NCERT Exemplar Solutions for class 11 Biology – Page 4

NCERT Exemplar Solutions for Class 11 Biology Chapter 7 Structural Organization in Animals

January 5, 2022September 7, 2018 by Raju

NCERT Exemplar Solutions for Class 11 Biology Chapter 7 Structural Organization in Animals

These Solutions are part of NCERT Exemplar Solutions for Class 11 Biology. Here we have given NCERT Exemplar Solutions for Class 11 Biology Chapter 7 Structural Organization in Animals.

VERY SHORT ANSWER QUESTIONS

Question 1.
State the number of segments in earthworm which are covered by a prominent dark band or clitellum.
Solution:
Segments 14-16 bare covered by a prominent dark band of glandular tissue called clitellum in a mature earthworm. It secretes mucus and albumen that help in formation of cocoon.
NCERT Exemplar Solutions for Class 11 Biology Chapter 7 Structural Organization in Animals 1.1

Question 2.
Where are sclerites present in cockroach?
Solution:
In all the body segments of cockroach sclerites are present. They are of two types dorsal sclerites often known as tergites, and ventral sclerites which are referred to as sternites.

Question 3.
How many times do nymphs moult to reach the adult form of cockroach?
Solution:
The nymph grows by moulting about 13 times to reach. In cockroach’, the development is indirect and paurometabous adult form has three stages, i.e., egg, nymph and adult. The nymph resembles adult except/or undeveloped wings and genitalia.

Question 4.
Identify the sex of a frog in which sound producing vocal sacs are present.
Solution:
Sex of frogs can be distinguished on the basis of presence of sound producing vocal sacs. These organs are present in males which make them crock lauder than females, so as to attract females for mating.

Question 5.
A muscle fibre tapers at both ends and does not show striations. Name the muscle fibre.
Solution:
Muscle fibres that taper at both the ends (fusiform) and do not show striations are smooth muscle fibres. They are also called involuntary muscles.

Question 6.
Name the different cell junctions found in tissues.
Solution:
The different cell junctions found in tissue include:
(i) Tight junctions are regions where plasma membrane of adjacent epithelial cells are held close together. They check the movement of material between then.
(ii) Gap junctions are meant for chemical exchange between adjacent cells.
(iii) Adhering junctions function to keep neighbouring cells together.

Question 7.
Give two identifying features of an adult male frog.
Solution:
The two identifying features of an adult male frog include
(a) Nuptial Pad is a copulatory pad present on the first digit of the forelimb of male frog and helps in closing female during amphelexus.
(b) Vocal Sacs are loose skin folds on throat of male frogs for producing louder croak to attract females for mating purposes.

Question 8.
Which mouth part of cockroach is comparable to our tongue?
Solution:
In cockroach, hypopharynx acts as a tongue and lies within cavity enclosed by the mouth parts.

Question 9.
The digestive system of frog is made of the following parts. Arrange them in an order beginning from mouth. Mouth, oesophagus, buccal cavity, stomach, intestine, cloaca, rectum, cloacal aperture.
Solution:
The correct arrangement of the part of digestive system in frog is
Mouth —> Buccal cavity —> Oesophagus —> Stomach —>Intestine —> Rectum —> Cloaca —> Cloacal aperture.

Question 10.
What is the difference between cutaneous and pulmonary respiration?
Solution:
In frog respiration takes place via the skin as well lungs.
Pulmonary respiration and occurs outside the water through lungs. Cutaneous respiration takes place in water as well as land, occurs through highly vascularised moist skin.

Question 11.
Special venous connection between liver and intestine and between kidney and intestine is found in frog, what are the called?
Solution:
In frog, venous connection between liver and intestine is called hepatic portal system and venus connection between the kidney and the lower parts of the frog is called renal portal system.

