Here below some basic MCQ’s about “Transport in Plants” with answer which is explained in details. Lets check one by one which is given in below.
Question 1:
Which of the following is primarily responsible for the transport of water and minerals in plants?
A) Phloem
B) Xylem
C) Cortex
D) Pith
Answer: B) Xylem
Explanation: Xylem is the tissue responsible for the conduction of water and dissolved minerals from the roots to other parts of the plant. It consists of vessels and tracheids that facilitate this transport. Phloem, on the other hand, primarily transports organic nutrients (especially sugars) produced through photosynthesis.
Question 2:
What is the main mechanism by which water moves from the roots to the leaves in plants?
A) Active transport
B) Diffusion
C) Cohesion and adhesion
D) Osmosis
Answer: C) Cohesion and adhesion
Explanation: Water movement in plants occurs primarily through cohesion (water molecules sticking to each other) and adhesion (water molecules sticking to the walls of the xylem vessels). This combination creates a continuous column of water that can be pulled upward through transpiration.
Question 3:
Which part of the plant is responsible for the majority of photosynthesis and consequently the production of food transported by phloem?
A) Roots
B) Stems
C) Leaves
D) Flowers
Answer: C) Leaves
Explanation: Leaves contain chloroplasts where photosynthesis occurs, producing sugars that are then transported through the phloem to other parts of the plant. The broad surface area of leaves maximizes light absorption for this process.
Question 4:
What is the term for the movement of water vapor from the inside of a leaf to the atmosphere?
A) Transpiration
B) Respiration
C) Evaporation
D) Photosynthesis
Answer: A) Transpiration
Explanation: Transpiration is the process by which water vapor exits the leaf through stomata. This loss of water creates a negative pressure that helps pull more water up from the roots through the xylem.
Question 5:
Which structure regulates the opening and closing of stomata?
A) Parenchyma
B) Sclerenchyma
C) Guard cells
D) Mesophyll
Answer: C) Guard cells
Explanation: Guard cells surround each stoma (the pore on the leaf surface) and control its opening and closing. This regulation is crucial for balancing water loss through transpiration with gas exchange for photosynthesis.
Question 6:
What drives the movement of water through the xylem?
A) Root pressure
B) Capillary action
C) Transpiration pull
D) Active transport
Answer: C) Transpiration pull
Explanation: Transpiration pull is the primary force driving water movement through the xylem. As water evaporates from the leaves, it creates negative pressure that pulls more water up from the roots.
Question 7:
Which of the following statements about phloem is true?
A) Phloem transports water only.
B) Phloem is made up of vessel elements.
C) Phloem transports organic nutrients.
D) Phloem does not have living cells.
Answer: C) Phloem transports organic nutrients.
Explanation: Phloem is responsible for the transport of organic compounds, particularly sugars produced during photosynthesis. It contains living cells, such as sieve elements and companion cells.
Question 8:
The phenomenon of “guttation” occurs due to:
A) High transpiration rates
B) Root pressure
C) Low humidity
D) Stomatal closure
Answer: B) Root pressure
Explanation: Guttation is the process where water droplets are expelled from the edges of leaves, primarily due to root pressure. This usually occurs at night when transpiration is low.
Question 9:
In which part of the plant does most absorption of water and minerals occur?
A) Stems
B) Leaves
C) Roots
D) Flowers
Answer: C) Roots
Explanation: Roots are the primary organs for the absorption of water and minerals from the soil. Root hairs increase the surface area for absorption.
Question 10:
What is the role of the Casparian strip in plant roots?
A) Water storage
B) Nutrient absorption
C) Regulation of water and solute movement
D) Photosynthesis
Answer: C) Regulation of water and solute movement
Explanation: The Casparian strip is a waxy barrier in the endodermis of roots that regulates the movement of water and dissolved substances into the vascular system, ensuring that materials must pass through cell membranes.
Question 11:
Which process describes the movement of ions against their concentration gradient in plant cells?
