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CBSE Questions for Class 11 Medical Biology Anatomy Of Flowering Plants Quiz 14 - MCQExams.com
CBSE
Class 11 Medical Biology
Anatomy Of Flowering Plants
Quiz 14
Cambial ring in dicot root is initially
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Wavy
0%
Circular
0%
Discontinuous
0%
Crescentric
Explanation
A. Wavy
EXPLANATION: Vascular cambium of dicot root originates from the pericycle tissue located just below the phloem bundles. A part of pericycle tissue above the protoxylem forms complete wavy ring. So the cambial ring in dicot root is initially wavy.
In dicot stem, cork cambium is formed by dedifferentiation of
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Epidermal cells
0%
Endodermal cells
0%
Cortical cells
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Pericycle cells
Tissues form organs.
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True
0%
False
Explanation
Tissue is
a group of cells that have a similar structure
and that function together as a unit. A group of tissues forms an organ. Organs form an organ system. Different organ systems make up the complete individual.
So, the statement is true.
Interfascicular cambium in dicot root is
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Formed by redifferentiation of medullary ray cells
0%
Formed by dedifferentiation of medullary cells
0%
Formed by dedifferentiation of medullary cell
0%
absent
Find out incorrect sentence
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Parenchymatous tissues have intercellular spaces
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Collenchymatous tissues are irregularly thickened at corners
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Apical and intercalary meristems are permanent tissues
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Meristematic tissues, in its early stage, lack vacuoles
Explanation
Meristematic tissues are not permanent tissues as permanent tissues do not divide after differentiation. Examples, of permanent tissue collenchyma, parenchyma, xylem, phloem etc
Apical and intercalary meristems are primary meristems responsible for vertical growth of the plant.
So, the incorrect statement is '
Apical and intercalary meristems are permanent tissues'
A conjoint and open vascular bundle will be observed in the transverse section of-
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Monocot root
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Monocot stem
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Dicot root
0%
Dicot stem
Explanation
$$\textbf{Correct option:}$$
(D)
$$\textbf{Explanation for correct option:}$$
$$\bullet$$
Vascular bundle in which xylem and phloem lie on the same radii in such a position that xylem lies inwards and phloem outwards is called Conjoint and collateral vascular bundle.
$$\bullet$$
When it possess a strip of cambium between xylem and phloem then it is of open type. Such vascular bundles because of the presence of cambium has the ability to form secondary xylem and phloem tissues.
$$\bullet$$ Conjoint, collateral and open vascular bundles are the characteristic of dicot stem.
$$\bullet$$ Hence the correct option is (D)
Veins of leaves have both xylem and phloem
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0%
True
0%
False
Explanation
True.
Veins of the leaves contain conjoint and colateral vascular bundles, hence contain both xylem and phloem.
Intrastelar ground tissue includes:
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Epidermis, hypodermis and cortex
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Cortex, Medullary rays and endodermis
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Pericycle, medullary rays and pith
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Xylem, Phloem and cambium
Explanation
Stele is demarcated from the cortex by the endodermis. The stele thus comprises of the pericycle, the rays separating the vascular bundles called the medullary rays and the central pith. All these cells are parenchymatous and tend to fill in the spaces between the vascular bundles, the central region of the stem or the root and the space between the vascular bundle and the pericycle. Hence, called the ground tissue.
So, the correct answer is '
Pericycle, medullary rays and pith'
If we take the growing roots of an onion and cut out its tips, the roots will no longer grow, because we have cut out the:
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Lateral meristem
0%
Apical meristem
0%
Intercalary meristem
0%
Cambium
Explanation
D. Apical meristem
Solution : Growing roots of an onion has apical meristem which are the growing regions of the plants. This if cut stops the growth of the plants in that region.
So the correct answer is " Apical meristem".
Consider the following statements.
A. In a dicot root, the vascular bundles are collateral and endarch.
B. The inner most layer of cortex in a dicot root is endodermis.
C. In a dicot root, the phloem masses are separated from the xylem by parenchymatous cells that are known as the conjunctive tissue.
Of these statements given above
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A is true, but B and C are false
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B is true, but A and C are false
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A is false, but B and C are true
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C is false, but A and C are true
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C is true, but A and B are false
Explanation
In a dicot root, the vascular bundles are open and endarch. In endarch condition, the protoxylem is directed towards the center and metaxylem elements towards the periphery.
