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Q.1. Given below are two statements: (NEET 2022)
Statement I: The primary CO2 acceptor in C4 plants is phosphoenolpyruvate and is found in the mesophyll cells.
Statement II: Mesophyll cells of C4 plants lack RuBisCo enzyme.
In the light of the above statements, choose the correct answer from the options given below:
(a) Both Statement I and Statement II are incorrect
(b) Statement I is correct but Statement II is incorrect
(c) Statement I is incorrect but Statement II is correct
(d) Both Statement I and Statement II are correct
Phosphoenolpyruvate or PEP is the 3C compound and acts as the primary carbon dioxide acceptor in the mesophyll cells of C4 plants, leading to the formation of OAA, C4 acid. Ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO) is an enzyme found in the mesophyll cells present within the C3 plants. In C4 plants, this enzyme is found in the bundle sheath cells.
Q.2. In old trees the greater part of secondary xylem is dark brown and resistant to insect attack due to: (NEET 2022)
(a) secretion of secondary metabolities and their deposition in the lumen of vessels.
(b) deposition of organic compounds like tannins and resins in the central layers of stem.
(c) deposition of suberin and aromatic substances in the outer layer of stem.
(d) deposition of tannins, gum, resin and aromatic substances in the peripheral layers of stem.
(e) presence of parenchyma cells, functionally active xylem elements and essential oils.
Choose the correct answer from the options given below:
(a) (c) and (d) Only
(b) (d) and (e) Only
(c) (b) and (d) Only
(d) (a) and (b) Only
In old trees, the greater part of secondary xylem is dark brown due to deposition of organic compounds like tannins, resins, oils, gums, aromatic substances and essential oils in the central or innermost layers of the stem. These substances make it hard, durable and resistant to the attacks of microorganisms and insects. This region comprises dead elements with highly lignified walls and is called heartwood.
Q.3. Read the following statements about the vascular bundles: (NEET 2022)
(a) In roots, the xylem and phloem in a vascular bundle are arranged in an alternate manner along the different radii.
(b) Conjoint closed vascular bundles do not possess cambium.
(c) In open vascular bundles, cambium is present in between xylem and phloem
(d) The vascular bundles of dicotyledonous stem possess endarch protoxylem
(e) In the monocotyledonous root, usually there are more than six xylem bundles present
Choose the correct answer from the options given below:
(a) (b), (c), (d) and (e) Only
(b) (a), (b), (c), (d) and (e)
(c) (a), (c), (d) and (e) Only
(d) (a), (b) and (d) Only
The vascular system consists of complex tissues, the phloem and the xylem. The xylem and phloem together constitute vascular bundles. In roots, xylem and phloem in a vascular bundle are arranged in an alternate manner along the different radii the arrangement is called radial. Conjoint closed vascular bundles do not possess cambium. In open vascular bundles, cambium is present in between xylem and phloem. The vascular bundles of dicotyledonous stem possess endarch protoxylem. In monocotyledonous root, usually there are more than six xylem bundles present.
Q.4. Identify the correct set of statements: (NEET 2022)
(a) The leaflets are modified into pointed hard thorns in Citrus and Bougainvillea
(b) Axillary buds form slender and spirally coiled tendrils in cucumber and pumpkin
(c) Stem is flattened and fleshy in Opuntia and modified to perform the function of leaves
(d) Rhizophora shows vertically upward growing roots that help to get oxygen for respiration
(e) Subaerial growing stem in grasses and strawberry help in vegetative propagation
Choose the correct answer from the options given below:
(a) (a) and (d) Only
(b) (b), (c), (d) and (e) Only
(c) (a), (b), (d) and (e) Only
(d) (b) and (c) Only
The thorn is a hard, straight and pointed structure. In Citrus and Bougainvillea the axillary bud is modified into a thorn. Cucumber and pumpkins have long slender and coiled stem tendrils which develop from axillary buds. Stem is flattened and fleshy in Opuntia and modified to perform photosynthesis. Rhizophora shows vertically upward growing roots which is known as pneumatophore help to get oxygen for respiration. Subaerially growing stems in grasses and strawberry help in vegetative propagation.