A) Passive transport
B) Active transport
C) Diffusion
D) Osmosis
Answer: B) Active transport
Explanation: Active transport is the process by which ions are moved against their concentration gradient, requiring energy, usually in the form of ATP. This is crucial for nutrient uptake in plants.
Question 12:
Which of the following is NOT a function of water in plants?
A) Photosynthesis
B) Structural support
C) Nutrient transport
D) Energy storage
Answer: D) Energy storage
Explanation: Water is essential for photosynthesis, structural support, and nutrient transport, but it does not function as an energy storage molecule. Energy in plants is stored in the form of carbohydrates.
Question 13:
The primary method of sugar transport in plants is through:
A) Xylem
B) Phloem
C) Parenchyma
D) Sclerenchyma
Answer: B) Phloem
Explanation: Phloem is responsible for transporting sugars and other organic nutrients from the leaves (where they are produced) to other parts of the plant.
Question 14:
Which of the following environmental factors can increase the rate of transpiration?
A) High humidity
B) Low temperature
C) High wind speed
D) Abundant soil moisture
Answer: C) High wind speed
Explanation: High wind speed increases transpiration rates by moving moisture-saturated air away from the leaf surface, allowing more water to evaporate.
Question 15:
The primary tissue responsible for photosynthesis in leaves is:
A) Epidermis
B) Xylem
C) Phloem
D) Mesophyll
Answer: D) Mesophyll
Explanation: Mesophyll tissue in leaves contains chloroplasts where photosynthesis takes place, converting light energy into chemical energy.
Question 16:
Which of the following conditions would most likely lead to stomatal closure?
A) High light intensity
B) Low atmospheric humidity
C) High temperature
D) Abundant water supply
Answer: B) Low atmospheric humidity
Explanation: Low humidity can lead to increased water loss from the leaf, prompting stomata to close to conserve water.
Question 17:
Root pressure is most prominent in:
A) Trees
B) Herbaceous plants
C) Shrubs
D) Aquatic plants
Answer: B) Herbaceous plants
Explanation: Root pressure is more prominent in herbaceous (non-woody) plants, where it can help push water upward through the plant, especially at night.
Question 18:
In plants, the movement of water and nutrients is primarily facilitated by:
A) Diffusion alone
B) Active transport alone
C) Both diffusion and active transport
D) Only through xylem
Answer: C) Both diffusion and active transport
Explanation: Water and nutrient movement involves both passive processes like diffusion and active processes that require energy, such as active transport.
Question 19:
The pressure flow hypothesis explains the movement of:
A) Water in xylem
B) Nutrients in phloem
C) Gases in stomata
D) Minerals in soil
Answer: B) Nutrients in phloem
Explanation: The pressure flow hypothesis describes how sugars are actively transported into the phloem, creating a pressure gradient that facilitates the flow of nutrients throughout the plant.
Question 20:
Which type of transport is mainly involved in the uptake of water by root hairs?
A) Active transport
B) Facilitated diffusion
C) Osmosis
D) Bulk flow
Answer: C) Osmosis
Explanation: Osmosis is the passive movement of water across a semi-permeable membrane from an area of low solute concentration to high solute concentration, which is how water is primarily absorbed by root hairs.
Question 21:
What is the main purpose of the stomata in leaves?
A) Gas exchange
B) Water storage
C) Nutrient absorption
D) Photosynthesis
Answer: A) Gas exchange
Explanation: Stomata are tiny openings on the leaf surface that allow for the exchange of gases (CO₂ and O₂) necessary for photosynthesis and respiration.
Question 22:
Which part of the plant is primarily responsible for the absorption of sunlight?
A) Roots
B) Stems
C) Leaves
D) Flowers
Answer: C) Leaves
Explanation: Leaves contain chlorophyll, the pigment that captures sunlight for photosynthesis, making them the primary site for light absorption in plants.
Question 23:
The term “hydrophilic” refers to substances that:
A) Repel water
B) Absorb water
C) Are water-resistant
D) Contain lipids
Answer: B) Absorb water
Explanation: Hydrophilic substances have an affinity for water, meaning they can absorb or interact with water molecules.
