Stomata Types and Functions Practice Questions
19 free Stomata Types and Functions practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Stomata are primarily found in which part of the plant?
- A Root tissue
- B Stem epidermis
- C Leaf epidermis
- D Xylem tissue
Correct answer: Leaf epidermis
Stomata are small openings present mainly on the leaf epidermis. They facilitate gas exchange and transpiration.
Which cells surround the stomatal pore?
- A Cortex cells
- B Guard cells
- C Xylem cells
- D Phloem cells
Correct answer: Guard cells
Guard cells surround the stomatal pore and regulate its opening and closing. They are specialized epidermal cells.
What is the main function of stomata?
- A Photosynthesis
- B Water absorption
- C Exchange of gases
- D Transport of food
Correct answer: Exchange of gases
Stomata allow exchange of gases like CO2 and O2. They also help in transpiration.
Which gas enters the leaf through stomata during photosynthesis?
- A Oxygen
- B Nitrogen
- C Carbon monoxide
- D Carbon dioxide
Correct answer: Carbon dioxide
Carbon dioxide enters through stomata and is used in photosynthesis. Oxygen is released as a by-product.
Which shape of guard cells is found in dicots?
- A Dumbbell-shaped
- B Rectangular
- C Oval
- D Kidney-shaped
Correct answer: Kidney-shaped
In dicots, guard cells are kidney-shaped. This structure helps regulate stomatal opening.
Which shape of guard cells is found in monocots?
- A Kidney-shaped
- B Dumbbell-shaped
- C Triangular-shaped
- D Circular-shaped
Correct answer: Dumbbell-shaped
In monocots, guard cells are dumbbell-shaped. This is typical of grasses.
What causes stomatal opening?
- A Loss of turgor pressure in guard cells
- B Increase in turgor in guard cells
- C Decrease in water content
- D Cell death
Correct answer: Increase in turgor in guard cells
Stomata open when guard cells become turgid. This occurs due to water uptake.
What leads to stomatal closure?
- A Increase in turgor pressure
- B Decrease in turgor pressure
- C Increase in photosynthesis
- D Increase in CO2 intake
Correct answer: Decrease in turgor pressure
Stomata close when guard cells lose turgor. This happens when water exits the cells.
Which process is mainly controlled by stomata?
- A Plant respiration
- B Transpiration
- C Digestion
- D Root absorption
Correct answer: Transpiration
Stomata regulate transpiration by controlling water vapor loss. This helps maintain water balance.
Which type of stomata is surrounded by subsidiary cells arranged parallel to guard cells?
- A Paracytic
- B Anomocytic
- C Diacytic
- D Actinocytic
Correct answer: Paracytic
Paracytic stomata have subsidiary cells parallel to the guard cells. This arrangement is seen in many plants.
Which type of stomata lacks distinct subsidiary cells?
- A Anomocytic
- B Paracytic
- C Diacytic
- D Actinocytic
Correct answer: Anomocytic
Anomocytic stomata do not have specialized subsidiary cells. They are surrounded by ordinary epidermal cells.
Which stomatal type has two subsidiary cells at right angles to guard cells?
- A Anomocytic
- B Paracytic
- C Actinocytic stomata
- D Diacytic stomata
Correct answer: Diacytic stomata
Diacytic stomata have two subsidiary cells perpendicular to the guard cells. This is seen in certain dicots.
Which stomatal type has multiple subsidiary cells arranged in a circle?
- A Anomocytic stomata
- B Paracytic
- C Diacytic
- D Actinocytic
Correct answer: Actinocytic
Actinocytic stomata have several subsidiary cells arranged radially around the guard cells.
What is transpiration?
- A Water vapor loss from plants
- B Absorption of water by roots
- C Photosynthesis in leaves
- D Respiration in cells
Correct answer: Water vapor loss from plants
Transpiration is the loss of water vapor from aerial parts of plants. It mainly occurs through stomata.
Which factor promotes stomatal opening?
- A Darkness
- B High CO2 concentration
- C Water deficiency
- D Sunlight
Correct answer: Sunlight
Light stimulates stomatal opening. Guard cells become turgid due to active transport of ions.
Which factor leads to stomatal closure?
- A High humidity
- B Adequate water supply
- C Low CO2 concentration
- D Severe water stress
Correct answer: Severe water stress
Water stress causes guard cells to lose turgor. This leads to stomatal closure to prevent water loss.
Which ion accumulation is associated with stomatal opening?
- A Potassium ions
- B Calcium ions
- C Sodium ions
- D Excess chloride ions
Correct answer: Potassium ions
Potassium ions accumulate in guard cells, increasing osmotic pressure. This leads to water influx and stomatal opening.
Which type of stomata is common in dicot leaves?
- A Anomocytic
- B Paracytic
- C Diacytic
- D Actinocytic
Correct answer: Anomocytic
Anomocytic stomata are common in dicots. They lack distinct subsidiary cells.
Stomata are more numerous on which surface of a dicot leaf?
- A Lower surface
- B Upper surface
- C Both surfaces equally
- D Stem surface
Correct answer: Lower surface
In dicot leaves, stomata are more abundant on the lower surface. This reduces water loss.