The endodermis is the innermost part of the cortex.
Conjunctive tissue is a group of parenchymatous cells that are present between the xylem and phloem in dicot roots.
So, the correct answer is option C.
Tracheids and vessels are associated with
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Phloem of angiosperms
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Xylem of angiosperms
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Xylem of gymnosperms
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Phloem of gymnosperms
Explanation
Tracheids and vessels are associated with xylem of angiosperms.
Xylem tracheid occurs in all plants included lower plant, gymnosperms, and angiosperms. Angiosperms have another kind of xylem, that is xylem vessel, which is better in transport water, but tracheids still remain in angiosperms.
So, the correct answer is option B.
A long tree has several branches. The tissue that helps in the side ways conduction of water in the branch is
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Collenchyma
0%
Xylem parenchyma
0%
Parenchyma
0%
Xylem vessels
Explanation
Xylem is a complex permanent tissue. It is composed of xylem tracheids, vessels, fibres, and parenchyma. Xylem parenchyma helps in sideways conduction. Xylem vessels and tracheids are responsible for vertical conduction of water.
So, the correct answer is option B.
Trees at sea do not have annual rings because
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Soil is sandy
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There is climatic variation
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There is no marked climatic variation
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There is enough moisture in the atmosphere
Explanation
Because in sea shore area being isothermal zones , temperature is constant throughout the year' so their
will be no annual ring formation.
Cell wall in cork is impervious to water and gases due to presence of
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0%
Lignin
0%
Pectin
0%
Suberin
0%
Cellulose
Explanation
Suberin is a waxy substance, similar to cutin, present in the thickened cell walls of many trees and shrubs, particularly in cork tissues.
The outer cork cambium gradually loses their protoplast and become dead and their cell walls become suberized.
The deposition of suberin (suberization) provides a water protective layer.
Thus, the correct answer is option C.
Which cell does not have perforated cell wall?
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Tracheids
0%
Companion cells
0%
Sieve tubes
0%
None of these
Explanation
Xylem elements contain the tracheids and vessels. These help in the conduction of water. They are long tube-like structures with partially or completely dissolved walls to form water pipes (in vessels) and pits in the cell wall (in tracheids) for conducting water.
Sieve tubes are slender tube-like structures with their end walls perforated by numerous pores and are called sieve plates. They are phloem elements and are the main food conducting elements.
Companion cells possess a perforated cell wall.
Therefore, the correct answer is option A.
In monocot roots, which types of vascular bundles are found?
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Collateral, conjoint and closed
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Radial with exarch xylem
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Bicollateral, conjoint and closed
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Radial with endarch xylem
Explanation
In monocot roots, the protoxylem elements face pericycle between xylem and phloem elements, parenchyma cells are present constituting conjunctive tissue. This tissue does not become meristematic. Vascular bundles are usually more than six in number. Hence, the vascular bundle is radial with exarch xylem.
Thus, the correct answer is option B.
Vessels are found in
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Ephedra
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All gymnosperms
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Funaria
0%
None of the above
Explanation
Gnetophytes are the most distinctive of gymnosperms because of their similarities with angiosperms. They have flower-like compound strobili. They have vessels in secondary xylem. They have double fertilization (However, this double fertilization does not result in the formation of endosperm. Instead, the diploid cell from fertilization by the second sperm disintegrates). There are 3 clearly defined, morphologically dissimilar genera of these gymnosperms: Ephedra (40 spp.), Gnetum (30 spp.), and Welwitschia (1 sp). One feature they all share, in addition to being gymnosperms, is the presence of vessel elements in their wood, a cell type absent in other gymnosperms.
So, the correct answer is option A.
Which of the following is a correct sequence of layers in typical monocot root (from outer surface to inside)?
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Pericycle, cortex, endodermis, epiblema
0%
Epiblema, endodermis, cortex, pericycle
0%
Epiblema, cortex, endodermis, pericycle
0%
Epiblema, pericycle, cortex, endodermis
Explanation
The vascular bundles of monocot root are polyarch, radial, exarch, and closed. The external protective layer is called the epiblema or piliferous layer. The region inner to epiblema is called the cortex and it is homogenous.