SHORT ANSWER QUESTIONS

Question 1.
Stratified epithelial cells have limited role in secretion. Justify their role in our skin.
The edible part of the peach or pear pome fruit for the fleshy thalamus.
Solution:

Stratified epithelium consists of epithelial cells in which the innermost layer is made up of columnar or cuboidal cells.
It is a type of compound epithelium and a waterproof protein called keratin is present few outer layers.
These layers of dead cells is called homy layer which is shed at intervals due to frictions and thus has a limited role in secretions and absorption.
The main function of stratified epithelium is to provide protection to the body against mechanical and chemical stresses.

Question 2.
How does a gap junctions facilitate intercellular communication ?
Solution:
Intercellular communication is facilitated by gap Junction allowing small signaling molecules to pass from cell to cell.
These are fine hydrophilic channels, between two adjacent animal cells that are formed with the help of two protein cylinders called connexus.
Each connexus consists of six proteins subunits that surround a hydrophilic channel. Opening or closing of channel is controlled by pH and Ca²⁺ ion concentration.

Question 3.
Why are blood, bone and cartilage called connective tissue?
Solution:

Connective tissue pt’ovides the structural framework and support to different organs forming tissue.
Blood is a fluid or vascular connective tissue, which connects various organs and transports substances from one place to another.
Bone is a solid, rigid and strong skeletal connective tissue, which supports the body and helps in locomotion.
Cartilage is also a skeletal connective tissue, not as rigid bone but piable and resists compression.
It plays role in support and protection and present in tip of nose, outer ear joints etc.

Question 4.
How do you distinguish between dorsal and ventral surface of the body of earthworm?
Solution:
The body of an earthworm can be distinguished into dorsal and ventral sides due to the presence of certain peculiar feature in it which include the following.
(i) The dorsal surface is darker than ventral surface because it is marked by a dark median mid dorsal line along the longitudinal axis of body. This is due to dorsal blood vessel, seen through integument.
(ii) Genital openings (pores), are present in the ventral surface of both male and female.
(iii) On vental surface genital papilla is located and helps in copulation.
NCERT Exemplar Solutions for Class 11 Biology Chapter 7 Structural Organization in Animals 1.2

Question 5.
Complete the following statement.
(a) In cockroach grinding of food particle is performed by ……..
(b) malpighian tubules help in removal of …….
(c) Hind gut of cockroach is differentiated into……
(d) In cockroach blood vessels open into spaces called ……
Solution:
(a) Gizzard is a muscular and greatly folded structure which marks the end of foregut in cockroach and bears six plates with teeth for crushing and grinding the food.
(b) Malpighian tubules are excretory in ‘ function as they help in the removal of
nitrogenous wastes in arthropods.
(c) Ileum, colon and rectum and rectum opens and through anus.
(d) Haemocoel is the body cavity of cockroach divided into sinuses and contains visceral organs of cockroach floating in haemolymph.

Question 6.
Mention special features of eye in cockroach. Discuss compound eye in arthropods and mention its structural features.
Solution:

In cockroach the eyes are large sessile, paired bean-shaped and present on either side of head.
The are compound in nature. Each compound eye consists of a large number of visual elements called ommatidia.
Each ommatidium is composed of a diopteric region and reticular (receptor) region. It is capable of producing a separate image of a small part of object seen.
Thus, the image of the object viewed consists of several pieces and is known as mosaic image.
Fine nerve fibres arise from the inner end of each ommatidium all of which combine to form one optic nerve connected to the brain.

Question 7.
Frog is a poikilotherm, exhibits camouflage and undergoes aestivation and hibernation, how are all these benficial to it?
Solution:

A trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection and evolution and help organism in its survival is an adapture triat.
Frog is a poikilotherm or a (cold blooded animal). It regulates its body temperature according to its environment.
It undergoes winter sleep (hibernation) for withstanding very cold temperatures and sujnmer sleep in hot temperatures (aestivation).
During this period, it lives in a dormant stage with very minimal vital body activities.
Frog is capable of changing its body colour as well, though gradually, with the change in its surrounding and climatic conditions.
This capability in frog is called as camouflage which lets it escape from the predators, an essential survival parameter for living.

