Transport In Plants

The correct option is (B) : Tracheids are multicellular and with narrow lumen

The set of natural numbers is 1, 2, 3,. The set of whole numbers is 0,1,2,3,..... Every natural number is undoubtedly a whole number.

The correct option is (B): Alkaline

Explanation:

Phloem sap is spread throughout the plant; it delivers nutrients (mainly sugars) produced during photosynthesis to various parts of the plant. When phloem sap is collected and tested, it will have an alkaline pH due to the presence of amino acids and organic acids, which can contribute to a slightly basic solution.

Here are the other options and why they are incorrect:

A) Low refractive index: Phloem sap may contain sugars as well as other substances. The presence of other solutes can affect the refractive index, making it difficult to identify.

C) Absence of sugar: Sugar is a key component of phloem sap as it transports the products of photosynthesis throughout the plant.

D) Acidic: Phloem sap typically has a slightly alkaline pH due to the presence of amino acids and organic acids.

Thus, the right answer to this question is alkaline.

• Movement of water occurs through intercellular spaces and wall of the cells: This is correct, as the apoplastic pathway operates through the spaces between cells and within cell walls.
• The movement does not involve crossing of cell membrane: This statement is true for the apoplastic pathway, which specifically avoids crossing cell membranes.
• The movement is aided by cytoplasmic streaming: This is incorrect for the apoplastic pathway. Cytoplasmic streaming occurs in the symplastic pathway, where substances move from cell to cell through plasmodesmata.
• Apoplast is continuous and does not provide any barrier to water movement: This is generally true until it reaches areas like the Casparian strip in roots, which blocks the apoplast.

The concept of water potential is crucial in understanding how water moves through plant tissues. Water potential ( ) is a measure of the potential energy in water, particularly important in osmosis, which determines the direction and rate of water movement.

Water potential is influenced by the presence of solutes and pressure. It is defined mathematically as:

Where:

• = Total water potential
• = Solute potential (also known as osmotic potential)
• = Pressure potential

Adding more solutes to a solution affects the solute potential ( ). Solute potential is always negative because solutes lower the potential of water. The addition of solutes makes the solute potential more negative, thus lowering the overall water potential ( ). This can be expressed as:

Therefore, the correct answer is:

• Lower its water potential.

The task is to match the terms related to biological concepts in List-I with their corresponding descriptions in List-II. Let's break down each pair:

Explanation:

• Cohesion: Refers to the mutual attraction among molecules of the same substance, such as water molecules attracting each other, making it correct to match (a) with (ii).
• Adhesion: Describes the attraction between molecules of different substances, such as water molecules and polar surfaces, matching (b) with (iv).
• Surface Tension: Arises from the cohesive forces among liquid molecules, leading to more attraction within the liquid phase, making (c) match with (i).
• Guttation: Involves the exudation of water droplets from plant leaves in liquid form, identifying (d) as matching with (iii).

Thus, the correct matches are: A – II, B – IV, C – I, D – III.

Statement I is correct: Transpiration creates a negative pressure or tension in the xylem, which generates forces that can lift a column of water up to considerable heights. This phenomenon is known as the cohesion-tension theory and is an important mechanism for water transport in plants.

Statement II is correct: Transpiration does indeed cool leaf surfaces through evaporative cooling. As water is lost through stomata during transpiration, it takes heat energy with it, thus cooling the leaf surface. This cooling effect can range from 10 to 15 degrees Celsius or even more, depending on environmental conditions.

Therefore, The correct option is (D): Both Statement I and Statement II are correct

The correct match between List I and List II is:

A. Heroine - Slow down body function
Heroin, an opioid derived from morphine, is a potent narcotic. It slows down the body’s function by acting on the central nervous system, leading to drowsiness, decreased respiration, and a feeling of euphoria. This matches with the correct description in List II as it inhibits the normal functioning of the brain and the body.

B. Marijuana - Effect on cardiovascular system
Marijuana, also known as cannabis, affects the cardiovascular system by increasing heart rate and blood pressure immediately after consumption. Its active ingredient, THC, interacts with the brain’s cannabinoid receptors and can have both short-term and long-term cardiovascular effects, including an increased risk of heart attack in some individuals.

C. Cocaine - Interfere with transport of dopamine
Cocaine is a stimulant drug that interferes with the reuptake of dopamine, a neurotransmitter involved in mood regulation and pleasure. By blocking dopamine transporters, cocaine causes an accumulation of dopamine in the brain, leading to intense feelings of euphoria. This interference is the primary reason why cocaine is addictive.

D. Morphine - Painkiller, obtained from latex of poppy plant
Morphine is an opioid and a powerful painkiller that is derived from the latex of the opium poppy plant. It is commonly used in medical settings to manage severe pain, particularly after surgery or injury, due to its potent analgesic properties.

The correct option is (D): A-II, B-I, C-IV, D-III

Conclusion: Understanding the effects of these substances is critical, as they have significant physiological impacts. Heroin (A) slows down body function, marijuana (B) affects the cardiovascular system, cocaine (C) interferes with the dopamine transport, and morphine (D) is a potent painkiller obtained from the poppy plant. This question tests knowledge of drug classifications and their associated health risks.