The innermost cortical layer is called the endodermis. Its cells are barrel-shaped and are closely packed. Inner to endodermis, one or two layers of parenchyma are present, constituting the pericycle.
So, the correct answer is option C.
Which of the following is used to obtain commercial cork?
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Quercus
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Salix
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Betula
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Morus
Explanation
Commercial cork is obtained
from the bark of
Quercus suber
(
cork
oak), native to and cultivated in the Mediterranean region
, which is endemic to southwest Europe and northwest Africa. Cork is composed of suberin, a hydrophobic substance, and because of its impermeable, buoyant, elastic and fire retardant properties, it is used in a variety of products, the most common of which is for wine stoppers.
So, the correct answer is '
Quercus'
Bicollateral vascular bundles are found in
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Malvaceae
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Cucurbitaceae
0%
Liliaceae
0%
Poaceae
Explanation
Correct Option:
B
E
xplanation:
Bicollateral tube bundles are visible in the members of
Cucurbitaceae.
It is a form of conjoint vascular tissue in the stem that has only 1 strand of vascular tissue and 2 strands of phloem. In such a vascular bundle, the phloem is present on the outer side and the inner side of the xylem.
It is an open vascular bundle usually found in the stems of
Cucurbita
or
Cephalandra plants.
Hence, Bicollateral tube bundles are found in
Cucurbitaceae(dicot family).
The cambium located in between xylem and phloem in dicot stem is
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Interfascicular
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Intrafascicular
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Both A and B
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None of the above
Explanation
The cambium located in between xylem and phloem in dicot stem is intrafascicular. Itrafascicular cambium is primary meristem that develops from the procambium of the stem apex. It is located inside the open vascular bundles, between phloem and xylem patches. During secondary growth, the derivatives are only secondary phloem and secondary xylem.
Which one of the following is correct match?
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Monarch -
Nicotiana tabacum
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Diarch
- Trapa natans
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Triarch -
Pisum sativum
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Tetrarch -
Ricinus communis
Explanation
The first xylem formed is called as protoxylem and later ones are called as metaxylem. The number of protoxylem groups in root, i.e., whether one, two, three, etc., is expressed in terms as monarch, diarch, triarch respectively.
Nicotiana tabacum
is diarch.
Trapa natans
is monarch.
Ricinus communis
is pentarch.
Pisum sativum
is triarch.
Thus, the correct answer is option C.
The concept of four distinct zone of tissue builders on the root apex is called as
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Tunica-Corpus theory
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Dermatogen theory
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Meristem theory
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Histogen theory
Explanation
Tunica-Corpus theory is proposed by Schmidt for organisation of shoot apex. According to this theory, shoot apex can be differentiated in two regions as a central core and tunica which surrounds the central core. Central core contain large cells and divide irregularly and result in volume growth. However, tunica cells are smaller which divide to form surface layer.
Dermatogen is a layer not a theory.
Meristem is a layer not a theory.
Histogen theory is proposed by Hanstein. According to h
istogen theory, there are three zones as dermatogen, periblem and pleurome in shoot and root apical meristem. These three zones are considered as histogens or tissue builders. Each zone performs distinct functions and possesses group of initial cells.
Thus, the correct answer is option D.
Match the wall components with the type of tissues/ tissue system listed. Choose the answer which gives the correct combination of alphabets.
List I
List II
A
Suberin
1
Sclerenchyma
B
Lignin
2
Collenchyma
C
Pectin
3
Epidermis
D
Cutin
4
Phellem
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A- 4, B- 1, C- 2, D- 3
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A- 1, B- 4, C- 2, D- 3
0%
A- 4, B- 2, C- 1, D- 3
0%
A- 4, B- 1, C- 3, D- 2
Explanation
Suberin is found in the phellem layer of the periderm (or cork). It is the outermost layer of the bark. The cells in this layer are dead and abundant in suberin, preventing water loss from the tissues below.
Mature sclerenchyma cells are dead cells that have thickened walls containing lignin. Such cells occur in many different shapes and sizes, but two main types occur- fibres and sclereids.
Collenchyma is strengthened by pectin. So the cell wall is thickened unevenly. The collenchyma cell wall is composed of a primary wall made up of cellulose and at certain places, it is deposited within a secondary wall made up of hemicellulose or pectin.