Question 8.
Write the functions in brief in Column II, appropriate to the structures given in column I.
NCERT Exemplar Solutions for Class 11 Biology Chapter 7 Structural Organization in Animals 1.4
Solution:
(a) Nictitating Membrane in frog protects the eye from water and any damage by covering the eye ball of frog.
(b) Tympanum is present on each side of the frog head and is involved in the hearing process.
(c) Copulatory Pad present in the limbs of the male frog and helps in copulation by holding the female during its sexual activity.

Question 9.
Using appropriate examples, differentiate between false and true body segmentation.
Solution:

The serial repetition of similar body parts along the length of an animal is segmentation. The body of animals can be truely segmented or pseudo/false segmented.
True segmentation is found in annelids, arthropods and some chordates. In these organisms there is a linear repetition of body parts and each repeated unit is called somite (metamere).
In earthworms, the successive somites are externally and intemaly. ‘
Pseudosegmentation is seen when body is divided into number of false segments which are independent of each other.
Each segment is able to perform all the vital function of body. Growth occurs by the addition of new segments from the anterior end, e.g., tapeworm.

Question 10.
What is special about tissue present in the heart?
Solution:
Special tissue present in heart is called cardiac muscle, which has the following features
(i) Cardiac muscle fibres are supplied with both central and autonomic nervous system and are not under the control of will of animal.
(ii) These muscles show rhythmicity and are immune to fatigue.
(iii) They have a rich supply of blood.
(iv) They are myogenicas. They possess the property of contraction even if completely isolated from the body.
NCERT Exemplar Solutions for Class 11 Biology Chapter 7 Structural Organization in Animals 1.5

LONG ANSWER QUESTIONS

Question 1.
Comment upon the gametic exchange in earthworm during mating. Discuss the physiology in reproduction of earthworm.
Solution:
In earthworm mating is a unique process. Earthworm is a hermaphrodite. In which breeding takes place during rainy season and copulation begins soon after maturation of the sperms.
The gametic exchange and the physiology of reproduction during mating can described in the following manner.
(i) Earthworms are protandrous animal (i.e., maturation of sperm takes place much earlier then that of ova).
(ii) Mating process in earthworm occurs through process of cross-fertilisation.
(iii) The mating process involves exchange of gametic materials between the two worms.
(iv) Two individuals from adjacent burrows emerge half but and lie in contact with each other, and exchange packets of sperms called spermatophores opposite gonadal opening.
NCERT Exemplar Solutions for Class 11 Biology Chapter 7 Structural Organization in Animals 1.6
(v) The skin encircling male pore, elevates a little during the process to form a temporary papilla that fits like a penis into the opposite spermathecal pore to keep it open.
(vi) The copulating worm after filling of spermatheca moves a bit to adjust another pair of spermathecae to face the other male pores. This is accomplished in about an hour’s copulation.
(vii) The sperms mostly remain in their diverticula within the spermathecae and the ampulla is associated with the secretion of nutritive substances for the sperms.
(viii) The sperm and egg are passed into cocoon, secreted by clitellar gland.
(ix) Fertilisation is therefore external.

Question 2.
Explain the digestive system of cockroach with the help of labelled sketch.
Solution:
The alimentary canal of cockroach is divided
into three regions foregut, midgut and hindgut.
(i) Mouthy cavity, pharynx, oesophagus, crop and gizzard are included in foregut.
(ii) Mouth cavity is a small space, surrounded by mouth parts. Food is crushed and acted upon by the salivary secretion in mouth.
(iii) The mouth opens into a short tubular pharynx, leading towards the narrow tubular passage called oesophagus and then into a sac-like structure called crop which acts as a storage organ.
NCERT Exemplar Solutions for Class 11 Biology Chapter 7 Structural Organization in Animals 1.7
(iv) The crop is followed further by gizzard ‘ (proventriculus). Gizzard is composed of thick circular muscles and thick inner cuticle forming six highly chitinous plates called as teeth. It associated with the grinding and crushing of food particles. A thick cuticle lines the entire foregut.
(v) About one-third middle part of alimentry canal comprises of midgut or mesentron. The internal lining of midgut is an endodermal epithelium of columnal cells raised into several small villi like folds.
(vi) Anterior most part of midgut surrounding the stomadaeal valve is called cardia. Finger like blind processes called as enteric or hepatic caeca are present at the junction of foregut and midgut.
(vii) A ring of yellow filamentous structures is formed between the midgut and hindgut that aid in the removal of excretory products from haemolymph.
(viii) The remaining one-third posterior part of alimentary canal is Hindgut. It is relatively thicker than the midgut lined by cuticle and ectodermal epithelium.
(ix) Hindgut is diffrentiated into three parts anterior Ileum, middle colon and posterior rectum. Ileum is short and relatively narrower and its cuticie bears minute spines. Colon is the longest, relatively thicker and a coiled part of hindgut. Rectum is a small and oval chamber that opens out through anus.

