Free Forms and Functions of Plants MCQs with Answers

211. A living tissue which in addition to its regular fianction also provides support to plants is:

• A. Xylem
• B. Collenchyma
• C. Sclerenchyma
• D. Parenchyma

Explanation: Collenchyma is living tissue that provides support to the plant as it has extra cellulose deposited in its cell wall the cell wall is non-lignified.

212. Photorespiration accurs when:

• A. Stomata are opened
• B. Day is humid
• C. Concentration of CO2 inside the leaf is high
• D. Concentration of O2 inside leaf is high

Explanation: Photorespiration occurs when Rubisco, an enzyme involved in photosynthesis, binds with O2 instead of CO2. This process is more likely when the concentration of O2 inside the leaf is high, which happens when stomata are closed to prevent water loss in hot and dry climates. Consequently, CO2 levels drop, and O2 levels rise, increasing the likelihood of photorespiration. Thus, option D is correct. The other options are incorrect because open stomata (option A) and high CO2 levels (option C) favor photosynthesis, and humid conditions (option B) typically result in open stomata, reducing the chance of photorespiration.

213. Which one of the following plants feeds on water mites?

• A. Nepenthes
• B. Utricularia
• C. Dionea
• D. Sundew

Explanation: Drosera or sundew is a carnivorous plant found in moist, acidic, and nutrient-deficient soils. Such places are home to mosquitos and other insects and drosera feed on these to fulfill their nitrogen needs.

214. The opening and closing of stomata are controlled by which of the following factor(s)?

• A. Sugar
• B. pH
• C. Potassium
• D. All of the above

Explanation: The opening and closing of stomata are primarily controlled by the conversion of starch to sugar and vice versa in guard cells. During the daytime, sugar increases osmotic pressure, leading to stomata opening, while at night, starch reduces osmotic pressure, causing stomata closure. While pH and potassium are important factors in plant physiology, they are not the main drivers of stomata regulation through the starch-sugar interconversion mechanism.

215. Mangroves are:

• A. Xerophytes
• B. Mesophytes
• C. Halophytes
• D. Hydrophytes

Explanation: Mangroves are tropical plants that are adapted to lose, wet soils, salt water and being periodically submerged by tides

216. Calvin cycle takes place within:

• A. Stoma of chloroplasts
• B. Granum of the chloroplast
• C. Cytoplasm of the cell
• D. ....

Explanation: Unlike the light reactions, which take place in the thylakoid membrane, the reactions of the Calvin cycle take place in the stroma, the inner space of chloroplasts.

217. Which of the following meristem is responsible for wood formation in plants :

• A. Lateral meristem
• B. Apical meristem
• C. Intercalary
• D. None

Explanation: The meristem responsible for wood formation in plants is the lateral meristem, specifically the vascular cambium and the cork cambium. Lateral meristems are responsible for the secondary growth of plants, which involves the thickening of stems and roots. The vascular cambium is a type of lateral meristem located between the xylem and phloem tissues in the stems and roots of woody plants. It produces new xylem cells towards the center of the stem, contributing to the growth of wood. The cork cambium, another lateral meristem, produces the outer bark of the stem, providing protection to the underlying tissues.

218. Which of the following physiological phenomenon is responsible of guttation :

• A. Capillary rise of water
• B. Root pressure
• C. Tensile strength
• D. All of these

Explanation: Guttation is the process by which plants excrete excess water in the form of droplets through specialized structures called hydathodes. It typically occurs during the night or early morning when the soil moisture is high and the transpiration rate is low.

219. Crop rotation leads to:

• A. Increase in the soil nutrient
• B. More aeration of soil
• C. Soil fertility
• D. ....

Explanation: Crop rotation helps return nutrients to the soil without synthetic inputs. The practice also works to interrupt pest and disease cycles, improve soil health by increasing biomass from different crops' root structures, and increase biodiversity on the farm.

220. In a woody-plant the·number of structures on ion sin cell has to cross to reach the adjunction cell is:

• A. 3
• B. 5
• C. 6
• D. 7

Explanation: The ion crosses three main structures when moving from one cell to an adjacent cell in a woody plant:Middle Lamella: This is the pectin-rich layer which cements the cell walls of two adjoining plant cells together.Primary Cell Wall: This is the outermost layer of the cell wall, which is flexible and allows for cell growth.Secondary Cell Wall: This is a thicker and more rigid structure found beneath the primary cell wall, common in woody plants to provide strength and support.These structures are essential for providing support and protection, while also facilitating the movement of ions via channel proteins, as the cell membrane itself is non-polar and ions are polar. Options B, C, and D include additional or irrelevant structures that are not necessary for ion movement between adjacent cells.