In some higher plants, the cuticle is a water-impervious protective layer covering the epidermal cells of leaves and other parts and limiting water loss. It consists of cutin, a waxy, water-repellent substance allied to suberin, which is found in the cell walls of cork tissue.
So, the correct answer is option A.
Fascicular or vascular cambium of dicots is
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Intercalary meristem
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Lateral meristem
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Apical meristem
0%
Secretory tissue
Explanation
The vascular bundles in dicotyledons are made up of various tissues of which the xylem and the phloem are the conducting tissues. Between these two is present an important layer of cells which are meristematic - the cambium. Since it lies between the vascular bundle it is called as fascicular cambium. These cambial strips are placed laterally with respect to the circumference of the stem.
Thus, the correct answer is option B.
Dead cells that mainly have a mechanical function are
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Sclerenchyma cells
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Companion cells.
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Wood parenchyma cells
0%
Collenchyma cells
Explanation
Sclerenchyma is a complex tissue which mainly acts as protective and supportive tissue. These are dead tissues.
Fibres are greatly elongated cells whose long, tapering ends interlock, thus providing maximum support to a plant. They can be found almost anywhere in the plant body, including the stem, the roots, and the vascular bundles in leaves.
Sclereids are extremely variable in shape and are present in various tissues of the plant such as the periderm, cortex, pith, xylem, and phloem. They also occur in leaves and fruits and constitute the hard shell of nuts and the outer hard coat of many seeds.
Companion cells are specialized parenchyma cells located in the phloem of flowering plants and closely associated with
the development and function with a sieve-tube element.
Parenchyma is typically composed of living cells that are thin-walled, unspecialized in structure and therefore adaptable, with differentiation, to various functions.
Collenchyma cells have thin primary walls with some areas of secondary thickening. Collenchyma provides extra structural support, particularly in regions of new growth. They are living cells.
Thus, option A is correct.
Wood of Gymnosperms is composed of
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Only tracheids in the xylem
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Only vessels and xylem parenchyma
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Only fibres and xylem parenchyma
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Only fibres and vessels
Explanation
The tracheids, long cells, that conduct water primarily through openings in their side walls are an integral part of gymnosperms. Most gymnosperms possess only tracheids in their xylem.
So, the correct answer is option A.
Scindapsus officinalis
of family Araceae is a unique plant as
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It is epiphytic only in embryonic stages.
0%
It is saprophytic in embryonic stages.
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It is epiphytic only in adult stages.
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It is an insectivorous plant.
Explanation
An epiphyte is a plant that grows non-parasitically upon another plant and derives its moisture and nutrients from the air, rain and debris around it rather than the structure it is attached to.
Scindapsus officinalis
of family
Araceae
is an epiphytic climber clinging by its
adventitious aerial roots. The plant possesses antioxidant activity. The uniqueness of this family is it is epiphytic in the adult stage.
Thus, the correct answer is option C.
Simplest type of stele is
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Solenostele
0%
Siphonostele
0%
Protostele
0%
Dictyostele
Explanation
The earliest vascular plants had stems with a central core of vascular tissue. This consisted of a cylindrical strand of xylem, surrounded by a region of phloem. Around the vascular tissue, there might have been an endodermis that regulated the flow of water into and out of the vascular system. Such, an arrangement is termed as a protostele which is the most primitive and simplest type of stele.
Thus, the correct answer is option C.
The correct evolutionary sequence is
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Tracheids $$\rightarrow$$ fibre tracheids $$\rightarrow$$ libriform fibres
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Fibre tracheids $$\rightarrow$$ tracheids $$\rightarrow$$ libriform fibres
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Libriform fibres $$\rightarrow$$ tracheids $$\rightarrow$$ fibre tracheids
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Tracheids $$\rightarrow$$ libriform fibres $$\rightarrow$$ fibre tracheids
Explanation
As per Bailey (1953) the tracheary elements developed during the evolution of land plants with the need for rapid movement of water and inorganic minerals to the increasing distances of the pant axis. While in lower vascular plants it provided conduction an support, the evolution of higher plants led to the evolutionary sequence of the tracheids to fibre tracheids to libiform fibres.
One of them is absent in closed vascular bundles.
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Cambium
0%
Pith
0%
Ground tissue
0%
All of the above
Explanation
Closed vascular bundles have no cambium in between xylem and phloem.
They lack cambium hence, unable to grow laterally.
