Please refer to Anatomy of Flowering Plants Class 11 Biology Exam Questions provided below. These questions and answers for Class 11 Biology have been designed based on the past trend of questions and important topics in your class 11 Biology books. You should go through all Class 11 Biology Important Questions provided by our teachers which will help you to get more marks in upcoming exams.
Class 11 Biology Exam Questions Anatomy of Flowering Plants
Class 11 Biology students should read and understand the important questions and answers provided below for Anatomy of Flowering Plants which will help them to understand all important and difficult topics.
Very Short Answer Type Questions:
Question. What is present on the surface of the leaves which helps the plant prevent loss of water but is absent in roots?
Ans. Cuticle It is a waxy coating covering the entire plant body surface. It is absent in roots, it prevents the loss of water through the surface of the plant body.
Question. What are the cells that make the leaves curl in plants during water stress?
Ans. Bulliform cells are bubble shaped cells present in grasses. Loss of turgor pressure in these cells causes leaf to curl during water stress, thus reduce transpiration.
Question. If one debarks a tree, what parts of the plant is being removed?
Ans. Debark means the removal of bark, i.e., all tissue exterior to the vascular cambium, including secondary phloem. Bark refers to a number of tissue types, viz., periderm (phellogen, phellem and phelloderm) and secondary phloem.
Question. What constitutes the cambial ring?
Ans. Interfascicular and intrafascicular cambia together form a ring of cambium called cambial ring. It is formed due to the meristematic activity of cambium.
The cambium which is found between the xylem and phloem is called fasicular or intrafasicular cambium and the newly formed cambium between the two vascular bundle is known as interfasicular cambium. Both type of cambium combine to form the cambial ring.
Question. Product of photosynthesis is transported from the leaves to various parts of the plants and stored in some cell before being utilised. What are the cells/tissues that store them?
Ans. The food gets stored in specialised parenchymatous cells present either in roots and stems or in their modifications in the form of a polysaccharide called starch.
Question. Give one basic functional difference between phellogen and phelloderm.
Ans. Phellogen is a meristematic tissue, while phelloderm is a permanent tissue. Phellogen (cork cambium) develops from the cortical cells, sometimes from pericycle cells. These cells actively divide and forms phellem on outerside and phelloderm (cortex cells)innerside on so phelloderm takes its origin from phellogen.
Question. What do hardwood and softwood stand for?
Ans. Distinguish between softwood and hardwood is as
Question. Protoxylem is the first formed xylem. If the protoxylem lies next to phloem what kind of arrangement of xylem would you call it?
Ans. It protoxylem lies next to phloem the condition of the xylem arrangement is called as exarch. It is found roots.
Question. What part of the plant would show the following?
(a) Radial vascular bundle
(b) Polyarch xylem
(c) Well developed pith
Ans. (a) Radial Vascular Bundle The xylem and phloem are present on the separate radii of the root. This arrangement of vascular bundle is known as radial vascular bundle.
(b) Polyarch Xylem When many strands of xylem are present, it is referred to as polyarch condition-a characteristic feature of monocot root.
(c) Well Developed Pith Dicot stem and monocot roots have well developed pith formed of parenchymatous cell with intercellular spaces..
Question. Arrange the following in the sequence you would find them in a plant starting from the periphery-phellem, phellogen, phelloderm.
Ans. Phellem or cork is the outer most layer, followed by phellogen (cork cambium) which in turn is followed by phelloderm (secondary cortex).
Question. What is the epidermal cell modification in plants which prevents water loss?
Ans. Bulliform cells check the water loss. Bulliform or motor cells are modified epidermal cells present in monocots or grasses. Under stressed conditions, they help in shutting down stomata and thus reduce water loss through transpiration.
Question. The cross-section of a plant material showed the following features when viewed under the microscope.
(a) The vascular bundles were radially arranged.
(b) Four xylem strands with exarch condition of protoxylem.
To which organ should it be assigned?
Ans. Root is the organ which shows the features given in the question. Vascular bundles are present on separate radii thus called radial arrangement. Protoxylem is towards periphery of root thus making exarch condition.
Question. What is the function of phloem parenchyma?
Ans. The main function of phloem parenchyma is to store food and other substances like resins, latex and mucilage. They also help in transport of food.
