Problem 92 - Objective Biology for NEET

Question

Stomata helps in (a) Transpiration (b) Exchange of gases (c) Both (a) and (b) (d) None of these

Step-by-Step Solution

Answer

The correct answer is option (c) Both (a) and (b)

Step 1: Understanding the function of Stomata

Stomata are microscopic pores found on the epidermis of plants, more significantly on the outer skin layer of the leaves. They are surrounded by guard cells that help in regulating their opening and closing.

Step 2: Corresponding the options with the functions

Option (a) says transpiration, which is the process of water movement through a plant and its evaporation from aerial parts, such as leaves. Stomata play a vital role in this process, as water vapor is released into the atmosphere through these pores. So, the first option can be considered correct. \n\nOption (b) refers to the exchange of gases. Indeed, stomata are the primary sites for gas exchange in plants, allowing the entry of carbon dioxide (required for photosynthesis) and exit of oxygen (a by-product of photosynthesis). Therefore, this option is also correct

Step 3: Finalizing the correct option

Based on the above analysis, it can be deduced that both the functions - transpiration and exchange of gases - are performed by stomata. Hence, the correct answer would be option (c) Both (a) and (b). Option (d) becomes automatically incorrect.

Key Concepts

Transpiration

Transpiration is a crucial physiological process in plants where water is transported from the roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. Think of transpiration as the plant's version of sweating. This process is essential for several reasons:

• Maintaining nutrient uptake: As water evaporates from the leaves, it creates a negative pressure that pulls more water up through the plant from the roots, bringing essential nutrients along with it.
• Cooling: Similar to how sweat cools our bodies, the evaporation of water from the plant's surface cools the plant on hot days.
• Turgor pressure: It helps in maintaining the turgor pressure of cells which is vital for keeping the plants erect and stable.

Stomata are central to this process, as they control the loss of water vapor from the plant leaves into the environment. Understanding the mechanism of stomata's opening and closing can reveal how plants balance the need to conserve water while allowing for adequate gas exchange.

Gas exchange in plants

Gas exchange in plants is akin to breathing in animals but occurs through diffusion rather than an active respiratory system. Stomata, the small openings on leaves, serve as the primary gatekeepers for this exchange, performing two essential functions:

• Photosynthesis: They admit carbon dioxide (CO₂) into the plant's internal structure for photosynthesis—the process of converting light energy to chemical energy.
• Respiration: They release oxygen (O₂), the by-product of photosynthesis, back into the atmosphere.

This trade-off is carefully controlled, as plants need to minimize water loss without hindering their ability to synthesize food. The regulation of stomatal opening depends on environmental conditions and internal signals, showing the intricate adaptive strategies plants have developed to survive.

Plant physiology

Plant physiology deals with how various parts of plants function, both individually and collectively. It encompasses a wide array of biological processes, including but not limited to:

• Photosynthesis: The process by which green plants use sunlight to synthesize foods with carbon dioxide and water.
• Mineral absorption: Roots absorb minerals and water from the soil which are transported to different parts of the plant.
• Growth: Plant hormones like auxins and gibberellins regulate the growth and development of a plant's organs.
• Stress response: Plants have mechanisms to protect themselves from various stresses such as drought, flooding, and salinity.

Stomata are a window into plant physiology, as they are critical for transpiration and gas exchange—processes fundamental to plant health and survival. Understanding how stomata function is essential for the study of plants' adaptive mechanisms and overall well-being.

NEET Biology

NEET (National Eligibility cum Entrance Test) is a prominent pre-medical entrance examination in India for students aspiring to enter various medical fields. Biology is a significant part of this exam, as it tests knowledge in diverse areas such as genetics, ecology, human physiology, and botany, which includes plant physiology.

In the context of plant biology, the function of stomata is a fundamental concept NEET aspirants must master. It hinges on a deep understanding of:

• Structural features of plants.
• Physiological processes like transpiration and photosynthesis.
• Environmental impact on plant functioning.

Questions related to stomata, including their role in transpiration and gas exchange, often feature in the NEET Biology section. Aspiring medical students must grasp these concepts thoroughly, as they form the basis for more advanced topics in plant physiology that could be crucial for a sound understanding of biological systems in their medical studies.