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CBSE Questions for Class 11 Medical Biology Anatomy Of Flowering Plants Quiz 6 - MCQExams.com
CBSE
Class 11 Medical Biology
Anatomy Of Flowering Plants
Quiz 6
Meristematic tissue occurs in
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Stems
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Roots
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All growing tips
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Both of the (A) and (B)
Explanation
Meristem is the region marked by the presence of active cell growth and the tissues present in meristem are termed as meristematic tissues.
On the basis of their position in the plant body, meristems are grouped as apical, lateral or intercalary meristem.
Stem has apical meristem in the shoot apex, intercalary meristem in nodes and lateral meristem in form of cambium in vascular bundles.
Roots have apical meristem root apex and lateral meristem in form of cambium in vascular bundles. Shoot and root tips are the growing tips of a plant. Due to presence of root cap in terminal position, root apical meristem is subterminal in position thus, not all the growing tips have meristem.
Therefore, the correct answer is option D.
Cork cambium represents
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Secondary meristem
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Primary meristem
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Intercalary meristem
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Apical meristem
Explanation
Cork cambium is a tissue found in many vascular plants as part of the periderm. The cork cambium is a lateral meristem and is responsible for secondary growth that replaces the epidermis in roots and stems. It is found in woody and many herbaceous dicots , gymnosperms and some monocots, which usually lack secondary growth.
Monocot root differs from dicot root in having
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Open vascular bundle
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Scattered vascular bundle
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Large pith
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No pit
Explanation
Pith is the innermost region of the root representing the central axis. It is composed of few loosely arranged parenchyma cells. Large pith is present in monocot roots. In dicot roots, pith is absent. Open vascular bundles are present in dicots. Scattered vascular bundles are present in moncot stem. Radial vascular bundles are present in both monocot and dicot roots.
Thus, the correct answer is option C.
Active divisions occur in the cells of
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Xylem
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Phloem
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Cambium
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Collenchyma
Explanation
Secondary growth refers to the growth that results from cell division in the cambia or lateral meristems and that causes the stems and roots to thicken, while primary growth is growth that occurs as a result of cell division at the tips of stems and roots, causing them to elongate and gives rise to primary tissue.
In many vascular plants, secondary growth is the result of the activity of the two lateral meristems, the cork cambium and vascular cambium. Arising from lateral meristems, secondary growth increases the girth of the plant root or stem, rather than its length. As long as the lateral meristems continue to produce new cells, the stem or root will continue to grow in diameter.
In woody plants, this process produces wood, and shapes the plant into a tree with a thickened trunk. So, active divisions occurs in cambium. Active divisions will not occurs in xylem, phloem and collenchyma.
Thus, the correct answer is option C.
In a woody dicotyledonous tree, which of the following parts will mainly consist of primary tissues?
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Only stem and root
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Only roots
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Only shoot tips
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Flowers, fruits and leaves
Explanation
Meristem is the region marked by presence of active cell growth and the tissues present in meristem are termed as meristematic tissues. On the basis of their position in plant body, meristems are grouped as apical, lateral or intercalary meristem. Secondary growth is caused by lateral meristem.
A flower is defined as condensed shoot and is derived from shoot apical meristem by the process of specialization of leaves into floral appendages.
Leaf is green, exogenous, lateral outgrowth which develops from shoot apical meristem.
Fruit is a ripened ovary which serves to protect the ripening ovule.
Thus, flower, leaf and ovary develop from primary meristem and lack any lateral meristem that causes secondary growth, i.e., these structures mainly have primary tissues.
Stem and roots have inter- and intra-fascicular cambium which is a lateral meristem (secondary) and produce secondary stelar (secondary xylem and phloem) and extra stelar tissues (phelloderm, phellogen and phellem). Shoot and root tip have apical meristem.
Thus, the correct answer is option D.
Periblem form
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Endodermis
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Cortex
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Both of (A) and (B)
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Epidermis
Explanation
Histogen theory was proposed by Hanstein in 1870. According to this theory, shoot apical meristem consists three distinct zones namely, dermatogen (external layer) which form outer covering of all organ of plant. Periblem (middle layer) which gives rise to cortex and endodermis. Plerome (central layer) which forms pith and primary vascular bundle.