Interfascicular cambium is absent in closed vascular bundle. There is direct contact between phloem and xylem. Secondary xylem and phloem are not formed. This is seen in leaves and monocot stems.
They are present in monocot stems.
Thus, the correct answer is option A.
In monocots, the hypodermis is
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Collenchymatous
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Parenchymatous
0%
Sclerenchymatous
0%
Both A and B
Explanation
Hypodermis is present in both dicot and monocot stems. In case of dicots, the hypodermis is made up of collenchyma cells whereas in monocots, it is made up of sclerenchyma cells.
Therefore, the correct answer is option C.
Which of the following meristem is derived from the promeristem?
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Primary
0%
Secondary
0%
Apical
0%
Both (A) and (C)
Explanation
The undifferentiated immature cells with the capacity to divide are called as meristems or meristematic cells. The meristems which chiefly found in clusters are grouped according to origin, position, angle of the cell division plane. Based on its origin, the meristems are further classified as pro-meristems, primary meristems and secondary meristems. Since, the continuously dividing cells of the shoot and root tip is made up of pro-meristems, both the primary meristems and the apical meristems are derived from pro-meristems.
Thus, the correct option is D.
Which of the following statements is/are true?
(a) Uneven thickening of cell wall is characteristic of sclerenchyma.
(b) Periblem forms the cortex of the stem and the root.
(c) Tracheids are the chief water transporting elements in gymnosperms.
(d) Companion cell is devoid of nucleus at maturity.
(e) The commercial cork is obtained from Quercus suber.
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(a) and (d) only
0%
(b) and (e) only
0%
(c) and (d) only
0%
(a), (b) and (c) only
0%
(b), (c) and (e) only
Explanation
Uneven thickening of the cell wall is characteristic of collenchyma. Sclerenchyma has the even thickening on the cell wall made up of lignin.
Periblem forms the cortex of the stem and the root.
Tracheids are the chief water transporting elements in gymnosperms. Vessels are absent in gymnosperms.
Companion cells possess nucleus at maturity.
The commercial cork is obtained from
Quercus suber
.
So, the correct answer is '
(b), (c) and (e) only'.
The lacuna in the vascular bundles of monocot stem is
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Metaxylem
0%
Mucilage canal
0%
Large sized vessel
0%
Lysigenous cavity
Explanation
The first xylem formed is called as protoxylem. The protoxylem vessels have thick, lignified secondary wall which is arranged in annular rings or in spiral form. They are enable of stretching. But later primary and secondary walls of protoxylem are torn to form an internodal cavity called as lacuna. This is a type of lysigenous cavity as the entire cell is dissolved. Water is stored in this lysigenous cavity. Therefore, option D is correct.
Match the two lists and choose the correct option.
List I (vascular bundle types)
List II (Plants)
A
Collateral and open
1
Cucurbita
stem
B
Radial
2
Ferns
C
Bicollateral
3
Maize root
D
Concentric
4
Sunflower
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A- 4, B- 3, C- 1, D- 2
0%
A- 3, B- 4, C- 1, D- 2
0%
A- 4, B- 3, C- 2, D- 1
0%
A- 4, B- 1, C- 3, D- 2
Explanation
Collateral bundles are vascular bundles in which the phloem and xylem lie on the same radius, with the phloem located toward the periphery of the stem and the xylem toward the center. Collateral open vascular bundles are present in dicots, like sunflower.
Bicollateral vascular bundles have 2 patches of cambrium and one patch of xylem at the middle. This type of vascular bundles are found in plants of the family
Cucurbitaceae
and
Solanaceae
.
Concentric vascular bundles have one vascular element surrounding the other on all sides. These are mostly observed in ferns. These are of two types - leptocentric (
Dracena
and
Yucca
) and hydrocentric (
Hydrilla
).
Radial vascular bundle is observed in both dicot and monocot roots. Example- maize roots.
In a transverse section of a dicot root
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The protoxylem vessels are present towards the periphery and metaxylem vessels are present towards the centre.
0%
The protoxylem vessels are present towards the centre and the metaxylem vessels are present towards the periphery.
0%
Both protoxylem and metaxylem vessels are present towards the centre.
0%
Both protoxylem and metaxylem vessels are present towards the periphery.
