Q1. Which tissue system forms the outermost covering of the plant body?
a) Vascular tissue system
b) Ground tissue system
c) Epidermal tissue system
d) Conducting tissue system
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Correct Answer: c) Epidermal tissue system
Explanation: The epidermal tissue system is the outermost protective layer of the plant body, analogous to the skin in animals. It is composed of epidermal cells, often with stomata and epidermal appendages like trichomes and root hairs. It protects the plant from water loss, mechanical injury and pathogens. Vascular and ground tissue systems are internal tissues.
Q2. Casparian strips are characteristic features of the:
a) Epidermis
b) Cortex
c) Pericycle
d) Endodermis
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Correct Answer: d) Endodermis
Explanation: Casparian strips are bands of suberin and lignin deposited in the radial and tangential walls of endodermal cells in roots. They are impermeable to water and ions, forcing water to move through the cell membranes of endodermal cells (symplast), thus regulating the entry of water and solutes into the vascular cylinder. Epidermis, cortex, and pericycle do not have Casparian strips.
Q3. Which of the following is NOT a simple tissue?
a) Parenchyma
b) Collenchyma
c) Sclerenchyma
d) Xylem
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Correct Answer: d) Xylem
Explanation: Xylem is a complex tissue because it is composed of different types of cells including tracheids, vessels, xylem parenchyma, and xylem fibers. Parenchyma, collenchyma, and sclerenchyma are simple tissues as they are composed of only one type of cells. Simple tissues perform basic functions while complex tissues perform specialized functions like conduction.
Q4. The main function of parenchyma tissue is:
a) Providing mechanical support
b) Conduction of water
c) Photosynthesis and storage
d) Conduction of food
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Correct Answer: c) Photosynthesis and storage
Explanation: Parenchyma cells are versatile and perform various functions including photosynthesis (in chlorenchyma), storage of food and waste materials, secretion, and wound healing. Collenchyma provides mechanical support, xylem conducts water, and phloem conducts food. Parenchyma is the most abundant and fundamental tissue in plants.
Q5. Which of the following cells provide mechanical strength to the plant parts and are thickened at the corners due to deposition of pectin and hemicellulose?
a) Parenchyma
b) Collenchyma
c) Sclerenchyma
d) Epidermal cells
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Correct Answer: b) Collenchyma
Explanation: Collenchyma cells are living mechanical tissues characterized by unevenly thickened cell walls at the corners due to deposition of cellulose, hemicellulose and pectin. They provide flexibility and tensile strength to young stems, petioles, and leaves, allowing them to bend without breaking. Sclerenchyma provides strength but cells are dead and uniformly thickened. Parenchyma is for storage and photosynthesis, and epidermal cells are for protection.
Q6. Sclereids are a type of:
a) Parenchyma
b) Collenchyma
c) Sclerenchyma
d) Epidermis
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Correct Answer: c) Sclerenchyma
Explanation: Sclereids are a type of sclerenchyma cell. They are short, isodiametric sclerenchyma cells with highly thickened, lignified walls. Sclereids are commonly found in fruit walls of nuts, pulp of fruits like guava, pear, and seed coats of legumes, providing hardness and grit. Fibers are another type of sclerenchyma, which are elongated.
Q7. Which of the following is a component of xylem tissue?
a) Sieve tubes
b) Companion cells
c) Tracheids
d) Phloem parenchyma
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Correct Answer: c) Tracheids
Explanation: Tracheids are elongated, lignified cells with tapered ends and pits in their walls, which are a key component of xylem tissue. They are primarily responsible for water conduction in vascular plants, especially in gymnosperms and pteridophytes. Sieve tubes, companion cells, and phloem parenchyma are components of phloem tissue, responsible for food conduction.
Q8. Vessels are characteristic features of xylem in:
a) Gymnosperms
b) Pteridophytes
c) Angiosperms
d) Bryophytes
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Correct Answer: c) Angiosperms
Explanation: Vessels are more advanced and efficient water-conducting elements found in xylem of angiosperms. They are long, cylindrical tube-like structures made up of vessel members connected end-to-end, with perforated end walls (perforation plates). Gymnosperms and pteridophytes lack vessels in xylem, primarily having tracheids. Bryophytes lack vascular tissues altogether.
Q9. Which of the following is a component of phloem tissue?
a) Tracheids
b) Vessels
c) Sieve tubes
d) Xylem fibers
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Correct Answer: c) Sieve tubes
Explanation: Sieve tubes are elongated, living conducting cells in phloem tissue, primarily responsible for translocation of food (sugars) from leaves to other parts of the plant. They are characterized by perforated end walls called sieve plates. Tracheids, vessels, and xylem fibers are components of xylem, not phloem.
Q10. Companion cells are closely associated with:
a) Tracheids
b) Vessels
c) Sieve tubes
d) Xylem parenchyma
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Correct Answer: c) Sieve tubes
Explanation: Companion cells are specialized parenchyma cells closely associated with sieve tubes in phloem of angiosperms. They are connected to sieve tubes through pits and are believed to help in maintaining the pressure gradient in sieve tubes and loading/unloading of sugars. Tracheids, vessels, and xylem parenchyma are related to xylem, not phloem.