Thus, the correct answer is option C.
Vascular cambium forms
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Secondary xylem and secondary phloem
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Primary xylem and primary phloem
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Only secondary phloem
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Only primary xylem
Explanation
The vascular cambium is located between the xylem and the phloem in the stem and root of a vascular plant, and is the source of both the secondary xylem growth (inwards, towards the pith) and the secondary phloem growth (outwards). It is a cylinder of unspecialized meristem cells that divide to give new cells, which then specialize to form secondary vascular tissues. Vascular cambium are found in dicots and gymnosperms but not monocots, which usually lack secondary growth
So, the correct answer is '
Secondary xylem and secondary phloem'
Periderm includes
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Phellem
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Phelloderm
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Phellogen
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All of the above
Explanation
The periderm is the secondary protective dermal tissue that replaces the epidermis during growth in thickness of stems and roots of gymnosperms and dicotyledons (i.e., secondary growth). Unlike typical epidermis, the periderm is a multilayered tissue system, the bulk of which usually constitutes the cork or phellem, phellogen or cork cambium and phelloderm.
Thus, the correct answer is option D.
Root apex has a zone of slowly dividing cells in the middle of rapidly dividing cells. It is known as
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Quiescent centre
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Sluggish centre
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Dormant centre
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Non meristematic zone
Explanation
The quiescent centre is a small group of cells with low mitotic activity (no cell division), which is found in the root meristem at the root apex and is surrounded by groups of dividing cells.
Hence the correct option is A.
Passage cells are thin-walled cells found in
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Central region of style through which the pollen tube grows towards the ovary
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Endodermis of roots facilitating rapid transport of water from cortex to pericycle
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Phloem elements that serve as entry points for substances for transport to other plants parts
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Testa of seeds to enable emergence of growing embryonic axis during seed germination
Explanation
Passage cells are endodermal cells of older roots, which have retained thin walls and Casparian strips rather than becoming suberized and waterproof like the other cells around them, to continue to allow some symplastic flow to the inside. Passage cells function to allow transfer of solutes, such as calcium and magnesium into the stele, in order to eventually reach the transpiration system.
Cells taking part in conduction of sap are
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Sieve tubes
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Trachea
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Sieve cells
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Stone cells
Explanation
Xylem tracheae are the integral component of xylem. These are also known as xylem vessels. They are generally present in higher angiosperms and these are involved in conduction. The tracheae are found arranged parallel to each other, extending from one end of the plant body to another. The tracheae are long cylindrical dead cells. They are characterized by a thick cell wall consisting of a primary wall and a secondary wall. The primary wall is made up of cellulose, whereas the secondary wall is made up of lignin. There is a spacious lumen that extends throughout the length of the trachea. The deposition of lignin in the secondary wall is not always uniform. As a result, the xylem vessels exhibit different types of secondary thickenings. Xylem vessels have perforation plates at their end walls, which are absent in other xylem elements. Thus, option B is correct.
In a dicotyledonous stem, the sequence of tissues from the outside to the inside is
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Phellem, Pericycle, Endodermis, Phloem
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Phellem, Phloem, Endodermis, Pericycle
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Phellem, Endodermis, Pericycle, Phloem
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Pericyle, Phellem, Endodermis, Phloem
Explanation
Phellem is outermost layer of cork cambium, which is suberised. Hence, this is the first layer to be found.
Endodermis is one the layer of cortex, which is to be found under the phellem.
Pericycle is the layer present between endodermis and vascular bundles.
Dicotyledonous stem possess conjoint, collateral vascular bundle, where xylem is internal and phloem is external. Therefore, phloem is to be encountered after the pericycle.
The waxy substance associated with the walls of cork or the walls of cork cells are mostly impregnated with
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Cutin
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Suberin
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Lignin
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Hemicellulose
The lateral branches of roots (dicot) generally originates from
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Cortex
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Endodermis
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Cork cambium
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Pericycle cells lying against protoxylem
Explanation
The pericycle is a cylinder of parenchyma or sclerenchyma cells that lies just inside the endodermis and is the outer most part of the stele of plants. Although, it is composed of non-vascular parenchyma cells, it is still considered part of the vascular cylinder, because it arises from the procambium as do the vascular tissues it surrounds. In eudicots, it also has the capacity to produce lateral roots. Branch roots arise from this primary meristem tissue. In plants undergoing secondary growth, the pericycle contributes to the vascular cambium often diverging into a cork cambium.