Explanation
In dicotyledonous plants the root the xylem is exarch i.e. protoxylem is away from the center and metaxylem is towards the center.
Therefore, the correct answer is option A.
In a dicot stem, pericycle gives rise to
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0%
Interfascicular cambium
0%
Phellogen
0%
Secondary cortex
0%
Secondary wood
Explanation
In dicot stem, the secondary vascular tissues originate as a result of the cambial activity.
The cambial cells divide tangentially again and again and produce secondary tissues.
Some of the cells of single-layered pericycle become meristematic, which divides and form a few layers of cells, phellogen.
Hence, In a dicot stem, pericycle gives rise to Phellogen.
So, the correct answer is 'Phellogen'.
The intraxylary phloem is found in
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0%
Salvia
0%
Cucurbita
stem
0%
Calotropis
stem
0%
None of the above
Explanation
The intraxylary phloem is situated on the inner side of the vascular bundles. It is located on the periphery of the pith. It is present either in the form of ring or in isolated patches. It forms from the activity of provascular tissues hence, primary in character.
Salvia
does not show presence of intraxylary phloem.
Cucurbita
stem shows bicollateral vascular bundles which produce outer and inner phloem but intraxylary phloem is absent.
Calotropis
stem shows intraxylary phloem in isolated patches on inner side of vascular bundles.
Therefore, the correct answer is option C.
Choose the correct combination of labelling of hydathode.
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A - guard cells, B - epithem, C - mesophyll, D - epidermis, E - vasculature
0%
A - guard cells, B - epidermis, C - mesophyll, D - epithem, E - vasculature
0%
A - waler pore, B - epidernlis, C - mcsophyll, D - epithem, E - vasculature
0%
A - ostiole, B - epidernlis, C - mesophyll, D - cpithem, E - vasculature
0%
A - water pore, B -hypodermis, C - mesophyll, D - epithem, E - vasculature
Explanation
A hydathode is a secretory tissue found in the leaves of Angiosperms. These secretes the excess water through the pores of the epidermis or margin of the leaves and are present typically at the tip of marginal tooth of the leaves. Mainly found in aquatic plants and in some herbaceous plants that grows in moist places and are commonly seen in water lettuce, water hyacinth, rose, balsam etc. Made of a group of living cells with numerous intercellular spaces filled with water, hydathodes have few or no chloroplasts which represent modified bundle-ends called as epithem cells.
Therefore, the correct answer is option C.
Conjoint and closed vascular bundles with no phloem parenchyma may be observed in
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0%
Monocot stem
0%
Monocot root
0%
Dicot stem
0%
Dicot root
Explanation
Conjoint and closed vascular bundles with no phloem parenchyma may be observed in monocot stem. Open vascular bundles have cambium and the possibility of further xylem and phloem. There is no cambium in closed vascular bundles.
Thus, the correct answer is option A.
Monocot stem are characterized by
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Conjoint, collateral and open vascular bundle
0%
Conjoint, collateral and closed vascular bundle
0%
Radial
0%
Both A and C
Explanation
Anatomy of the monocot stem shows that while the vascular bundles are oval in shape, numerous, and scattered, it is by nature, conjoint, collateral, closed, and endarch without any lysigenous activity.
In conjoint vascular bundle xylem and phloem are situated at the same radius.
In collateral vascular bundle is a vascular bundle in which a phloem strand is present outside the xylem strand, on the same radius side by side.
In closed vascular bundle means that there is an absence of a cambium. They are not capable of forming the secondary xylem and phloem tissues.
Therefore, the correct answer is option B.
Actinostele is the modification of
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Protostele
0%
Siphonostele
0%
Solenostele
0%
Dictyostele
Explanation
The earliest vascular plants had stems with a central core of vascular tissue. This consisted of a cylindrical strand of xylem, surrounded by a region of phloem. Around the vascular tissue, there might have been an endodermis that regulated the flow of water into and out of the vascular system. Such, an arrangement is termed a protostele, which is the simplest type of stele. Actinostele is a variation of the protostele in which the core is lobed or fluted. This stele is found in many species of club moss. Actinosteles are typically exarch and consist of several to many patches of protoxylem at the tips of the lobes of the metaxylem. Exarch protosteles are a defining characteristic of the lycophyte lineage.
Thus, the correct answer is option A.