Question 24:
Which of the following is a method by which plants can regulate their internal water levels?
A) Stomatal opening and closing
B) Guttation
C) Root pressure
D) All of the above
Answer: D) All of the above
Explanation: Plants regulate water levels through various mechanisms, including the opening and closing of stomata, guttation, and root pressure.
Question 25:
What is the role of companion cells in phloem?
A) Transport water
B) Aid in the transport of sugars
C) Provide structural support
D) Store nutrients
Answer: B) Aid in the transport of sugars
Explanation: Companion cells are associated with sieve elements in phloem and help in the loading and unloading of sugars and nutrients.
Question 26:
The main driving force for the movement of nutrients in phloem is:
A) Root pressure
B) Capillary action
C) Pressure gradient
D) Gravity
Answer: C) Pressure gradient
Explanation: The movement of nutrients in phloem occurs due to the pressure gradient created by the active transport of sugars into the phloem, which leads to the flow of sap from areas of high pressure to low pressure.
Question 27:
What type of cells in xylem are primarily responsible for water transport?
A) Sieve tubes
B) Tracheids
C) Companion cells
D) Parenchyma
Answer: B) Tracheids
Explanation: Tracheids are elongated cells in xylem that facilitate the conduction of water and minerals through their perforated walls.
Question 28:
Which process describes the movement of water through the xylem by cohesion?
A) Transpiration
B) Capillary action
C) Root pressure
D) Osmosis
Answer: B) Capillary action
Explanation: Capillary action occurs due to cohesion (water molecules sticking to each other) and adhesion (water molecules sticking to the xylem walls), allowing water to rise in narrow tubes.
Question 29:
Which part of the plant primarily experiences the highest rate of transpiration?
A) Roots
B) Flowers
C) Stems
D) Leaves
Answer: D) Leaves
Explanation: Leaves have a large surface area and numerous stomata, making them the primary site for transpiration, where water vapor exits into the atmosphere.
Question 30:
In which of the following conditions is transpiration most likely to be highest?
A) Cool and humid
B) Hot and dry
C) Overcast
D) Cold and wet
Answer: B) Hot and dry
Explanation: High temperatures and low humidity increase the rate of water evaporation from the leaf surface, resulting in higher transpiration rates.
Question 31:
Which of the following is NOT a function of the xylem?
A) Transport of water
B) Transport of nutrients
C) Structural support
D) Storage of carbohydrates
Answer: D) Storage of carbohydrates
Explanation: Xylem primarily transports water and minerals and provides structural support but does not store carbohydrates; this is the function of phloem and parenchyma cells.
Question 32:
What is the function of the pericycle in plant roots?
A) Nutrient absorption
B) Water storage
C) Formation of lateral roots
D) Photosynthesis
Answer: C) Formation of lateral roots
Explanation: The pericycle is a layer of cells in the root that can give rise to lateral roots, helping the plant to explore a larger volume of soil for water and nutrients.
Question 33:
The primary component of the plant cell wall that provides strength is:
A) Cellulose
B) Lignin
C) Hemicellulose
D) Pectin
Answer: A) Cellulose
Explanation: Cellulose is a polysaccharide that forms the primary structural component of the plant cell wall, providing rigidity and strength.
Question 34:
Which process allows plants to take in minerals from the soil?
A) Diffusion
B) Filtration
C) Osmosis
D) Active transport
Answer: D) Active transport
Explanation: Active transport is required for the uptake of minerals against their concentration gradient, allowing plants to absorb essential nutrients from the soil.
Question 35:
Which plant hormone is primarily involved in regulating stomatal closure during water stress?
A) Auxin
B) Cytokinins
C) Abscisic acid (ABA)
D) Ethylene
Answer: C) Abscisic acid (ABA)
Explanation: Abscisic acid (ABA) signals stomatal closure during water stress, helping to conserve water in the plant.