A bundle with xylem and phloem separated by a strip of cambium is
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Collateral and closed
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Collateral and open
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Concentric and closed
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Bicollateral and open
Explanation
A vascular bundle 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 centre is called as collateral.
On the basis of presence or absence of cambium, collateral bundles are grouped as open or close bundles. Those with cambium are termed as open vascular bundles, while the vascular bundles without cambium are termed as closed.
So, the correct answer is option B.
Which of the following tissues is comprised of dead cells?
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Parenchyma
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Collenchyma
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Sclerenchyma
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All of the above
Explanation
Parenchyma, collenchyma, and sclerenchyma are the three types of simple permanent tissues in plants. Parenchyma and collenchyma are comprised of living cells. Sclerenchyma is made up of dead cells. The cells of this tissue have the presence of lignin in their cell walls. This makes the cells hard and stiff.
This tissue is present in stems,
around vascular bundles, in the veins of leaves,
and in the hard covering of seeds and nuts. It
provides strength to the plant parts.
So, the correct answer is option C.
Hard, lignified, thick-walled, long and pointed cells constitute
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Parenchyma
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Collenchyma
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Sclereids
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Sclerenchyma
Explanation
Sclerenchyma cells have thick lignified secondary walls and often die when mature. It provides the main structural support to a plant.
They are long and pointed cells.
Parenchyma cells have thin primary walls and usually remain alive after they become mature. It forms the filler tissue in the soft parts of plants.
Collenchyma cells have thin primary walls with some areas of secondary thickening. Collenchyma provides extra structural support, particularly in regions of new growth.
Sclereids are a reduced form of sclerenchyma cells with highly thickened, lignified cellular walls that form small bundles of durable layers of tissue in most plants. Sclereids are relatively short.
Hence the correct option is D.
Grafting is not possible in monocots because they
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Lack cambium
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Have scattered vascular bundles
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Have parallel venation
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Are herbaceous
Explanation
Monocot plants cannot be grafted as they lack the cambium tissue which is present in dicot plants. Cambium tissue is a meristematic tissue which is present in the vascular bundles of the dicot plants. This tissue has a regeneration capacity due to which it can form new tissue at the time of grafting. The lack of cambium in monocots makes it impossible to graft. It only works with dicots and gymnosperms and not with monocots. So, grafting is not possible in monocots because they lack cambium and not because scattered vascular bundles, parallel venation and herbaceous.
Thus, correct answer is option A.
A group of cells similar in form, function and origin is
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Organ
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Organelle
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Tissue
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Organoid
In dicot root showing secondary growth, cork is found
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External to primary cortex
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Inner to epidermis and outer to pericycle
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Outer to endodermis and inner to primary cortex
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Inner to endodermis and external to primary phloem
Explanation
During secondary growth, rupturing of epidermal cell and outer cortex by secondary tissues induces formation of new protective layer, periderm turning the single layered pericycle into multi layered meristem that divides to form cork cambium or phellogen. The cork cambium exhibit meristematic activity and produces cork or phellem towards the periphery and phelloderm on inside, i.e., extrastellar growth. Moving from centre to periphery, a dicot root has pith, secondary xylem, secondary phloem, phelloderm (secondary cortex), phellogen (cork cambium), cork (phellem) and bark. Since, primary cortex is ruptured and is not present in secondary root. Cork is extra stellar tissues which is present outside the stele (vascular bundle, pith and medullary rays surrounded by pericycle) region and hence, cannot be present inner to endodermis.
Thus, the correct answer is option B.
Exarch and polyarch xylem strands are found in
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Monocot stem
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Dicot stem
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Monocot root
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Dicot root
Explanation
In monocot root vascular bundles are radial in arrangement. There are eight bundles each of xylem and phloem. Hence, the condition is described as polyarch. Xylem is described as exarch in monocot root.
In maize, ............. roots are present other than the normal roots.
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Stilt roots
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Tuberous roots
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Prop roots
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Nodulated roots
What are the characteristics of permanent tissue?