Q.5. The anatomy of springwood shows some peculiar features. Identify the correct set of statements about springwood. (NEET 2022)
(a) It is also called as the earlywood
(b) In spring season cambium produces xylem elements with narrow vessels
(c) It is lighter in colour
(d) The springwood along with autumnwood shows alternate concentric rings forming annual rings
(e) It has lower density
Choose the correct answer from the options given below:
(a) (a), (c), (d) and (e) only
(b) (a), (b) and (d) only
(c) (c), (d) and (e) only
(d) (a), (b), (d) and (e) only
The true statements are:
1. It is also called as the early wood.
2. In spring season cambium produces xylem elements with wider vessels.
3. Spring wood is lighter in colour
4. The spring wood along with autumn wood shows alternate concentric rings forming annual rings.
5. It has lower density
Q.6. Match List I with List II (NEET 2021)
Select the correct answer from the options given below.
(a) (b) (c) (d)
(a) (i) (ii) (iii) (iv)
(b) (iii) (ii) (iv) (i)
(c) (ii) (iv) (i) (iii)
(d) (iv) (iii) (ii) (i)
- Growth in plants is largely restricted to specialised regions of active cell division called meristems (Gk. meristos: divided).
- Permanent tissues having all cells similar in structure and function are called simple tissues.
- Permanent tissues having many different types of cells are called complex tissues.
- The sclereids are spherical, oval or cylindrical, highly thickened dead cells with very narrow cavities (lumen).
- The vascular system consists of complex tissues, the phloem and the xylem.The xylem and phloem together constitute vascular bundles
Q.7. Match List-I with List-II. (NEET 2021)
Choose the correct answer from the options given below.
(a) (b) (c) (d)
(a) (ii) (iii) (iv) (i)
(b) (iv) (ii) (i) (iii)
(c) (iv) (i) (iii) (ii)
(d) (iii) (i) (iv) (ii)
- Hence, sooner or later, another meristematic tissue called cork cambium or phellogen develops, usually in the cortex region.
- The outer cells differentiate into cork or phellem while the inner cells differentiate into secondary cortex or phelloderm.
- The cork is impervious to water due to suberin deposition in the cell wall.
- Lenticels permit the exchange of gases between the outer atmosphere and the internal tissue of the stem.
Q.8. Select the correct pair. (NEET 2021)
(a) Cells of medullary rays that form part of a cambial ring - Interfascicular cambium
(b) Loose parenchyma cells rupturing the epidermis and forming a lens-shaped opening in the bark - Spongy parenchyma
(c) Large colourless empty cells in the epidermis of grass leaf - Subsidiary cells
(d) In dicot leaves, vascular bundles are surrounded tissue by large thick-walled cells - Conjunctive tissue
The cells of medullary rays, adjoining these intrafascicular cambium become meristematic and form the interfascicular cambium.
Q.9. Identify the incorrect statement. (NEET 2020)
(a) Sapwood is the innermost secondary xylem and is lighter in colour.
(b) Due to the deposition of tannins, resins, oils etc., the heartwood is dark in colour.
(c) Heartwood does not conduct water but gives mechanical support.
(d) Sapwood is involved in the conduction of water and minerals from the root to the leaf.
In a large tree, only the outer secondary xylem (sapwood) serves in water conduction, while the inner part (heartwood) is composed of dead but structurally strong secondary xylem and is darker in colour due to the deposition of tannins, resins and oils.
Q.10. The transverse section of a plant shows the following anatomical features:
(i) a Large number of scattered vascular bundles surrounded by bundle sheath.
(ii) Large conspicuous parenchymatous ground tissue.
(iii) Vascular bundles conjoint and closed.
(iv) Phloem parenchyma absent.
Identify the category of plant and its part: (NEET 2020)
(a) Dicotyledonous stem
(b) Dicotyledonous root
(c) Monocotyledonous stem
(d) Monocotyledonous root
All these anatomical features are showing that plant is monocotyledonous stem so option 3 is correct. The monocot stem has vascular bundles near the outside edge of the stem. Vascular bundles are scattered in parenchymatous ground tissue. There is no pith region in monocots. The vascular bundles are closed as they do not have cambium in it
Q.11. Grass leaves curl inwards during very dry weather. Select the most appropriate reason from the following. (NEET 2019)
(a) Tyloses in vessels
(b) Closure of stomata
(c) Flaccidity of bulliform cells
(d) Shrinkage of air spaces in the spongy mesophyll
In grasses, certain adaxial epidermal cells along the veins modify themselves into large, empty, colourless cells. These are called bulliform cells. When the bulliform cells in the leaves have absorbed water and arc turgid, the leaf surface is exposed. When they are flaccid due to water stress, they make the leaves curl inwards to minimise water loss.