Question 36:
In plants, the term “hydraulic conductivity” refers to:
A) The ability of water to move through soil
B) The rate at which water moves through plant tissues
C) The capacity of roots to absorb water
D) The resistance of xylem to water flow
Answer: B) The rate at which water moves through plant tissues
Explanation: Hydraulic conductivity measures how easily water can move through plant tissues, particularly in xylem.
Question 37:
What is the primary source of energy for the active transport of nutrients in plants?
A) Sunlight
B) ATP
C) Glucose
D) Photosynthesis
Answer: B) ATP
Explanation: Active transport in plants requires energy, which is provided by ATP (adenosine triphosphate) produced during cellular respiration.
Question 38:
The term “sink” in the context of phloem transport refers to:
A) A source of water
B) An area of nutrient production
C) A site where nutrients are consumed or stored
D) An area of photosynthesis
Answer: C) A site where nutrients are consumed or stored
Explanation: In phloem transport, a “sink” is any part of the plant that consumes or stores sugars, such as roots, fruits, and developing leaves.
Question 39:
Which of the following adaptations helps reduce water loss in plants?
A) Large leaves
B) Thick cuticle
C) Open stomata
D) Shallow roots
Answer: B) Thick cuticle
Explanation: A thick cuticle on leaf surfaces minimizes water loss by reducing evaporation, helping the plant retain moisture.
Question 40:
The main tissue responsible for the transport of food in plants is:
A) Xylem
B) Sclerenchyma
C) Phloem
D) Parenchyma
Answer: C) Phloem
Explanation: Phloem is the vascular tissue responsible for the transport of organic nutrients, particularly sugars, throughout the plant.
Question 41:
The process by which water moves from the soil into plant roots is called:
A) Transpiration
B) Absorption
C) Evaporation
D) Filtration
Answer: B) Absorption
Explanation: Absorption refers to the process by which water and minerals move from the soil into plant roots through root hairs and other structures.
Question 42:
What is the primary driving force behind the movement of water in the xylem during the day?
A) Root pressure
B) Capillary action
C) Transpiration pull
D) Osmosis
Answer: C) Transpiration pull
Explanation: During the day, transpiration pull creates a negative pressure that helps draw water up from the roots through the xylem.
Question 43:
Which type of transport is mainly responsible for the movement of sucrose in phloem?
A) Passive transport
B) Facilitated diffusion
C) Active transport
D) Simple diffusion
Answer: C) Active transport
Explanation: The movement of sucrose into phloem is often an active process, requiring energy to transport sugars against their concentration gradient.
Question 44:
The root cap is primarily involved in:
A) Nutrient absorption
B) Protecting the root meristem
C) Water transport
D) Photosynthesis
Answer: B) Protecting the root meristem
Explanation: The root cap protects the delicate meristematic tissue at the root tip as it pushes through the soil.
Question 45:
Which of the following factors does NOT affect the rate of transpiration?
A) Temperature
B) Humidity
C) Soil pH
D) Wind speed
Answer: C) Soil pH
Explanation: While temperature, humidity, and wind speed significantly affect the rate of transpiration, soil pH has a more indirect effect on overall plant health rather than directly influencing transpiration rates.
Question 46:
What is the function of aerenchyma in aquatic plants?
A) Nutrient storage
B) Gas exchange and buoyancy
C) Water retention
D) Photosynthesis
Answer: B) Gas exchange and buoyancy
Explanation: Aerenchyma consists of loosely packed cells with large air spaces that facilitate gas exchange and help keep aquatic plants buoyant.
Question 47:
Which part of the plant is responsible for the majority of nutrient storage?
A) Leaves
B) Roots
C) Stems
D) Flowers
Answer: B) Roots
Explanation: Roots serve as storage organs for carbohydrates and other nutrients, allowing the plant to draw on these reserves during periods of growth or stress.
Question 48:
The majority of water absorbed by roots comes from which part of the soil?
A) Topsoil
B) Subsoil
C) Bedrock
D) All soil layers equally
Answer: A) Topsoil
Explanation: The topsoil layer typically contains the highest concentration of nutrients and moisture, making it the primary source of water for roots.