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They originate from meristematic tissue.
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Cells of these tissues have no power of division.
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Cell wall is comparatively thick.
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All of the above
Which of the following is correct sequence of layers in typically monocot root (from outer surface to inside)?
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Pericyle, cortex, endodermis, epiblema
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Epiblema, endodermis, cortex, pericycle
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Epiblema, cortex, endodermis, pericycle
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Epiblema, pericycle, cortex, endodermis
Explanation
The outer most layer of monocot root is rhizodermis or epiblema which has compactly arranged tubular cells and unicellular root hair as their extension. Just beneath the epiblema are multiple layers of parenchymatous cells with ample intercellular space, it is cortex. The inner most layer of cortex forms endodermis which has compactly arranged barrel shaped cells with casparian strips at their anticlinal wall. The uniseriate layer of thin walled parenchymatous cells, present below endodermis, which are sclerified in old roots makes pericycle. The vascular bundles are present as alternating strands of xylem and phloem, the discrete xylem strands alternated with phloem strands. The central parenchymatous cells form pith.
Therefore, the correct answer is option C.
Pith and cortex belongs to
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Epidermis
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Ground tissue
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Vascular tissue
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Bundle sheath
Explanation
Epidermis is the part of epidermal tissue system and forms the outer protective covering of primary plant body.
All tissues of a plant body except epidermal and vascular tissues system makes ground tissue, which can be intrastelar and extrastelar tissue, depending on its position with respect to stele.
Cortex and endodermis constitute extra stelar ground tissue, while pericycle, pith and medullary ray constitute the intra stelar ground tissue.
Vascular tissues system comprise of xylem, phloem and cambium. Thus, the correct answer is option B.
The cambium which produces cork is called as
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Phelloderm
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Phellogen
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Periblem
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Plerome
Explanation
Cork cambium or phellogen is a tissue found in many vascular plants as part of the periderm.
The cork cambium is a lateral meristem and is responsible for secondary growth that replaces the epidermis in roots and stems. It is found in woody and many herbaceous dicots, gymnosperms and some monocots, which usually lack secondary growth.
Cork cambium is one of the plant's meristems the series of tissues consisting of embryonic cells from which the plant grows. It is one of the many layers of bark, between the cork and primary phloem. The function of cork cambium is to produce the cork, a tough protective material. Thus, option B is correct.
Vascular bundles occur in a ring in
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Monocot stem
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Leaf
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Root
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Dicot stem
Explanation
In the dicot stem, the vascular bundles are arranged in a ring, with pith concentrated at the core of the stem, rather than being scattered throughout the plant interior. In dicot stem wedgw shaped, definite and arranged in one or two rings. Vascular bundles are conjoint, collateral and open.
Sclereids or stone cells are modified form of
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Collenchyma
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Sclerenchyma
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Fibers
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Xylem vessels
Explanation
Sclereids or stone cells are a reduced form of sclerenchyma cells. It has highly thickened, lignified cellular walls that form small bundles of durable layers of tissue in most plants. They are a type of sclerenchyma cells that differs from the fibre cell by not being greatly elongated. It often occurs singly (an idioblast) or in small groups, giving rise to a gritty texture in, for instance, the pear fruit, where it is known as a stone cell. It may also occur in layers, for example in hard seed coats. A type of cell with thick cell walls, consisting of lignin, that is commonly found on the outer 'skin' of fruits. So, sclereids or stone cells are modified sclerenchyma.
So, the correct answer is option B.
Passage cells are found in
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Monocot root
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Monocot stem
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Aerial root
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Dicot stem
Explanation
Passage cells are endodermal cells of older roots which have retained thin walls and Casparian strips rather than becoming suberized and waterproof like the other cells around them, to continue to allow some symplastic flow to the inside. Passage cells function to allow transfer of solutes, such as calcium and magnesium into the stele, in order to eventually reach the transpiration system.
Which of the following does not contain pith?
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Siphonostele
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Protostele
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Eustele
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None of the above
Explanation
Protostele is the most primitive type of stele with central xylem surrounded by phloem and pericycle. Pith is absent in them.