We hope the NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 7 Structural Organization in Animals, help you. If you have any query regarding NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 7 Structural Organization in Animals, drop a comment below and we will get back to you at the earliest.

NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants

January 5, 2022September 7, 2018 by Raju

NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants

These Solutions are part of NCERT Exemplar Solutions for Class 11 Biology. Here we have given NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants.

VERY SHORT ANSWER QUESTIONS

Question 1.
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?
Solution:
The first product of photosynthesis is glucose. It is highly reactive molecule and gets converted into a disaccharide-sucrose for storage.
The food gets stored in specialised prarenchymatous cells present either in roots and stems or in their modifications in the form of a polysaccharide called starch.

Question 2.
Protoxylem is the first formed xylem. If the protoxylem lies next to pholem what kind of arrangement of xylem would you call it?
Solution:
The condition of the xylem arrangement if protoxylem lies next to phloem is called as exarch. It is found in roots.

Question 3.
What is the function of phloem parenchyma?
Solution:
The main function of phloem parenchyma is to store food and other substances like resins, latex and mucilage. They help in transport of food as well.

Question 4.
What is present on the surface of the leaves which helps the plant prevent loss of water but is absent in roots?
Solution:
Cuticle is a waxy coating covering the entire surface of the plant body. It is absent in roots, it prevents the loss of water through the surface of the plant.

Question 5.
What is the epidermal cell modification in plants which prevents water loss?
Solution:
Bulliform or motor cells are modified epidermal cells meant for checking water loss present in monocots or grasses. They help in shutting down stomata and thus reduce water loss through transpiration under stressed conditions.

Question 6.
What constitutes the cambial ring?
Solution:
The cambium present in between the xylem and phloem is called fasicular or intrafasicular cambium and the newly formed cambium between the two vascular bundle is known as interfascular cambium. Both type of cambium combine to form the cambial ring.

Question 7.
Give one basic functional difference between phellogen and phelloderm.
Solution:
Phelloderm is a permanent tissue while phellogen is a meristematic 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 so phelloderm originates from phellogen.
NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1.1

Question 8.
Arrange the following in the sequence you would find them in a plant starting from the periphery-phellem, phellogen, phelloderm.
Solution:
The outer most layer is phellem or cork followed by phellogen (cork cambium) which in turn is followed by phelloderm (secondary cortex.

Question 9.
If one debarks a tree, what parts of the plant is being removed?
Solution:
Debarking refers to removal of bark, i.e., all tissues exterior to the vascular cambium, including secondary phloem. Bark includes periderm (phellogen, phellem and phelloderm) and secondary phloem.

SHORT ANSWER QUESTIONS

Question 1.
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?
The edible part of the peach or pear pome fruit for the fleshy thalamus.
Solution:
The stone cells are present in the pulpy part of fruit of peach and pear. These are sclerenchymatous cells and which are dead in nature. They provide mechanical support to the soft tissue.
NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1.2

Question 2.
What is the commercial source of cork? How frs it formed in the plant?
Solution:
The source of commercial cork is the cork tissue of Quercus suber, which yields bottle cork. Cork is formed by cork cambium or phellogen cell, cells of cork cambium divide periclinally, cutting cells towards the inside and outside. The cells that cut off towards the outside become suberised and dead.
These are compactly packed in radial rows without intercellular spaces and form cork of phellem. Cork is impervious to water due to presence suberin and provides protection to the underlying tissues.