Short Answer Type Questions:
Question. Below is a list of plant fibres. From which part of the plant these are obtained
(a) coir (b) hemp (c) cotton (d) jute
Ans. (a) Coir It is a natural fibre obtained from husk of coconut. It is the fibrous mesoderm of the coconut fruit Cocos nucifera.
(b) Hemp The fibre is obtained from the stems of Cannabis sativa. It is the bast fibre (soft or stem fibre) obtained from secondary phloem.
(c) Cotton The fibre is the epidermal growth of cotton (Gossypium hirsutum) seed. It is elongated structure made up of cellulose.
(d) Jute It is a natural bast fibre obtained from Corchorus capsularis and made up of cellulose and lignin.
Question. What are the characteristic differences found in the vascular tissue of gymnosperms and angiosperms?
Ans. Difference between gymnosperm and angiosperm is as follows
Question. Write the precise function of
(a) sieve tube (b) interfascicular cambium
(c) collenchyma (d) aerenchyma
Ans. Sieve tube
It is present in the phloem tissue. It’s function is the transportation of synthesised food through out the plant.
Interfascicular Cambium
It’s function is to bring about secondary growth in the dicot stem and root. It is a kind of secondary meristematic tissue present in between two vascular bundles.
Collenchyma
It’s function is to provide mechanical support to young growing herbaceous stem. It’s cells have angular thickening at corners.
Aerenchyma
It provides buyoncy to the hydrophytic plants. It is a specialised parenchyma having large air spaces.
Question. Epidermal cells are often modified to perform specialised functions in plants. Name some of them and function they perform.
Ans. Modification of Epidermal Cells
The epidermal tissue has the following modifications
(i) Root hair
(ii) Epidermal Appendages
Question. While eating peach or pear it is usually seen that some stone like structures get entangled in the teeth, what are these stone like structures called?
Ans. The pulpy part of fruit of peach and pear, the stone cells are present, which are an sclerenchymatous cells and which are dead in nature. Their function is to give mechanical support to the soft tissue.
Question. Plants require water for their survival. But when watered excessively, plants die. Discuss.
Ans. Plants use water for several metabolic process as photosynthesis, transpiration and respiration. Plants die when watered in excess, because excess water removes the air trapped between the soil particles.
So, plant roots do not get O2 for respiration. Once root cells die, water and mineral absorption is stopped and this leads to gradual death of a plant.
Question. The stomatal pore is guarded by two kidney shaped guard cells. Name the epidermal cells surrounding the guard cells. How does a guard cell differ from an epidermal cell? Use a diagram to illustrate your answer.
Ans. The epidermal cells surrounding the guard cells of stomata are called subsidiary cells.
Differences between guard cells and epidermal calls are
Question. Point out the differences in the anatomy of leaf of peepal (Ficus religiosa) and maize (Zea mays). Draw the diagrams and label the differences.
Ans. Difference between Ficus leaf and maize leaf is as follows
Question. A transverse section of the trunk of a tree shows concentric rings which are known as growth rings. How are these rings formed? What is the significance of these rings?
Ans. Concentric Rings The concentric growth rings are called annual rings. These rings are formed due to the secondary growth. Secondary growth occurs in dicot trees due to the activity of cambium which is a meristematic tissue.
The rate of activity of cambium is more in spring so wood formed has larger wider xylem cells, whereas wood formed in winter has narrower and smaller xylem elements. This results in the formation of two rings called growth rings.
By counting these rings, age of the tree can be determined. This branch of science is known as dendrochronology or growth ring analysis.
Question. Trunks of some of the aged tree species appear to be composed of several fused trunks. Is it a physiological or anatomical abnormality? Explain in detail.
Ans. It is anatomical abnormality. It is an abnormal type of secondary growth, where a regular vascular cambium or cork cambium is not formed in its normal position. In case of old tree trunks, anomalous secondary growth produces cortical and medullary vascular bundles.
Thus, the additional or accessory vascular bundles given appearance of several fused trunks.
Question. What is the commercial source of cork? How is it formed in the plant?
Ans. The commerical cork is obtained from the cork tissue of Quercus suber, which yields bottle cork. Cork is formed by cork cambium or phellogen cell. Cork cambium cells divide periclinally, cutting cells towards the inside and outside. The cells cut off twowards the outside become suberised and dead.