Medullation (appearance of pith) of a protostele with central pith is called as siphonostele and thus has central pith surrounded by xylem, phloem and pericycle.
Separation of vascular strands by parenchyma in siphonostele give rise to eustele. Thus, the correct answer is option B.
Primary growth is caused by
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Apical meristem
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Lateral meristem
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Dermatogen
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Plerome
Explanation
All plant growth occurs by cell division and cell elongation. Cell division occurs primarily in regions of undifferentiated cells, known as meristems. Cell division in the apical meristems and subsequent elongation and maturation of the new cells produces primary growth.
An apical meristem is a region of high cell division that contributes to the extension of the plant.
Vessels and companion cells are characteristics of
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Angiosperms
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Gymnosperms
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Pteridophytes
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Ferns
Endodermis mainly
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Acts as a water tight jacket
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Provides protection
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Maintains rigidity
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Help in transpiration
Explanation
The endodermis is the central, innermost layer of cortex in some land plants. It is made of compact living cells surrounded by an outer ring of endodermal cells that are impregnated with hydrophobic substances (Casparian Strip) to restrict apoplastic flow of water to the inside. The endodermis is the boundary between the cortex and the stele. In many seedless vascular plants, the endodermis is a distinctly visible layer of cells immediately outside the vascular cylinder (stele) in roots and shoots. In most seed plants, especially woody types, an endodermis is absent from the stems but is present in roots.
The endodermis helps regulate the movement of water, ions and hormones into and out of the vascular system. It may also store starch, be involved in perception of gravity and protect the plant against toxins moving into the vascular system. Thus, option A is correct.
In monocots, .............. root system is observed.
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Tap root
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Fibrous root,
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Both A and B
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None of the above
Polyarch condition is found in
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Monocot root
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Dicot root
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Monocot stem
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Dicot stem
Explanation
A. Monocot root
Reason: In monocot roots, vascular bundles are present in radial arrangement. There are eight bundles in each of xylem and phloem. Therefore, the condition is denoted as polyarch. Xylem is denoted as exarch in monocot root.
Parenchyma tissues are found in _______ part of the plant body.
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All
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Leaves
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Stem
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Roots
Select the statement which correctly describes tissues.
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Group of cells with common origin but dissimilar functions.
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Group of cells with common origin and similar structure.
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Group of cells which perform similar function.
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Group of cells with common origin, similar structure and similar function.
Meristems are
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Permanent cells
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Dividing cells
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Mechanical cells
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None of the above
Explanation
A meristem is the tissue in most plants containing undifferentiated cells, found in zones of the plant, where growth can take place. Meristematic cells give rise to various organs of the plant and keep the plant growing. The shoot apical meristem gives rise to organs like the leaves and flowers, while the root apical meristem provides the meristematic cells for the future root growth.
So, meristems are dividing cells and not permanent cells as, they differentiate to give various organs
So, the correct answer is '
Dividing cells'
Periblem gives rise to
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Epidermis
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Cortex
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Cortex and endodermis
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Endodermis
Explanation
In the histogen theory Henstein divided the shoot apex into various zones. Each zone consists of a group of initial cells and called as histogen or a tissue builder.
The major histogens of the stem and roots are -(a) the dermatogen, a meristematic external layer, (b) the plerome, a central core and (c) the periblem, the region between the two.
The dermatogen gives rise to the epidermis, the prerome to the primary vascular bundles and the periblem develops into the cortex and endodermis.
Which is not true for dicot root _____________.
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Less developed pith or absent
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Secondary growth
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Both
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$$15-20$$ vascular bundles
Explanation
In dicot root vascular bundles are 2 to 6 in number and radial.
Hence, the answer that is not true for dicot is presence of 15-20 vascular bundles.
So, the correct answer is '15-20 vascular bundles'
Gaseous exchange between air and internal tissues of old corky stem takes place through
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Sieve plates
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Pits
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Stomata
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Lenticels
Explanation
Lenticel is a pore in the stem of a woody plant, showing a raised spot that may be filled with a powdery substance. The pore permits air to reach tissue below the surface. Stomata are present in leaves, Sieve plates are present in phloem tissue for the transport of carbohydrates and
Pits
are the characteristic depressions on the cell walls for the transport of water and minerals.
