MCQ ON SECONDARY GROWTH/VASCULAR CAMBIUM / SECONDARY GROWTH/ VASCULAR CAMBIUM class 11 for NEET | SECONDARY GROWTH VASCULAR CAMBIUM class 11| MCQ ON SECONDARY GROWTH/ VASCULAR CAMBIUM with Answer | Check the below NCERT MCQ question for class 11Biology based on the with Answers.
MCQ on SECONDARY GROWTH/VASCULAR CAMBIUM class 11Biology with answers were prepared based on the latest pattern.We have provided class 11 Biology MCQs question with Answers to help students understand the concept very well.
MCQ ON SECONDARY GROWTH/VASCULAR CAMBIUM is useful for NEET / CSIR / UGC / CBSE / ICSE / AIIMS / EXAM / AFMC EXAM / STATE LEVEL MEDICAL EXAM/ KVS PGT BIOLOGY / NVS PGT BIOLOGY EXAM 2023-2024 ,2025
SECONDARY GROWTH/ VASCULAR CAMBIUM :-
The growth of the roots and stems in length with the help of apical meristem is called the primary growth.
Apart from primary growth most dicotyledonous plants exhibits in increase in the girth. This increase is called a secondary growth.
The tissue involved in the
Secondary growth are the two lateral meristems vascular cambium and cork cambium.
The merismetic layer that is responsible for cutting off vascular tissue xylem and phloem is called vascular cambium.
In the young steam it is present in patches as a single layer between the xylem and phloem .Later it forms a complete ring.
Formation of cambial ring:-
In dicot stems, the cells of cambium present between primary xylem and primary phloem is the intrafascicular cambium.
The cells of medullary rays adjoining these intrafascicular cambium become merismetic and form the interfascicular cambium.
Thus, a continuous ring of cambium is formed.
ACTIVITY OF CAMBIUM RING :-
The cambium ring becomes active and begins cut off new cells, both towards the inner and outer sides.
The cells cut off towards the pith , mature into secondary xylem and the cells cut off towards the periphery mature into secondary phloem.
DICOTYLEDONOUS LEAF AND MONOCOTYLEDONOUS LEAF :-
The vertical section of a dorsoventral leaf through the lamina shows three main parts namely epidermis mesophyll and vascular system.
The epidermis which covers both the upper surface and lower surface of the leaf has a conspicuous cuticle .
The abaxial epidermis generally bears more stomata than the adaxial epidermis.
The latter may even lack stomata .
The tissue between the upper and the lower epidermis is called the mesophyll.
Mesophyll which possess chloroplast which carry out photosynthesis is made up of parenchyma .
It is of two types – the palisade parenchyma and the spongy parenchyma .
The vascular bundles are surrounded by a layer of thick walled bundle sheath cells.
The anatomy of isobilateral leaf is similar to that of the dorsoventral leaf in many ways.
It shows the following characteristic differences.
In an isobilateral leaf the stomata are present on the both the surfaces of the epidermis and the mesophyll is not differentiated into palisade and spongy parenchyma.
In grasses certain adaxial epidermal cells along the veins modify themselves into large empty colourless cells . These are called bulliform cells.
The transverse section of a typical young dicotyledonous stems shows that the epidermis is the outermost protective layer .
Covered with a thin layer of cuticle , it may be trichomes and a few stomata .The cells arranged in multiple layers between epidermis and pericycle constitute the cortex.
It consists of three sub-zones . The outer hypodermis consist of a few layers of collenchymous cells with conspicuous intercellular spaces.
The innermost layer of the cortex is called endodermis.
The cells of the endodermis are rich in starch grains and the layer is also referred to as starch sheath.
Pericycle is present on the inner side of endothermis and above the phloem in the form of semi-lunar patches of sclerenchyma.
In the transverse section of the sunflower root of dicotyledonous root , the internal tissue organisation as follows :-
The outermost layer is epidermis. Many of the epidermal cells protrude in the form of unicellular root hairs.
The cortex consists of several layers of thin – walled parenchymatous cells with intercellular spaces. The innermost layer of a cortex is called endodermis.
It comprises a single layer of barrel – shaped cells without any intercellular spaces.
The tangential as well as radial walls of the endodermal cells have a deposition of water impermeable.
EPIDERMAL TISSUE SYSTEM :-
THE EPIDERMAL TISSUE SYSTEM forms the outermost covering of the whole plant body and comprises epidermal cells stomata and the epidermal appendages the trichomes and hairs.
The epidermis is the outermost layer of the primary plant body. It is made up of elongated compactly arranged cells which form a continuous layer. Epidermis is usually single layered. Epidermal cells are parenchymatous with a small amount of cytoplasm lining the cell
wall and a large vacuole.
The outside of the epidermis is often covered with a thick layer called the cuticle which prevents the loss of water.
Cuticle is absent in roots.
Stomata aur structures present in epidermis of the leaves.
Stomata regulate the process of transpiration and gases exchange. Each stoma composed of two bean shaped cells known as guard cells.
Guard cells possess chloroplast and regulate theopening and closing of stomata.
THE COMPLEX TISSUES ARE MADE OF MORE THAN ONE TYPE OF CELLS.
THIS WORK TOGETHER IS A UNIT.
Xylum and phloem constituent the complex tissues in plants.
. PHLOEM :- PHLOEM transports food materials, usually from leaves to other parts of the plants. Phloem in angiosperm is composed of Sieve tube elements, companian cells, phloem parenchyma, and phloem fibres.
Gymnosperms have albuminous cells and sieve cells .They lacks sieve tubes and companion cells.