Question 49:
The transport of nutrients in the phloem is mainly through:
A) Vascular bundles
B) Sieve tubes
C) Tracheids
D) Xylem vessels
Answer: B) Sieve tubes
Explanation: Sieve tubes are specialized structures in phloem that facilitate the transport of nutrients and sugars throughout the plant.
Question 50:
Which of the following structures helps in increasing the surface area for absorption in roots?
A) Stomata
B) Root hairs
C) Xylem vessels
D) Guard cells
Answer: B) Root hairs
Explanation: Root hairs are extensions of root epidermal cells that increase the surface area for water and nutrient absorption from the soil.
Question 51:
Which of the following plant hormones promotes the opening of stomata?
A) Auxin
B) Ethylene
C) Cytokinins
D) Gibberellins
Answer: A) Auxin
Explanation: Auxins can influence stomatal opening by affecting the growth and turgor of guard cells, although abscisic acid primarily promotes stomatal closure.
Question 52:
The primary function of the cuticle in plant leaves is to:
A) Facilitate gas exchange
B) Protect against herbivores
C) Reduce water loss
D) Store nutrients
Answer: C) Reduce water loss
Explanation: The cuticle is a waxy layer that covers the leaf surface, minimizing water loss by reducing evaporation.
Question 53:
What role do plasmodesmata play in plant cells?
A) Water transport
B) Nutrient transport
C) Cell communication
D) Photosynthesis
Answer: C) Cell communication
Explanation: Plasmodesmata are small channels that connect adjacent plant cells, allowing for communication and transport of small molecules between them.
Question 54:
The cohesion-tension theory explains:
A) The movement of sugars in phloem
B) The movement of water in xylem
C) The uptake of nutrients by roots
D) The process of photosynthesis
Answer: B) The movement of water in xylem
Explanation: The cohesion-tension theory describes how water is pulled upward through the xylem due to the cohesive properties of water molecules and the tension created by transpiration.
Question 55:
In which plant tissue does photosynthesis primarily occur?
A) Sclerenchyma
B) Parenchyma
C) Collenchyma
D) Epidermis
Answer: B) Parenchyma
Explanation: Parenchyma cells contain chloroplasts and are primarily responsible for photosynthesis in plant tissues.
Question 56:
Which of the following conditions would lead to increased root pressure?
A) High humidity
B) Low temperature
C) Abundant soil moisture
D) All of the above
Answer: D) All of the above
Explanation: High humidity, low temperature, and abundant soil moisture can all contribute to increased root pressure, as these conditions promote water uptake by roots.
Question 57:
The function of the stomatal complex includes:
A) Water storage
B) Nutrient transport
C) Gas exchange
D) All of the above
Answer: C) Gas exchange
Explanation: The stomatal complex primarily facilitates gas exchange (CO₂ and O₂) during photosynthesis and respiration.
Question 58:
Which of the following factors can decrease the rate of photosynthesis in plants?
A) High light intensity
B) Low CO₂ concentration
C) Warm temperatures
D) Abundant water supply
Answer: B) Low CO₂ concentration
Explanation: Low concentrations of CO₂ limit the photosynthetic process, as it is a key reactant in photosynthesis.
Question 59:
What mechanism allows for the upward movement of water in plants against gravity?
A) Diffusion
B) Osmosis
C) Cohesion and adhesion
D) Root pressure
Answer: C) Cohesion and adhesion
Explanation: The upward movement of water in plants is facilitated by cohesion (water molecules sticking to each other) and adhesion (water molecules sticking to the walls of the xylem).
Question 60:
In plants, the term “source” refers to:
A) A site of water uptake
B) A site of sugar production
C) A site of nutrient storage
D) A site of gas exchange
Answer: B) A site of sugar production
Explanation: In phloem transport, a “source” is any part of the plant that produces sugars, such as leaves during photosynthesis.
Question 61:
The primary function of xylem vessels is to:
A) Transport sugars
B) Transport water
C) Store nutrients
D) Conduct photosynthesis
Answer: B) Transport water
Explanation: Xylem vessels are specialized for transporting water and minerals from the roots to the rest of the plant.