Leaves Curl inwards
Q.12. Phloem in gymnosperms lacks (NEET 2019)
(a) Both sieve tubes and companion cells
(b) Albuminous cells and sieve cells
(c) Sieve tubes only
(d) Companion cells only.
In gymnosperms, phloem is without companion cells and sieve tubes.
Q.13. Which of the statements given below is not true about the formation of annual rings in trees? (NEET 2019)
(a) Annual rings are not prominent in trees of temperate regions.
(b) Annual ring is a combination of springwood and autumn wood produced in a year.
(c) Differential activity of cambium causes light and dark bands of tissue-early and latewood respectively.
(d) Activity of cambium depends upon variation in climate.
The activity of cambium is under the control of many physiological and environmental factors. In temperate regions, the climatic conditions are not uniform throughout the year. In the spring season, cambium is very active and produces a large number of xylary elements having vessels with wider cavities. The wood formed during this season is called spring wood or early wood.Annual Rings
In winter, the cambium is less active and forms fewer xylary elements that have narrow vessels and this wood is called autumn wood or late wood. The spring wood is lighter in colour and has a lower density whereas the autumn wood is darker and has a higher density. The two kinds of woods that appear as alternate concentric rings, constitute an annual ring.
Q.14. In the dicot root, the vascular cambium originates from- (NEET 2019)
(a) Tissue located below the phloem bundles and a portion of pericycle tissue above protoxylem.
(b) Cortical region.
(c) Parenchyma between endodermis and pericycle.
(d) Intrafascicular and interfascicular tissue in a ring.
Ans. aTissue located below the phloem bundles and a portion of pericycle tissue above protoxylem.
Q.15. Regeneration of damaged growing grass following grazing is largely due to (NEET 2019)
(a) Lateral meristem
(b) Apical meristem
(c) Intercalary meristem
(d) Secondary meristem
Regeneration of damaged growing grass following grazing is largely due to Intercalary meristem. Intercalary meristem occur in grass and regenerate the part removed by grazing herbivores.
Q.16. Stomata in grass leaf are (NEET 2018)
(a) Dumb-bell shaped
Grass being a monocot, has dumb-bell shaped guard cells. Guard cells are generally bean-shaped or kidney-shaped in dicots.
Q.17. Secondary xylem and phloem in dicot stem are produced by (NEET 2018)
(a) Apical meristems
(b) Vascular cambium
(d) Axillary meristems
- Vascular cambium is a type of lateral meristem that produces secondary tissues (xylem and phloem) during secondary growth.
It is produced by two types of meristem: intrafascicular cambium (primary meristem occurring as strip in vascular bundles) and interfascicular cambium (secondary meristem which develops from permanent cells of medullary rays which occur at the level of intrafascicular strips).
The cells of vascular cambium are of two types : fusiform initials which produce secondary xylem towards outside and secondary phloem towards inner side and ray initials which give rise to vascular rays.
Q.18. Casparian strips occur in (NEET 2018)
A casparian strip is a band of thickening present on the radial and tangential walls of the endodermis. It is made up of both suberin and lignin.
Q.19. Plants having little or no secondary growth are (NEET 2018)
(b) Deciduous angiosperms
Monocots (e.g., grasses) lack secondary growth, as they lack lateral meristem viz. vascular cambium and cork cambium. In the case of conifers (e.g., Pinus) and cycads (e.g., Cycas) vascular tissues are arranged into vascular bundles just like angiosperms, they are open so secondary growth is common.
Q.20. The vascular cambium normally gives rise to (NEET 2017)
(a) Primary phloem
(b) Secondary xylem
Cells of vascular cambium divide periclinal both on the outer and inner sides to form secondary permanent tissues, i.e., secondary xylem and secondary phloem.
Q.21. Root hair develops from the region of (NEET 2017)
(b) Root cap
(c) Meristematic activity
Root hair are lateral tubular outgrowths that develop from the outer cells of the zone of maturation or root hair zone.
Q.22. Which of the following is made up of dead cells? (NEET 2017)
(d) Xylem parenchyma
The phellem or cork consists of dead and compactly arranged rectangular cells that possess suberised cell walls.
Q.23. Identify the wrong statement in the context of heartwood. (NEET 2017)
(a) It is highly durable.
