Homeostasis in Plants – Most Important MCQs with Answers

Homeostasis in plants refers to the ability of plants to maintain stable internal conditions such as water balance, gas exchange, and temperature regulation despite changes in the environment. This concept is highly important for exam preparation (MDCAT, PPSC, NEET, USMLE, etc.). Below are the 25 most repeated and important MCQs with answers.

✅ Multiple Choice Questions on Homeostasis in Plants

1. Which process helps plants maintain water balance?
A) Photosynthesis
B) Transpiration
C) Respiration
D) Osmosis
Answer: D) Osmosis

2. The opening and closing of stomata is controlled by:
A) Root hairs
B) Guard cells
C) Xylem
D) Phloem
Answer: B) Guard cells

3. Which plant hormone induces stomatal closure during drought stress?
A) Auxin
B) Gibberellin
C) Cytokinin
D) Abscisic Acid (ABA)
Answer: D) Abscisic Acid (ABA)

4. In xerophytes, water loss is reduced mainly by:
A) Large intercellular spaces
B) Sunken stomata & thick cuticle
C) Thin leaves
D) Large air cavities
Answer: B) Sunken stomata & thick cuticle

5. Hydrophytes maintain buoyancy using:
A) Thick xylem
B) Aerenchyma (air spaces)
C) Stomata on upper surface
D) Thin epidermis
Answer: B) Aerenchyma (air spaces)

6. The immediate response of a plant to drought stress is:
A) Leaf abscission
B) Root elongation
C) Stomatal closure
D) Stem elongation
Answer: C) Stomatal closure

7. Which process maintains leaf temperature in plants?
A) Respiration
B) Transpiration
C) Photosynthesis
D) Osmosis
Answer: B) Transpiration

8. The permanent wilting point in plants occurs when:
A) Soil is waterlogged
B) Roots cannot absorb water
C) Photosynthesis stops
D) CO₂ level is high
Answer: B) Roots cannot absorb water

9. Which gas regulates stomatal opening and closing?
A) Oxygen
B) Nitrogen
C) Carbon dioxide
D) Hydrogen
Answer: C) Carbon dioxide

10. In CAM plants, stomata open:
A) During the day
B) At night
C) All the time
D) During rainfall only
Answer: B) At night

11. Which adaptation helps halophytes maintain homeostasis?
A) Storing water in phloem
B) Excreting excess salt through leaves
C) Permanent stomatal closure
D) Sunken cuticle
Answer: B) Excreting excess salt through leaves

12. Loss of turgor pressure in guard cells leads to:
A) Opening of stomata
B) Closing of stomata
C) Root elongation
D) Increase in transpiration
Answer: B) Closing of stomata

13. Which structure in leaves prevents excessive water loss?
A) Epidermis
B) Cuticle
C) Phloem
D) Xylem
Answer: B) Cuticle

14. The removal of leaves during drought is called:
A) Abscission
B) Senescence
C) Transpiration
D) Wilting
Answer: A) Abscission

15. In most plants, stomata are present mainly on:
A) Upper epidermis
B) Lower epidermis
C) Midrib
D) Root surface
Answer: B) Lower epidermis

16. Entry of water into root hairs occurs by:
A) Active transport
B) Osmosis
C) Facilitated diffusion
D) Capillarity
Answer: B) Osmosis

17. Stomata usually open in:
A) Dark
B) High CO₂ concentration
C) Light when guard cells are turgid
D) Night time
Answer: C) Light when guard cells are turgid

18. A plant like cactus is an example of:
A) Halophyte
B) Xerophyte
C) Mesophyte
D) Hydrophyte
Answer: B) Xerophyte

19. Excessive transpiration may lead to:
A) Photosynthesis increase
B) Wilting
C) More stomatal opening
D) Root death
Answer: B) Wilting