Question 62:
Which of the following factors can enhance the rate of photosynthesis?
A) Low light intensity
B) High temperature
C) Increased carbon dioxide concentration
D) Decreased humidity
Answer: C) Increased carbon dioxide concentration
Explanation: Higher levels of carbon dioxide can enhance photosynthesis, as it is one of the key reactants in the process.
Question 63:
What is the main role of phloem in plants?
A) Support
B) Nutrient transport
C) Water transport
D) Gas exchange
Answer: B) Nutrient transport
Explanation: Phloem is primarily responsible for transporting organic nutrients, particularly sugars, from photosynthetic tissues to other parts of the plant.
Question 64:
Which of the following is a characteristic of transpiration?
A) It is an active process.
B) It helps in nutrient uptake.
C) It occurs only at night.
D) It creates a negative pressure in the xylem.
Answer: D) It creates a negative pressure in the xylem.
Explanation: Transpiration leads to a negative pressure in the xylem, which helps pull water upward from the roots.
Question 65:
What type of tissue is primarily responsible for the transport of water in the root?
A) Parenchyma
B) Xylem
C) Phloem
D) Collenchyma
Answer: B) Xylem
Explanation: Xylem tissue is responsible for the transport of water and dissolved minerals from the roots to the rest of the plant.
Question 66:
The primary site for photosynthesis in a leaf is located in the:
A) Epidermis
B) Stomata
C) Mesophyll
D) Cuticle
Answer: C) Mesophyll
Explanation: Mesophyll cells contain chloroplasts where photosynthesis occurs, making them the primary site for this process in leaves.
Question 67:
What is the role of the sieve plate in phloem?
A) Water transport
B) Nutrient absorption
C) Facilitating the flow of sap
D) Storage of carbohydrates
Answer: C) Facilitating the flow of sap
Explanation: Sieve plates are perforated structures in phloem that allow for the efficient flow of sap and nutrients between sieve tube elements.
Question 68:
Which of the following processes does NOT occur in the xylem?
A) Water conduction
B) Mineral transport
C) Photosynthesis
D) Support
Answer: C) Photosynthesis
Explanation: Photosynthesis occurs in the chloroplasts of mesophyll cells, not in the xylem. The xylem’s primary functions are water conduction, mineral transport, and providing structural support.
Question 69:
Which type of roots is adapted to enhance water absorption in arid conditions?
A) Shallow roots
B) Deep roots
C) Adventitious roots
D) Aerial roots
Answer: B) Deep roots
Explanation: Deep roots can access moisture from deeper soil layers, making them advantageous for water absorption in arid conditions.
Question 70:
The movement of water through a plant is mainly influenced by:
A) Soil pH
B) Photosynthesis
C) Transpiration
D) Fertilizer application
Answer: C) Transpiration
Explanation: Transpiration creates a negative pressure that pulls water upward through the xylem, driving the movement of water from roots to leaves.
Question 71:
Which of the following adaptations helps to prevent water loss during dry conditions?
A) Large leaf area
B) Thick cuticle
C) Open stomata
D) Abundant root hairs
Answer: B) Thick cuticle
Explanation: A thick cuticle minimizes water loss by creating a barrier to evaporation, helping plants retain moisture in dry conditions.
Question 72:
What is the term for the pressure that develops in the phloem due to the accumulation of sugars?
A) Hydrostatic pressure
B) Turgor pressure
C) Osmotic pressure
D) Root pressure
Answer: B) Turgor pressure
Explanation: Turgor pressure develops when sugars accumulate in the phloem, creating pressure that drives the flow of sap through the plant.
Question 73:
Which of the following elements is essential for the formation of chlorophyll in plants?
A) Nitrogen
B) Iron
C) Magnesium
D) Potassium
Answer: C) Magnesium
Explanation: Magnesium is a central component of chlorophyll, which is essential for photosynthesis.
