other plant organs. While they are crucial for gas exchange and transpiration, they occupy a relatively small fraction of the total leaf surface area, typically estimated to be between 1% and 2% in most plant species.
222
Which of the following terms describes the enlarged, fleshy portion of an underground stem?
Answer:
tubers
A tuber is a modified, thickened underground stem that serves as a storage organ for nutrients, such as starch, in plants. These structures allow the plant to survive adverse conditions and facilitate vegetative propagation. Examples include potatoes, which develop from swollen stolons or rhizomes.
223
Which category of plant tissues is subdivided into simple and complex groups?
Answer:
Permanent
Permanent tissues in plants are those that have completed their growth and differentiation. They are classified into simple tissues, which consist of a single type of cell (e.g., parenchyma, collenchyma), and complex tissues, which are composed of multiple cell types working together (e.g., xylem and phloem).
224
Which type of connective tissue is typically found covering the articular surfaces at the ends of long bones?
Answer:
hyaline cartilage
Hyaline cartilage is the most abundant type of cartilage in the human body and is specifically found on the articular surfaces of bones within synovial joints. Its smooth, glassy appearance and resilient matrix provide a low-friction surface that facilitates joint movement and absorbs shock, protecting the underlying bone tissue from mechanical wear and tear.
225
Which simple plant tissue is primarily composed of parenchyma cells?
Answer:
ground tissues
Ground tissue in plants is composed primarily of parenchyma cells, which are versatile, thin-walled cells involved in photosynthesis, storage, and secretion. Ground tissue makes up the bulk of the plant body, filling the space between the dermal and vascular tissues.
226
Which of the following vegetables is characterized by an exceptionally high water content, typically exceeding 90%?
Answer:
Lady finger (okra)
Okra, commonly known as lady finger, is a nutrient-dense vegetable that consists of over 90% water by weight. This high water content contributes to its low caloric density and makes it a hydrating food source, while its mucilaginous texture is a result of soluble fiber content.
227
Which of the following structural components is absent in hyaline cartilage?
Answer:
Blood capillaries
Hyaline cartilage is a specialized connective tissue that provides structural support and flexibility. While it contains chondrocytes embedded within lacunae and a matrix of collagen fibers, it is avascular. This means it lacks blood capillaries, relying entirely on diffusion from the surrounding perichondrium to obtain nutrients and oxygen, which limits its capacity for repair.
228
What is the classification of the small, pore-like openings found on the stems of woody plants?
Answer:
lenticels
Lenticels are porous tissues consisting of cells with large intercellular spaces in the periderm of the secondarily thickened stems and roots of woody plants. They function as specialized pores that facilitate gas exchange between the internal tissues and the external atmosphere.
229
What is the botanical term for the enlarged, fleshy portion of an underground stem?
Answer:
stem tubers
A stem tuber is a modified, thickened underground stem that serves as a storage organ for nutrients, particularly starch. These structures, such as those found in potatoes, allow the plant to survive adverse environmental conditions and provide energy for new growth during the next growing season.
230
In which anatomical regions of the human body is stratified squamous epithelium typically found?
Answer:
mouth and esophagus
Stratified squamous epithelium is a tissue composed of multiple layers of cells, providing protection against abrasion. It is found in areas subject to significant mechanical stress, such as the lining of the mouth, esophagus, and the skin surface.