Question 3.
Below is a list of plant fibres. From which part of the plant these are obtained.
(a) Coir
(b) Hemp
(c) Cotton
(d) Jute
Solution:
(a) Coir is a natural fibre obtained from coconut husk. It is the fibrous mesoderm of the fruit of Cocos nucifera (coconut).
(b) Hemp fibre is obtained from the stems of Cannabis sativa. It is the bast fibre (soft or stem fibre) obtained from secondary phloem.
(c) Cotton fibre is the epidermal growth in cotton (Gossypium hirsutum) seed. It is an elongated structure made up of cellulose.
(d) Jute is a natural bast fibre made up of cellulose and lignin obtained from Corchorus capsularis.

Question 4.
Epidermal cells are often modified to perform specialised functions in plants. Name some of them and function they perform.
Solution:
The epidermal tissue system comprises of one cell thick layer of epidermal tissue and forms the outer most covering of the whole plant body. ,
Modification of Epidermal Cells
Following are the modifications of the epidermal tissue (i) root hair
Structure
These unicellular hairs are the extensions of epidermal cell of roots in the root hair zone.
NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1.3
Function
They increase the surface area for absorption of water and minerals.
(ii)Epidermal Appendages
Structure
These are called trichomes and are epidermal cell modifications. There any be unicellular or multicellular.
NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1.4
Appendages of epidermis of leaves
A-Stellate hair of a Alyssum
B-Glandular hair of Pelargonium
C-Short glandular hair of Lavandula
D-Floccose hair of Malva
E-Glandularhair of solanum
F-Urtivating hair of Verbascum
Function
They produce some glandular secretions.

Question 5.
The lawn grass (Cyandon dactyl on) needs to be mowed frequently to prevent its overgrowth. Which tissue is responsible for its rapid growth?
Solution:
The rapid growth of mowed lawn grass is due to meristematic tissue. When the apex of grass is cut frequently, it leads to the growth of the lateral branches, that makes it more bushy.

Question 6.
Plants require water for their survival. But when watered excessively, plants die. Discuss.
Solution:
Plants use water for several metabolic process as photosynthesis, transpiration and respiration. Plants when watered in excess die because excess water removes the air trapped between the soil particles.
The plant roots do not get 02 for respiration. Once cells of root die, water and mineral absorption is stopped and this leads to gradual death of a plant.

Question 7.
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?
Solution:

The concentric growth rings are called annual rings. These rings are formed due to the secondary growth.
Secondary growth occurs due to the activity of cambium which is a meristermatic tissue in dicot trees.
The rate of activity of cambium is more in spring so wood formed has larger wider xylem cells, whereas wood formed in autumn 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 8.
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.
Solution:
The appearance of several fused trunks 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. Anomalous secondary growth produces cortical and medullary vascular bundles in case of old tree trunks. Thus, the additional or accessory vascular bundles given appurtenance of several fused trunks.

Question 9.
What is the difference between lenticels and stomata? The gaseous exchange in all plants. Occurs by means of several openings present in the plant body.
Solution:
NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1.6

Question 10.
Write the precise function of
(a) sieve tube
(b) interfascicular cambium
(c) collenchyma
(d) aerenchyma
Solution:
Sieve tube It’s function is to transport of synthesised food throughout the plant. It is present in the phleom tissue.
NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1.7
Interfascicular Cambium It is a kind of secondary meristermatic tissue present in between two vascular bundles. It is function is to bring about secondary growth in the dicot stem and root.

Collenchyma cells have angular thickening at corners. There function is to provide mechanical support to young growing herbaceous stem.
NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1.9
Aeronchyma is a specilised parenchyma having large air spaces. It provides buyoncy to the hydrophytic plants.