20. The hormone that promotes leaf senescence is:
A) Auxin
B) Cytokinin
C) Ethylene
D) Gibberellin
Answer: C) Ethylene

21. The main role of stomata is:
A) Absorption of water
B) Control of transpiration & gas exchange
C) Food transport
D) Mineral uptake
Answer: B) Control of transpiration & gas exchange

22. Which adaptation is found in hydrophytes?
A) Sunken stomata
B) Large air chambers
C) Thick cuticle
D) Needle-like leaves
Answer: B) Large air chambers

23. The process of water loss in the form of vapor is called:
A) Evaporation
B) Guttation
C) Transpiration
D) Absorption
Answer: C) Transpiration

24. In drought conditions, plants conserve water by:
A) Expanding leaf surface
B) Closing stomata
C) Producing thin cuticle
D) Increasing transpiration
Answer: B) Closing stomata

25. Which of the following is NOT a plant homeostatic adaptation?
A) Salt glands in halophytes
B) Aerenchyma in hydrophytes
C) Stomatal closure
D) Sweating mechanism
Answer: D) Sweating mechanism

🌿 Conclusion

Homeostasis in plants ensures survival under different environmental conditions such as drought, salinity, and flooding. By understanding these MCQs, students can prepare effectively for exams and build strong concepts in plant physiology.

Comments

Post a Comment

Popular posts from this blog

Image
  Smart Bio Notes"Hand-Drawn Chloroplast Diagram + Easy Explanation – Watch Now! 🎥" 🔬  What is a Chloroplast? "Chlorophyll is the green color in plants that acts like a solar panel, capturing sunlight to help the plant make its own food through photosynthesis." INTRODUCTION Chlorophyll is a green pigment found in plants, algae, and some bacteria. It is located in the chloroplasts of plant cells. Chlorophyll is essential for photosynthesis , the process by which plants make food. It absorbs sunlight , mainly blue and red light, and reflects green light (which is why plants look green). There are different types of chlorophyll , like chlorophyll a and b , with chlorophyll a being the most common. In this blog, we’ll explore the structure, function, and importance of chloroplasts with a detailed hand-drawn diagram to make learning easy for your exams and fun! 🎨📚 📌 Where Are Chloroplasts Found? Chloroplast has chlorophyll that is green in color thats why...
Read more
Image
"Cell Membrane: The Ultimate Protective Shield of Life – Structure, Functions & Importance" 🚀🔬 The cell membrane , also known as the plasma membrane , is an essential component of all living cells. It serves as a protective barrier , controlling what enters and exits the cell while maintaining a stable internal environment. Without it, cells would not be able to function properly! Structure of the Cell Membrane The cell membrane follows the fluid mosaic model , meaning it is flexible and consists of multiple components working together. Its structure includes: Phospholipid Bilayer : Two layers of molecules that form the boundary of the cell. The top circles are hydrophilic heads (water loving), and the tails inside are hydrophobic (water fearing). this keeps the cell safe! Proteins : Various proteins are embedded in the membrane, acting as channels.These are like tiny doors that control what enters and leaves the cell. Cholesterol : This molecule helps prevent cell mem...
Read more
Image
"Centrioles: Small Organelles, Big Impact on Your Cells" Cells have tiny structures that control how they divide?  Centrioles are small cylindrical structures found in animal cells, playing a key role in organizing the microtubules and facilitating cell division. Though often overlooked, these tiny organelles are critical in maintaining the shape and function of cells. What Are Centrioles? Centrioles are composed of 9 microtubules triplet arranged in a 9+0 pattern  in a cylindrical shape, each triplet consists of  three microtubules . Location Centrioles are found in the centrosome, a granular mass that serves as a microtubule organizing center(MTOC) Animal cells only Centrioles are only foundin animal cells. Centrioles in Cell Organization 1. Structure of Centrioles Cylindrical Shape : Centrioles are small, cylindrical structures found in the cytoplasm of animal cells. They are composed of microtubules arranged in a specific pattern: 9 sets of three microtubules ...
Read more