Longest cells in plant kingdom with sclerenchyma fibres 55 cm long belong to
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Linum usitatissimum
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Figs
0%
Musa textilis
0%
Boehmeria nivea
Explanation
Sclerenchyma cell is a thick walled, dead, lignified cell, which performs a mechanical function. The longest plant cell is the sclerenchyma cell of
Boehmeria nivea
(ramie; about 55 cm in length).
Sclerenchyma fibres of
Linum usitatissimum
and ramie (
Boehmeria nivea
) have cellulosic cell wall and thus are extremely soft and elastic and well suited for the processing into textiles.
Musa textilis
has hard fibres due to presence of high proportion of lignin in cell wall.
Figs have sclereids in their fruits, which impart hardness and strength.
Thus the correct answer is option D.
Which of the following is the correct match?
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A- Fusiform initials, B- Ray initials, C- Non-storied cambium, D- Storied cambium
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A- Fusiform initials, B- Non-storied cambium, C- Ray initials, D- Storied cambium
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A- Fusiform initials, B- Non-storied cambium, C- Storied cambium, D- Ray initials
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A- Non-storied cambium, B- Fusiform initials, C- Storied cambium, D- Ray initials
Explanation
The given diagrams are of longitudinal view of cambium. Cambium is made of two types of cells, fusiform initials and ray initials. Fusiform initials are spindle shaped, elongated cells with tapering ends. These cells form secondary xylem and secondary phloem.
In this diagram, A is showing fusiform initials.
Ray initials are small, isodiametric cells which are packed in regular groups. These cells form xylem and phloem rays which are arranged in horizontal manner.
In this diagram, B is showing ray initials.
Cambium cells are also classified
in
two types on the basis of their orientation as storied and non-storied. In
storied
type of cambium, the short fusiform cells of all tiers lie at the same level.
In the diagram, C is showing non-storied cambium.
In non-storied type of cambium, the long fusiform cells of different tiers overlap each other.
In the diagram, D is showing non-storied cambium.
Thus, the correct answer is option A.
2 to 6 xylem and phloem patches are present in
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Dicot root
0%
Monocot root
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Root hair
0%
All of the above
Explanation
2-6 xylem and phloem i.e., vascular bundles are present in the dicotyledonous root. Monocot roots have more than 8 vascular bundles.
Hence, option A is correct.
In which of herbaceous dicot, abnormal primary vascular bundles are found in the medullary region?
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0%
Casuarina
0%
Bougainvillea
0%
Boehmaria
0%
Lantana
Explanation
Abnormal secondary growth in dicots do not always follow the of vascular cambium producing xylem in the inside and phloem to the outside. The species of
Bougainvillea
show abnormal growth in the vascular bundles, with a series of cambia rising outside the phloem. This is due to the abnormal origin of the cambium.
Therefore, the correct answer is option B.
Which wood was used by Egyptians in 4000 B.C. for making ships?
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Teak
0%
Cedar
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Sal
0%
Shisham
Explanation
Cedar was very important to the Egyptians. They used it for making boat. These boats were built of relatively short blocks of timber. It was very easy to reach the cities and towns by boat through Nile. It was cheap and quick. The necessary water power was provided by the current and the wind. People traveled through Nile with stone for projects or grain for the kings stores and merchants carried wares for sale. It was believed to be first used about 4000 B.C. and became Egypt's major exports.
Thus, the correct answer is option B.
Sclerenchymatous bundle sheath is present in
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Dicots.
0%
Sunflower.
0%
Monocots.
0%
Beans.
Explanation
Sclerenchymatous bundle sheath is present in monocots. Each vascular bundle is surrounded by a bundle sheath composed of a single layer of compactly arranged barrel-shaped cells. The bundle sheath encloses both phloem and xylem.
Therefore, the correct answer is option C.
Monocot roots differ from dicot roots in having
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Open vascular system
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Presence of root hair
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Number of xylem / phloem strands
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Presence of cortex
Explanation
Most of the features of the dicot and monocot roots are similar except the vascular bundles. In the dicot root, there are 2-6 bundles of xylem and phloem alternating whereas in monocots the number of xylem and phloem strands are more than 8. Further, the xylem vessels in dicots are polygonal and those of monocots are oval.
Therefore, the correct answer is option C.
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Practice Class 11 Medical Biology Quiz Questions and Answers
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