Sieve tubes elements are also long tube like structures arranged longitudinally and are sieve – like manner to form the sieve plates.
Companion cells :– The companion cells are specialised parenchymatous cells which are closely associated with sieve tubes elements.
PHLOEM Parenchyma :- It is made up of elongated tapering cylindrical cells which have dense cytoplasm and nucleus.
PHLOEM fibers:- it is made up of sclerenchymatous cells.There are generally absent in the primary phloem but are found in the secondary phloem.
XYLEM FUNCTION is a conducting tissue for water and minerals from roots to the stem and leaves . It also provides mechanical strength to the plants.
It is composed of four different kinds of elements , tracheids, vessels, xylem fibres , xylem parenchyma.
Gymnosperms lacks vessels in their xylem.
Tracheids are elongated or tube like cells with thick and lignified walls and tapering ends.
These are dead and are without protoplasm. The inner layers of cell walls have thickening which vary in form.
Vessel is along cylindrical tube like structure made of many cells called vessels members each with lignified walls and a large central cavity.
Xylem fibers have highly thickened walls and obliterated central lumens.
XYLEM parenchyma cells are living and thin walled and their cell walls are made up of cellulose.
They store food materials in the form of starch or fat .
The cells of the permanent tissues do not generally divide further. Permanent tissue having all cells similar in structure and functions are called simple tissues.
Permanent tissues having many different types of cells are called complex tissues.
Simple tissues:-a simple tissue is made of only one type of cells. The various simple tissues in plants are parenchyma, collenchyma and Sclerenchyma.
Parenchyma forms the major component within organs. The cells of the parenchyma are generally isodiametric.
They may be spherical , oval , round ,polygonal or elongated in shape.
Their walls are thin and made of cellulose.
They may either be closely packed or have small intercellular spaces.
The Parenchyma performs various functions like photosynthesis storage and secretion.
Collenchyma:-the Collenchyma occurs in layers below the epidermis in dicotyledonous plants.
It is found either as a homogeneous layer or patches. It consist of cells which are much thickened at the corners due to deposition of cellulose , hemicellulose and pectin.
Sclerenchyma:- it consist of long narrow cells with thick and lignified cell walls having a few or numerous pits.They are usually dead and without protoplasts.
SECONDARY GROWTH / VASCULAR CAMBIUM class 11 for NEET/KVS PGT BIOLOGY / NVS PGT BIOLOGY EXAM 2023-2024,2025
1. The growth of the roots and stems in length with the help of apical meristem is called the
(a) primary growth
(c) vascular system
(d) secondary growth
Ans (a) primary growth
2. Apart from the primary growth most dicotyledonous plants exhibit in increasing girth.
(b) secondary growth
(d) all the above
Ans. (b) secondary growth
3. That is involved in secondary growth are
(a) lateral meristems
(b) vascular cambium
(c) cork cambium
(d) all the above
Ans. (d) all the above
4. The merismetic layer that responsible for cutting of vascular tissues – xylem and phloem is called
(c) vascular cambium.
Ans.(c) vascular cambium
5. In dicot stems the cells of cambium present between primary xylem and primary phloem is the
(b) veins and midribs
(c) intrafascicular cambium
(d) sieve tubes elements
Ans.(c) intrafascicular cambium
6. The cells of medullary rays , adjoining intrafascicular cambium become merismetic and form the
(a) companion cells
(b) phloem fibres
(c) casparian strips
(d) interfascicular cambium
Ans.(d) interfascicular cambium
7. The cambium ring becomes active and begins to cut off new cells , both towards the inner and outer sides.The cells cut off towards pith, mature into
(a) companion cells
(b) secondary xylem
(c) bundle sheath cells
(d) cortical layers
Ans.(b) secondary xylem
8. The cambium rings becomes active and begins to cut off new cells , both towards the inner and the outer sides.The cells cut off towards pith mature into secondary xylem and the cells cut off towards periphery mature into
(a) secondary xylem
(b) secondary phloem
(d) circular shape
Ans.(b) secondary phloem
9. At some places the cambium forms a narrow band of parenchyma which passes through the secondary xylem and the secondary phloem in the radial directions. These are the
(a) monocotyledonous leaf
(b) dicotyledonous leaf
(c) secondary medullary rays
(d) companion cells
Ans. (c) secondary medullary rays
10. In the spring season, cambium is very active and producers large number of xylary elements having vessels with wider cavities . The wood formed during this season is called
(c) bulliform cells
(d) spring wood or early wood
Ans. (d) spring wood or early wood
11. in winter the cambium is less active and forms fewer xylary elements that have narrow vessels and this wood is called
(b) medullary rays
(c) autumn wood or late wood
(d) monocot leaves
Ans.(c) Autumn wood or late wood
12. The comparison between the spring wood and autumn wood is
a) the spring wood is lighter in colour and has a lower density.
b) the autumn wood is darker and has a higher density.
c) both a and b
Ans . (c) both a and b
13. The two kinds of woods that appears as alternate concentric rings constitute an
(a) sclerenchymatous cells
(b) annual ring
(c) cambium ring
(d) minimise water loss
An. (b) annual ring
14. Annual rings seen in a cut stem give in estimate of the
(b) age of the tree
(c) elongated cells
Ans. (b) age of the tree
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15. 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 our innermost layer of a stem .
These substances make it hard, durable and resistant to the attack of microorganisms and insects.
This region comprises dead elements with highly lignified walls and is called
(a) early wood
(c) late wood
Ans.(b) heart wood
16. The heart wood does not conduct water but it gives mechanical support to the stem. The peripheral region of the secondary xylem is lighter in colour and is known as the ….
(a) spring wood
(d) autumn wood
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