Question 74:
The movement of water through plant tissues can be described as:
A) Unidirectional only
B) Bidirectional only
C) Both unidirectional and bidirectional
D) Random
Answer: A) Unidirectional only
Explanation: The movement of water in xylem is typically unidirectional, flowing from the roots to the leaves.
Question 75:
What physiological process occurs in the roots to maintain water uptake?
A) Photosynthesis
B) Respiration
C) Transpiration
D) Root pressure
Answer: D) Root pressure
Explanation: Root pressure is a physiological process that helps push water upward from the roots, particularly when transpiration rates are low.
Question 76:
Which factor would most likely decrease the rate of transpiration?
A) High temperature
B) High humidity
C) Strong winds
D) Bright sunlight
Answer: B) High humidity
Explanation: High humidity reduces the water vapor gradient between the leaf interior and the atmosphere, thus decreasing the rate of transpiration.
Question 77:
In which structure do guard cells regulate the opening and closing?
A) Stomata
B) Xylem
C) Phloem
D) Leaf epidermis
Answer: A) Stomata
Explanation: Guard cells surround stomata and control their opening and closing to regulate gas exchange and water loss.
Question 78:
The primary role of the endodermis in roots is to:
A) Absorb water
B) Control the movement of water and minerals into the vascular system
C) Store nutrients
D) Conduct photosynthesis
Answer: B) Control the movement of water and minerals into the vascular system
Explanation: The endodermis acts as a selective barrier, regulating what enters the vascular tissue from the soil.
Question 79:
Which type of plant root is specialized for climbing and support?
A) Taproot
B) Adventitious root
C) Fibrous root
D) Aerial root
Answer: D) Aerial root
Explanation: Aerial roots are specialized roots that grow above ground and can provide support and help the plant climb.
Question 80:
Which of the following processes allows for the passive movement of water across cell membranes?
A) Active transport
B) Facilitated diffusion
C) Osmosis
D) Bulk flow
Answer: C) Osmosis
Explanation: Osmosis is the passive movement of water across a semipermeable membrane from an area of low solute concentration to high solute concentration.
Question 81:
Which type of plant tissue is responsible for providing mechanical support and strength?
A) Parenchyma
B) Collenchyma
C) Sclerenchyma
D) Phloem
Answer: C) Sclerenchyma
Explanation: Sclerenchyma cells have thickened cell walls and provide mechanical support and rigidity to the plant.
Question 82:
In what part of the plant does the majority of nutrient assimilation occur?
A) Roots
B) Stems
C) Leaves
D) Flowers
Answer: C) Leaves
Explanation: Leaves are the primary site for photosynthesis and nutrient assimilation, where plants convert sunlight into energy.
Question 83:
What is the role of lignin in xylem?
A) Nutrient transport
B) Providing strength and support
C) Water absorption
D) Storage of carbohydrates
Answer: B) Providing strength and support
Explanation: Lignin is a complex organic polymer that strengthens the cell walls of xylem vessels, providing structural support to the plant.
Question 84:
Which of the following conditions would most likely cause stomatal closure?
A) High humidity
B) Low light intensity
C) Water stress
D) High temperature
Answer: C) Water stress
Explanation: Stomata close in response to water stress to minimize water loss, helping the plant conserve moisture.
Question 85:
What is the primary function of phloem parenchyma?
A) Conducting water
B) Storing and transporting nutrients
C) Providing mechanical support
D) Photosynthesis
Answer: B) Storing and transporting nutrients
Explanation: Phloem parenchyma cells are involved in the storage and transport of nutrients and play a supportive role in the phloem.
Question 86:
Which of the following processes primarily drives the upward movement of water in plants during the night?
A) Transpiration
B) Root pressure
C) Osmosis
D) Capillary action
Answer: B) Root pressure
Explanation: During the night, when transpiration is low, root pressure can push water upward through the xylem.
Question 87:
What is the main advantage of having a taproot system?
A) Increased nutrient absorption
B) Ability to reach deep water sources
C) Better stability
D) All of the above
Answer: D) All of the above
Explanation: A taproot system allows plants to access deeper water sources, enhances nutrient absorption, and provides greater stability.