Which one of the following plant tissue lacks protoplasm at maturity?
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Sclerenchyma
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Collenchyama
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Parenchyma
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Epidermis
Explanation
Collenchyma contains living, elongated cells with proto
plasm at maturity.
Parenchyma cells are thin-walled, flexible and loosely packed cells. They are alive at maturity and contain protoplasm.
Sclerenchyma cells are dead, long, thin, narrow with thickened walls without any internal space. They do not possess any protoplasm at maturity.
Hence, option A is correct.
Plant length is increased by the activity of ________________.
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Apical meristem
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Lateral meristem
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Cambium
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All of the above
Explanation
Lateral meristems are vascular cambium and cork combium. They are responsible for secondary growth of plant. They increase plant diameter. Cambium are of two types as vascular cambium and cork cambium. Cambium possess meristematic cells which are involved in secondary growth. They increase plant diameter.
Apical meristem are present at the tip of root and shoot. Cells of apical meristem divide and give rise to new cells. This process increase the length of root and shoot.
The main function of sclerenchyma is ___________________.
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Conduction of food
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Synthesis of food
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Exchange of gases
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Mechanical support
Explanation
Conduction of food from leaves to other parts of the plant is carried out by phloem cells.
The synthesis of food is carried out by chlorenchyma cells. These are parenchyma cells with chlorophyll pigments.
Exchange of gasses is carried out by stomata, which are small pores present on leaf epidermis.
Sclerenchyma is a type of permanent tissue. They are dead, long, thin narrow cells with thickened walls without any internal space. This tissue makes the plant hard and stiff. They provide mechanical support to plants.
So, the correct answer is option D.
Plant length is increased by_____________
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Lateral meristem
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Apical meristem
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Primary meristem
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Secondary meristem
Explanation
Apical meristem is a meristem at the tip of a plant shoot or root that produces auxin and causes the shoot or root to increase in length.
Growth that originates in the apical meristem is called primary growth. lateral, primary and secondary meristem does not cause an increase of plant length.
Therefore, the correct answer is option B.
Conduction of water and inorganic solutes.
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Xylem
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Phloem
0%
Tracheid
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Vessles
A group of cells having a common origin and performing similar function is called as
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Tissue
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Organ
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Organ system
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Cell aggregate
Explanation
Organ is a collection of tissues combined in a structural unit to perform a common function.
Organ system is a unit in which many organs work together to carry out one particular function. For example- cardiac cycle is carried out by heart, blood vessels and blood.
Cell aggregate is an aggregation of cells at a particular site in a particular situation, e.g. when blood vessels being ruptured then platelets become aggregated at that site.
A group of cells having a common origin and performing a similar function is called as tissue.
Lignified elongated dead cells are__________________.
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Parenchyma
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Collenchyma
0%
Sclerenchyma
0%
None of these
Explanation
Parenchyma cells are thin-walled, flexible and loosely packed cells. They are living cells.
Their shape changes as per function.
Collenchyma cells are living, elongated and irregularly thickened at corners with less intercellular space.
Sclerenchyma is a type of permanent tissue. They are dead, elongated, thin, narrow cells with thickened walls without any internal space.
Therefore, option C is correct.
Which of the following promotes cell division in vascular cambium?
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Gibberellin
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Cytokinin
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Auxin
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None of these
Explanation
The vascular cambium is located between the xylem and the phloem in the stem and root of the vascular plant and is the source of both the secondary xylem growth and the secondary phloem growth.
Cytokinins are found in sites of active cell division in plants and promote vascular cambium growth.
Thus, the correct answer is option B.
Which of the following is responsible for apical dominance?
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GA$$_{3}$$
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IAA
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ABA
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Florigen
Explanation
Auxin is a general name for a group of hormones that are involved with growth responses. The most important auxin found in plants is indole-3-acetic acid.
Auxins are known to play a role in apical dominance. In most plants, the growing apical tip inhibits the growth of lateral buds. This is known as apical dominance. If the terminal or apical tip of the plant is removed lateral buds will elongate and grow. It is further known that if auxin is applied to the severed shoot tip, the lateral buds will remain suppressed. Thus, the correct answer is option B.
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Practice Class 11 Medical Biology Quiz Questions and Answers
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