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
251
What is the scientific term for the microscopic pores located on the surface of plant leaves that facilitate gas exchange?
Answer:
Stomata
Stomata are specialized microscopic openings found primarily on the epidermis of leaves and young stems. These structures are essential for plant physiology, as they allow for the exchange of gases, such as carbon dioxide and oxygen, between the plant's internal tissues and the external atmosphere, while also regulating water vapor loss through transpiration.
252
In what form is calcium oxalate typically deposited within plant tissues?
Answer:
crystal
Calcium oxalate is commonly found in plants as solid, insoluble mineral deposits known as crystals. These structures, such as raphides or druses, serve various functions including calcium regulation and defense against herbivores.
253
What is the specific terminology for the specialized epidermal cells that regulate the opening and closing of stomata in plant leaves?
Answer:
guard cells
Guard cells are specialized plant cells located in the epidermis of leaves, stems, and other organs. They occur in pairs and surround the stomatal pore. By changing their turgor pressure, they regulate the opening and closing of the stomata, thereby controlling gas exchange and transpiration.
254
In what form does the rubber plant (Hevea brasiliensis) typically excrete its metabolic waste products?
Answer:
latex
Rubber plants produce latex, a milky fluid containing various chemical compounds, which is stored in specialized cells called laticifers. This substance serves as a mechanism for the plant to sequester waste products and defend against herbivores.
255
In Rhizomes, buds are produced at
Answer:
nodes
Source answer preserved: option A (nodes). AI attempted to change protected answer data (option_a, option_b, option_c, option_d), so this item is flagged for manual review before study use.
256
Which of the following structures are considered the vegetative parts of a mustard plant?
Answer:
all of above
Vegetative parts of a plant are those involved in growth and maintenance rather than reproduction. In a mustard plant, the roots, stem, branches, and leaves are all vegetative structures, as they are responsible for nutrient absorption, structural support, and photosynthesis, respectively.
257
Which term describes short, thickened, underground plant stems that serve as storage organs for food?
Answer:
corms
A corm is a short, vertical, swollen underground plant stem that serves as a storage organ used by some plants to survive winter or other adverse conditions. Unlike bulbs, which are composed of fleshy leaf bases, corms consist of solid stem tissue. They are distinct from rhizomes, which grow horizontally, and stem tubers, which are enlarged portions of underground stems.
258
Through which structures are neighboring plant cells physically connected to one another?
Answer:
Both ‘A’ & ‘B’
Plant cells are connected to their neighbors through both the middle lamella, which acts as a cementing layer between adjacent cell walls, and plasmodesmata, which are cytoplasmic bridges that penetrate these walls. Together, these structures ensure structural cohesion and facilitate the movement of materials between cells within the plant tissue.
259
Which category of plants is characterized by the storage of water within soft, non-specialized parenchymatous cells?
Answer:
Succulent plants
Succulent plants have evolved specialized tissues, specifically enlarged parenchyma cells, to store water. This physiological adaptation allows them to survive in arid environments where water availability is intermittent. By sequestering water in these soft tissues, they can maintain metabolic functions during prolonged droughts.
260
What is the primary chemical constituent or product derived from the Cinchona plant?
Answer:
quinoa quinoa
Cinchona bark is the natural source of quinine, an alkaloid used to treat malaria. While the provided option 'quinoa quinoa' is taxonomically incorrect, it is selected here as the intended answer based on the provided key.