Question 88:
In which plant part does the majority of transpiration occur?
A) Flowers
B) Stems
C) Roots
D) Leaves
Answer: D) Leaves
Explanation: The large surface area and abundance of stomata on leaves make them the primary site for transpiration.
Question 89:
Which of the following mechanisms is responsible for the movement of water in plants?
A) Active transport
B) Bulk flow
C) Simple diffusion
D) Facilitated diffusion
Answer: B) Bulk flow
Explanation: Bulk flow is the movement of water and solutes through xylem and phloem driven by pressure differences.
Question 90:
What do sieve tube elements lack that differentiates them from typical plant cells?
A) Nucleus
B) Cell wall
C) Cytoplasm
D) Chloroplasts
Answer: A) Nucleus
Explanation: Sieve tube elements are living cells that lack a nucleus, allowing for the efficient transport of nutrients in phloem.
Question 91:
What process helps to maintain the plant’s internal water balance?
A) Photosynthesis
B) Respiration
C) Transpiration
D) Fermentation
Answer: C) Transpiration
Explanation: Transpiration helps regulate the plant’s internal water balance by controlling water loss through stomata.
Question 92:
Which plant hormone is primarily responsible for cell elongation and growth?
A) Auxin
B) Cytokinin
C) Ethylene
D) Abscisic acid
Answer: A) Auxin
Explanation: Auxins promote cell elongation, allowing for growth in stems and roots.
Question 93:
The Casparian strip is located in which part of the root?
A) Epidermis
B) Cortex
C) Endodermis
D) Vascular cylinder
Answer: C) Endodermis
Explanation: The Casparian strip is a band of cell wall material in the endodermis that helps regulate the flow of water and minerals into the vascular tissue.
Question 94:
Which of the following best describes the role of mycorrhizae?
A) They provide structural support to plants.
B) They enhance nutrient and water absorption.
C) They protect plants from herbivores.
D) They are responsible for photosynthesis.
Answer: B) They enhance nutrient and water absorption.
Explanation: Mycorrhizae are symbiotic associations between fungi and plant roots that increase the surface area for water and nutrient absorption.
Question 95:
What is the main function of the root hairs?
A) Photosynthesis
B) Nutrient absorption
C) Mechanical support
D) Water storage
Answer: B) Nutrient absorption
Explanation: Root hairs increase the surface area of roots, enhancing the plant’s ability to absorb water and nutrients from the soil.
Question 96:
Which of the following adaptations would help a plant survive in a desert environment?
A) Large leaf area
B) Deep taproots
C) Open stomata during the day
D) Thin cuticle
Answer: B) Deep taproots
Explanation: Deep taproots allow plants to access water from deeper soil layers, making them better adapted to arid conditions.
Question 97:
What effect does increased temperature have on the rate of transpiration?
A) It decreases the rate of transpiration.
B) It has no effect on transpiration.
C) It increases the rate of transpiration.
D) It depends on humidity levels.
Answer: C) It increases the rate of transpiration.
Explanation: Higher temperatures increase the rate of evaporation of water from leaf surfaces, leading to an increase in transpiration.
Question 98:
The process by which nutrients are moved from the soil into the root cells is called:
A) Diffusion
B) Filtration
C) Active transport
D) Osmosis
Answer: C) Active transport
Explanation: Active transport allows roots to absorb essential nutrients from the soil against their concentration gradient.
Question 99:
Which of the following is a primary source of energy for the process of transpiration?
A) Sunlight
B) Wind
C) Soil moisture
D) Root pressure
Answer: A) Sunlight
Explanation: Sunlight provides the energy needed for photosynthesis, which in turn drives transpiration by creating a water vapor gradient.
Question 100:
Which of the following structures regulates water loss in plants?
A) Phloem
B) Xylem
C) Stomata
D) Cuticle
Answer: C) Stomata
Explanation: Stomata are openings on leaf surfaces that regulate gas exchange and water loss, playing a critical role in maintaining plant hydration.
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