51. Mesophyll cells are:
Answer: C. thin-walled living cells between the two epidermal layers
Biology Class 11 Unit 9: Diversity in Plant Functions MCQs
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52. Dicot leaves have how many layers of mesophyll?
Answer: B. Two: palisade and spongy
53. Palisade mesophyll consists of:
Answer: B. tightly packed elongated cells without spaces
54. Spongy mesophyll is located:
Answer: B. next to the lower epidermis
55. Leaves with distinct palisade and spongy layers are:
Answer: C. bifacial (dorsiventral)
56. Monocot leaves are:
Answer: C. isobilateral (monofacial) with only spongy mesophyll
57. Stomata are formed by two:
Answer: B. kidney or bean-shaped guard cells
58. In bifacial leaves more stomata are found in the:
Answer: B. lower epidermis
59. Isobilateral leaves have stomata:
Answer: C. evenly distributed on both surfaces
60. Transpiration is the loss of water:
Answer: B. as vapour from aerial parts, primarily through stomata
61. The movement of water in and out of cells by osmosis. Water entering a cell is:
Answer: B. endosmosis
62. Water leaving a cell is called:
Answer: B. exosmosis
63. Water potential is denoted by:
Answer: C. psi w
64. The water potential of pure water is:
Answer: C. zero
65. The water potential of cells and solutions is:
Answer: B. less than zero (negative)
66. The equation of water potential is:
Answer: B. psi w = psi s + psi p
67. Solutes ... water potential:
Answer: B. lower
68. Solute potential is also called:
Answer: B. osmotic potential
69. Solute potential in distilled water is:
Answer: C. zero
70. Pressure potential is:
Answer: B. an increase in water potential due to pressure greater than atmospheric
71. Water moves from:
Answer: B. higher to lower water potential
72. The order of water potential from soil to atmosphere is:
Answer: B. soil > root > stem > leaf > atmosphere
73. The Casparian strip is made of:
Answer: C. suberin and lignin
74. The Casparian strip is present in the:
Answer: C. endodermis
75. The Casparian strip blocks the:
Answer: B. apoplast pathway
76. The apoplast is the system of:
Answer: C. adjacent cell walls
77. The pathway through cytoplasmic connections (plasmodesmata) is the:
Answer: B. symplast pathway
78. In the vacuolar pathway water moves:
Answer: C. from vacuole to vacuole crossing membranes and tonoplast
79. Water enters the root from the soil through:
Answer: B. root hairs by osmosis
80. The correct path of water in the root is:
Answer: B. epidermis, cortex, endodermis, pericycle, xylem
81. Xylem conducts mainly:
Answer: B. water and minerals
82. Phloem conducts:
Answer: B. organic food from leaves upward and downward
83. The four cell types of xylem are:
Answer: B. tracheids, vessel elements, xylem fibres and xylem parenchyma
84. The only living cells of xylem are:
Answer: D. xylem parenchyma
85. Tracheids are:
Answer: B. dead, elongated cells with tapering ends and lignified walls
86. Xylem vessels are found only in:
Answer: C. angiosperms
87. Xylem vessels are formed by:
Answer: B. end to end fusion of vessel elements
88. Xylem fibres mainly give:
Answer: C. mechanical support
89. The phloem consists of:
Answer: B. three living cells (sieve tube elements, companion cells, parenchyma) and one dead cell (phloem fibre)
90. Sieve tube elements lack:
Answer: C. nuclei at maturity
91. The perforated partition between two sieve tube elements is the:
Answer: B. sieve plate
92. The activity of sieve tube elements is controlled by:
Answer: B. adjacent companion cells
93. Companion cells provide:
Answer: B. energy to sieve tube elements
94. Phloem fibres are:
Answer: B. thick-walled supporting cells
95. The upward movement of water in xylem is called:
Answer: B. ascent of sap
96. The most accepted theory of ascent of sap is the:
Answer: B. TACT theory
97. TACT stands for:
Answer: B. Transpiration pull, Adhesion, Cohesion, Tension
98. The evaporation of water from leaves develops:
Answer: B. transpiration pull
99. Attraction between water molecules and xylem walls is:
Answer: B. adhesion
100. Attraction among water molecules due to hydrogen bonds is:
Answer: B. cohesion
About Biology Class 11 Unit 9 MCQs (Federal Board)
These 278 Biology MCQs cover Class 11 Unit 9: Diversity in Plant Functions of the Federal Board (FBISE) HSSC-I (1st Year / Class 11) syllabus. They are SLO-based MCQs as per the new pattern for FBISE exams. Each question has four options and the correct answer is shown, so you can practise for the annual examination and find the topics you still need to revise. The questions are split over 6 pages of 50. Use the Print button to save this chapter as a PDF.