Question 11.
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.
Solution:
Stematal apparatus is a special modification of epidermal tissue present over leaf area. The epidermal cells surrounding the guard cells of stomata are called subsidiary cells include.
Differences between guard cells and epidermal cells include:
NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1.11

LONG ANSWER QUESTIONS

Question 1.
Is Pirns an evergreen Tree? Comment.
Solution:

The plants which have persistent leaves in all the four seasons are evergreen. Deciduous plants in contrast completely loose their foliage during winter or dry season.
Pinus belonging to gymnosperms is an evergreen tree. Under conditions of extreme cold the flowering plants shed their leaves and become dormant.
In Pinus due to the presence of a thick bark thick needle-like leaves and sunken stomata to reduce the rate of transpiration the leaves we not shed.
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.
Pinus however is well adapted to such conditions. It continues to manufacture food during this period and grows to domiante other plants. This show that Pinus is an evergreen tree.
It does not shed its leaves or needles under any condition.

Question 2.
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.
Solution:
A. If a plant cell is cut in different plane if result, in radial symmetry.
NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1.12
B. If a plant cell is cut in two equal halves it result in bilateral symmetry.

Question 3.
Each of thefollowing terms has some anatomical significance. What do these terms mean? Explain with the help of line diagrams.
(a) Plasmodesmata
(b) Middle Lamella
(c) Secondary wall
Solution:
NCERT Exemplar Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1.14

We hope the NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 6 Anatomy of Flowering Plants, help you. If you have any query regarding NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 6 Anatomy of Flowering Plants, drop a comment below and we will get back to you at the earliest.

NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants

January 5, 2022September 7, 2018 by Raju

NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants

These Solutions are part of NCERT Exemplar Solutions for Class 11 Biology. Here we have given NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants.

VERY SHORT ANSWER QUESTIONS

Question 1.
Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of 02, root growth is restricted or completely stopped. How do, the plants growing in marsh lands or swamps obtain their 02 required for root respiration?
Solution:
The roots of the plants as Rhizophora that grow in marsh/swamp areas become negatively geotropic. They grow vertically upwards in air, above the soil level and respire. They are thus called respiratory roots or pneumatophores.

Question 2.
In Opuntia, the stem is modified into a flattened green structure to perform the function of leaves, (i.e., photosynthesis). Cite some other examples of modifications of plant parts for the purpose of photosytnthesis.
Solution:
In Opuntia a xerophytic plant leaves are modified into spine to reduce the rate of transpiration and they do not perform the photosynthesis at all.
The function of photosynthesis in Opuntia plant is performed by stem which is thick fleshy and flattened structure containing chlorophyll and stores food and known as phylloclade.
In some plants similarly roots become assimilatory e.g., case of Trapa and Tinospom. These roots grow outside the soil, develop chlorophyll in them and perform photosynthesis.

Question 3.
In swampy areas like the sunderbans in West Bengal, plants bear special kind of roots called……
Solution:
Pneumatophores Roots are meant for the absorption of water and minerals from the soil. Cells of roots require 02 to respire. In swampy areas, soil does not have air, so no 07 is available to them.
In such cases, roots come out of the soil showing negative geotropism and breathe after coming in contact with air, e.g., Rhizophora. Such roots are called pneumatophores or respiratory roots.

Question 4.
In aquatic plants like Pistia and Eichhornia, leaves and roots are found near…..
Solution:
In Pistia and Eichhonia, the stem is like a runner where it branches to form leaves at the
v apex and roots below. Both the plants are hydrophytes and thus the roots are found near the surface of water.

Question 5.
Which parts in ginger and onion are edible?
Solution:
The edible part of ginger is rhizome the modified stem which stores food material whreas the edible part in onion is fleshy leaves, where the internode becomes shortened, leaves get condensed to form a tunic and store food material.

Question 6.
In epigynous flower, ovary is situated below the……….. .
Solution:
Ovary is situated below the thalamus (inferior) in epigynous flower while the other whorls of flower like sepals, petals and androecium grows above the ovary (superior), e.g., carrot, guava, Cucurbit a, sunflower, etc.
NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 1.1

Question 7.
Add the missing floral organs of the given floral formula of Fabaceae.

Solution:
The floral formula of fabaceae family is

The flower of fabaceae is bisexual, zygomorphic, pentameros, gamosepalous, corolla-petals 5, androecium is ten diadelphous, gynoecium- superior, ovary monocarpellay.