(b) It conducts water and minerals efficiently
(c) It comprises dead elements with highly lignified walls.
(d) Organic compounds are deposited in it.
Heartwood is the non-functional part of the secondary xylem, hence, it does not conduct water and minerals.
Q.24. Cortex is the region found between (NEET 2016)
(a) Epidermis and stele
(b) Pericycle and endodermis
(c) Endodermis and pith
(d) Endodermis and vascular bundle.
- Cortex is the ground tissue present below the epidermis.
It surrounds the central cylinder and the endodermis lines the outermost layer of the cylinder.
So, the region between epidermis and stele is cortex.
Q.25. The balloon-shaped structures called tyloses (NEET 2016)
(a) Originate in the lumen of vessels
(b) Characterise the sapwood
(c) Are extensions of xylem parenchyma cells into vessels
(d) Are linked to the ascent of sap through xylem vessels.
- Tyloses are balloon-like extensions of parenchyma cells that protrude into the lumen of a neighbouring xylem vessel or tracheid through a pit in the cell wall.
Tyloses form most commonly in older woody tissue, possibly in response to injury, they may eventually block the vessels and thus prevent the spread of fungi and other pathogens within the plant.
Tyloses may become filled with tannins, gums, pigments, etc., giving heartwood its dark colour, and their walls can remain thin or become lignified.
Q.26. Specialized epidermal cells surrounding the guard cells are called (NEET 2016)
(a) Bulliform cells
(c) Complementary cells
(d) Subsidiary cells.
- The leaf and stem epidermis of the plant is covered with pores called stomata.
Each stomata is surrounded by a pair of specialised epidermal cells known as guard cells which are in some cases further surrounded by another category of less modified epidermal cells known as subsidiary cells which provide support to the guard cells.
Q.27. Transmission tissue is the characteristic feature of (NEET 2015)
(a) Solid style
(b) Dry stigma
(c) Wet stigma
(d) Hollow style
A solid style has transmission tissue that has large intercellular spaces. It allows the growth of pollen tubes in pistils.
Q.28. A major characteristic of the monocot root is the presence of (NEET 2015)
(a) Scattered vascular bundles
(b) Vasculature without cambium
(c) Cambium sandwiched between phloem and xylem along the radius
(d) Open vascular bundles
Monocot root shows radial and closed vascular bundle (xylem & phloem).
Q.29. In a ring girdled plant: (NEET 2015)
(a) The root dies first
(b) The shoot and root die together
(c) Neither root nor shoot will die
(d) The shoot dies first
In a ring girdled plants roots die first due to damage of phloem causing inhibition of translocation of food.
Q.30. Vascular bundles in monocotyledons are considered closed because: (NEET 2015)
(a) Cambium is absent
(b) There are no vessels with perforations
(c) Xylem is surrounded all around by phloem
(d) A bundle sheath surrounds each bundle
Vascular bundles in monocotyledons are considered closed due to the absence of cambium.
Q.31. Read the different components from (A) to (D) in the list given below and tell the correct order of the components with reference to their arrangement from the outer side to the inner side in a woody dicot stem. (NEET 2015)
(A) Secondary cortex
(C) Secondary phloem
The correct order is:
(a) (A), (B), (D), (C)
(b) (D), (A), (C), (B)
(c) (D), (C), (A), (B)
(d) (C), (D), (B), (A)
The correct sequence from outer side to inner side in a woody dicot stem is as follows:
Phellem →Secondary cortex → Secondary phloem → Wood , [(d) → (a) → (c) → (b)].
Q.32. You are given a fairly old piece of dicot stem and a dicot root. Which of the following anatomical structures will you use to distinguish between the two? (NEET 2014)
(a) Secondary xylem
(b) Secondary phloem
(d) Cortical cells
The anatomically fairly old dicotyledonous root is distinguished from the dicotyledonous stem by position of protoxylem. In dicot root the protoxylem is located near the periphery of the vascular cylinder while in dicot stem the protoxylem is located near the centre of vascular bundle i.e., the xylem is endarch.
Q.33. Tracheids differ from other tracheary elements in: (NEET 2014)
(a) Having Casparian strips
(b) Being imperforate
(c) Lacking nucleus
(d) Being lignified
The walls of vessels (tracheary elements) are lignified and less thick than tracheids. The lumen is wider. Vessels differ from tracheids in being cell fusions arising through the dissolution of end walls.