These are compactly packed in radial rows without intercellullar spaces and form cork of phellem. Cork is impervious to water due to suberin and provides protection to the underlying tissues.
Question. Palm is a monocotyledonous plant, yet it increases in girth. Why and how?
Ans. Palms, despite being monocotylednous plant show secondary growth, i.e., increase in girth. This is due to the division and enlargement of parenchymatous cells in the ground tissue. Thus, repeated divisions cause increase in girth of stem and this type of growth is referred to as diffused secondary growth.
Question. The lawn grass (Cyandon dactylon) needs to be mowed frequently to prevent its overgrowth. Which tissue is responsible for its rapid growth?
Ans. The meristematic tissue is responsible for the rapid growth of such mowed lawn grass.
When the apex of grass is cut frequently, it leads to the growth of the lateral branches, that makes it more bushy.
Question. What is the difference between lenticels and stomata?
Ans. Difference between lenticels and stomata is as follows
Long Answer Type Questions:
Question. Deciduous plants shed their leaves during hot summer or in autumn. This process of shedding of leaves is called abscission. Apart from physiological changes what anatomical mechanism is involved in the abscission of leaves.
Ans. The process of shedding of leaves during hot summer or in autumn by deciduous plants is known as abscission. Anatomically, the cells of abscission zone are thin-walled and without deposition of lignin or suberin.
At the time of abscission, the middle lamella may dissolve between the cells of two middle layers but the primary wall remain intact. The middle lamella as well as the primary walls of the adjacent cells is dissolved. Ultimately the whole cells of middle layer found in the abscission layer gets dissolve completely.
Thus, there is separation of plant organ, i.e., leaf from the plant, wherever there is rainfall or wind.
Question. Each of the following terms has some anatomical significance. What do these terms mean? Explain with the help of line diagrams.
(a) Plasmadesmoses/Plasmodesmata
(b) Middle lamella
(c) Secondary wall
Ans. These terms mean as listed
Question. The arrangement of ovules within the ovary is known as placentation.
What does the term placenta refer to? Draw various types of placentations in the flower as seen in TS and VS.
Ans. Placenta are soft cushion like tissues with which the ovules are attached to the inner surface of ovary wall.
The arrangement of ovules within the ovary is known as placentation. The placentations are of different types, i.e., marginal, axile, parietal, basal and free central.
Marginal Placentation In this placentation, the placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge forming two rows, as in pea.
Axile Placentation In this placentation, the ovules are borne on central axis and the marginal of placenta grow in word and fuse, thus making a multilocular ovary, as in China rose, tomato, etc.
Parietal Placentation In this placentation, the ovules develop on the inner wall of the ovary or on peripheral part. Ovary is one chambered but it becomes two chambered due to the formation of a false septum known as replam, e.g., mustard.
Free Central Placentation In this type of placentation, the ovules are present on the central axis of ovary and septa is absent so ovary is unilocular, as in Dianthus and Primose.
Basal Placentation In this placentation, the placenta develops at the base of ovary and a single ovule is attached to it, as in sunflower.
Question. Is Pinus an evergreen tree? Comment.
Ans. Evergreen plant are those which has leaves persistent in all the four seasons. In contrast to deciduous plants which completely loose their foliage during winter or dry season. Pinus belonging to gymnosperms is an evergeen tree. The flowering plants under conditions of extreme cold shed their leaves and become dormant.
But Pinus due to the presence of bark, which is thick, needle-like leaves having sunken stomata, reduce the rate of transpiration. The cold areas are both physiologically and physically dry due to scanty rainfall, precipitation as snow, decreased root absorption at low temperature and exposed habitats.
But, Pinus is well adapted to such conditions. It continues to manufacture food during this period and grown to dominate other plants. This show that Pinus is an evergreen tree. It do not shed its leaves, i.e., needles under any condition.
Question. Distinguish between the following.
(a) Exarch and endarch condition of protoxylem
(b) Stele and vascular bundle
(c) Protoxylem and metaxylem
(d) Interfascicular cambium and intrafascicular cambium
(e) Open and closed vascular bundles
(f) Stem hair and root hair
Ans. Differences between the following
Question. Assume that a pencil box held in your hand, represents a plant cell. In how many possible planes can it be cut? Indicate these cuts with the help of line drawings.
Ans. A. If a plant cell is cut in different plane if result, in radial symmetry.