SHORT ANSWER QUESTIONS

Question 1.
Give two examples of roots that develop from different parts of the angiospermic plant other than the radicle.
Solution:
Prop roots are meant for support. Prop roots develop from the lower nodes of stem of banyan tree. They grow downwards and touch the soil.
Stilt roots arise from the lower nodes of stem in sugarcane and enter the soil to provide strength to the plant. These protect the plant against winds.
NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 1.3

Question 2.
The essential functions of roots are anchorage and absorption of water and minerals in the terrestrial plant. What functions are associated with the roots of aquatic plants. How are roots of aquatic plants and terrestrial plants different?
Solution:
Usually the terrestrial roots show a branched network that helps in anchorage and absorption of water and minerals from soil to the plant. While in aquatic plants, roots show modification and deviation from their normal function.
Ex – in plants like Trapu, Tinospora the roots are green and highly branched to increase the photosynthetic area, whereas in plants like Jussiaecci they get inflated due to air project out of water so a to help the plant in floating and exchange of gases.
Difference between roots of aquatic plants and terrestrial plants are as:
NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 1.4

Question 3.
Draw diagrams of a typical monocot and dicot leaves to show their venation pattern.
Solution:
The pattern of distribution of veins and veinlets in the lamina of leaf is called Venation. It’s pattern is different in monocot and dicot leaf.
NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 1.5

Question 4.
A typical angiosperm flower consists of four floral parts. Give the names of the floral parts and their arrangements sequentially.
Solution:
Following are the four floral parts of typical angiospermic flower.

Calyx is the outermost whorl of the flower and comprised of sepals. These are usually green and (in bud stage) are protective in function.
Corolla is composed of petals, usually bright coloured to attract insects for pollination.
Androecium is composed of stamens, the male reproductive organ. Each stamen consists of stalk or filament and anther (containing pollen sac and pollen grains).
Gynoecium is the female reproductive part and comprised of one or more carpels. Each

Question 5.
Reticulate venation is found in dicot leaves while in monocot leaves venation is of parallel type. Biology being a ‘Science of exceptions’, find out any exception to this generalisation.
Solution:
Reticulate venation is a characteristic of dicots and parallel venation is of monocots. But few exceptions are also seen in this generalisation, parallel venation is also found in dicot plants, e.g, Calophyllum, Corymbium, etc and reticulate venation is also found in monocot plants such as Alocasia, smilax, etc.

Question 6.
You have heard about several insectivorous plants that fee on insects. Nepenthes or the pitcher plant is one such example, which usually grows in shallow water or in march lands. What part of the plant is modified into a pitcher? How does this modification help the plant for food even though it can photosynthesise like any other green plant?
Solution:

In insectivorous plant like Nepenthes, the leaf lamin is modified to form a pitcher and anterior part of petiole coils like tendril which keeps the pitcher in a vertical direction.
Posterior part of the petiole remains flattened like a leaf. The apex of lamina forms a lid.
Pitcher contains digestive enzyme for digesting trapped insects.
All these modifications and adaptations are developed to make up for the nitrogen deficiency in the plant because these plants are found in N2 deficient soil, (marshy/swamp soils).

Question 7.
How can you differentiate between free central and axile placentation?
Solution:
The arrangement of ovules on the walls of ovary with the help of special kind of tissue called placenta is placentation. Plants show different types of placentation.
Difference between free central placentation and axile placentation include:
NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 1.8

Question 8.
Why is maize grain usually called as a fruit and not a seed?
Solution:
The maize grain is usually known as fruit because it is a ripened ovary which contains a ripened ovule, e.g., a single seed. This fruit is known as caryopsis in which the pericarp is fused with the seed coat. The maize grain occurs attached to a thick cob or peduncle.

Question 9.
Tendrils of grapevins are homologous to the tendril of pumpkins, but are analogous to that of pea. Justify the above statement.
Solution:
Homologous organs are organs that have similar origin but they differ functionally. Axillary bud of stem gives rise to tendril of both grapevine and pumpkins so they have same origin, i.e., homologous, whereas analogous organs are organs having different origin, but perform same function. The tendril of pea arises from the leaf and helps the plant to climb.

