- The water-conducting cells in xylem that have pits but no perforations are:
a) Tracheids
b) Vessels
c) Companion cells
d) Sieve tubes
Answer: a) Tracheids
Explanation: Tracheids are water-conducting cells in xylem that have tapered ends and are connected through pits, but they do not have perforations like vessel elements.
- Which structure provides protection to the root tip as it grows through the soil?
a) Root hair
b) Endodermis
c) Root cap
d) Pericycle
Answer: c) Root cap
Explanation: The root cap protects the growing root tip as it pushes through the soil. It also secretes mucilage to lubricate the passage of the root.
- What is the main function of the endodermis in the root?
a) Gas exchange
b) Protection from herbivores
c) Control of water and nutrient entry into the xylem
d) Support
Answer: c) Control of water and nutrient entry into the xylem
Explanation: The endodermis contains the Casparian strip, which regulates the passage of water and nutrients into the xylem, ensuring selective uptake of essential minerals.
- The secondary growth in plants leads to the formation of:
a) Epidermis
b) Secondary xylem and phloem
c) Primary xylem and phloem
d) Apical meristem
Answer: b) Secondary xylem and phloem
Explanation: Secondary growth, which is caused by the activity of the vascular cambium, leads to the formation of secondary xylem (wood) and secondary phloem, increasing the girth of stems and roots.
- Which plant tissue is most commonly involved in photosynthesis?
a) Xylem
b) Phloem
c) Mesophyll
d) Collenchyma
Answer: c) Mesophyll
Explanation: Mesophyll cells, found in the leaf between the upper and lower epidermis, contain chloroplasts and are primarily responsible for photosynthesis.
- Which meristem is responsible for the production of secondary vascular tissue?
a) Apical meristem
b) Cork cambium
c) Vascular cambium
d) Intercalary meristem
Answer: c) Vascular cambium
Explanation: The vascular cambium is responsible for the production of secondary xylem and secondary phloem, which contribute to the thickening of the plant stem and root during secondary growth.
- Which tissue in plants provides mechanical support and consists of thickened, lignified cells?
a) Parenchyma
b) Collenchyma
c) Sclerenchyma
d) Xylem
Answer: c) Sclerenchyma
Explanation: Sclerenchyma consists of dead cells with thick, lignified walls that provide mechanical support and strength to the plant body.
- The tissue that connects xylem and phloem in a vascular bundle is called:
a) Pericycle
b) Cambium
c) Endodermis
d) Parenchyma
Answer: b) Cambium
Explanation: The cambium, particularly the vascular cambium, is a meristematic tissue that lies between xylem and phloem in vascular bundles and is responsible for producing secondary xylem and phloem.
- The secondary xylem formed in roots during secondary growth is produced by:
a) Apical meristem
b) Lateral meristem
c) Vascular cambium
d) Pericycle
Answer: c) Vascular cambium
Explanation: The vascular cambium produces secondary xylem and secondary phloem during secondary growth, increasing the thickness of roots and stems.
- In dicot roots, the vascular bundles are:
a) Collateral
b) Bicollateral
c) Radial
d) Conjoint
Answer: c) Radial
Explanation: In dicot roots, the vascular bundles are arranged in a radial manner, with xylem and phloem located on different radii.
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