Question 10.
Rhizome of ginger is like the roots of other plants that grows underground. Despite this fact ginger is a stem and not a root. Justify.
Solution:
Rhizome of Ginger is a type of modified underground stem which grows horizontally underground and bears nodes, intemodes and scaly leaves and buds, which gives rise to aerial shoots.
The adventitious root arises from the lower surface of nodes. It is not a true root because root does not have nodes and intemodes. The rhizome does not perform the function of anchorage and absorption, rather serve as reservoir for food storage. All these characteristics support the fact that ginger is a stem and not a root.
NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 1.10

LONG ANSWER QUESTIONS

Question 1.
Distinguish between families – Fabaceae, solanaceae, Liliaceae on the basis of gynoecium characteristics (with figures). Also write economic importance of any one of the above family.
Solution:
The families in plant kingdom mainly differ from each other in their reproductive structures.
Based on characteristics of gynoecium the difference between the three families include the following:
NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 1.11

Question 2.
Describe various stem modifications associated with food storage climbing and protection.
Solution:
The aerial part of plant bearing nodes, intemodes, buds, flowers, fruits and seeds is stem. Besides these functions and forms, it gets modified and perform under spfccial conditions.
The various stem modifications include:
NCERT Exemplar Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 1.13

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NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom

January 5, 2022September 7, 2018 by Raju

NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom

These Solutions are part of NCERT Exemplar Solutions for Class 11 Biology. Here we have given NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom.

VERY SHORT ANSWER QUESTIONS

Question 1.
What is the importance of pneumatic bones and air sacs in Aves?
Solution:
Birds possess light wfi’ght bones that contain internal spaces filled with air, which are pneumatic bones. They are an adaptation for flight as they help in, reducing the body weight. Aerodynamic lungs with specialized air sacs are an additional feature that aids birds in flying (e.g., bald eagle, pigeon).

Question 2.
What is metagenesis? Mention an example which exhibits this phenomenon.
Solution:
The phenomenon in which one generation of certain plants and animals reproduce asexually, followed by the sexually reproducing generation is metagenesis. Both the forms in metagenesis are diploid hence, it is known as the false alternation of generation. Coelenterates exhibit metagenesis (e.g., Obelia) where in its life cycle polyp form alternates with medusa.

Question 3.
What is the role of feathers?
Solution:
Feathers are the epidermal out growths that form distinctive outer covering or plumage in birds.
A variety of role are played by feathers which includes:
(i) They provide life and help in flight, by creating airfoil shape for wings.
(ii) They help in maintaining body temperature.
(iii) Feathers play a vital role in mating by providing secondary sexual that characters in both the sexes the colour and markings determine the alteractiveness of mate.

Question 4.
Which group of chordates posses sucking and circular mouth without jaws?
Solution:
Class-Cyclostomata is comprised of living jawless fishes. They have a circular mouth and lack jaws, hence they are also called agnathans. The mouth works like a sucker and is surrounded by tentacles (e.g., lampreys and haglish). These also prosses rectroctable teeth that are homy.

Question 5.
Mention two modifications in reptiles required for terrestrial mode of life.
Solution:
Certain characters acquired by reptiles for the terrestrial adaptations include.
(i) Body is covered with dry and comified skin and epidermal scales or scutes.
(ii) Internal fertilisation.

Question 6.
What is the role of radula in molluscs?
Solution:
The radula is a special rasping structure present many molluscs. It is used to scrape and scratch the food and to create depressions in rocks used as habitat.
It bears many rows of tiny teeth that are replaced
as they wear down e.g., Limplet is a marine invertebrate that uses its radula for creating home by boring a shallow hole in the rock.

Question 7.
Name the animal, which exhibits the
phenomenon of bioluminescence. Mention the
phylum to which it belongs.
Solution:
Bioluminescence is the phenomenon of production and emission of light by an organism as a result of chemical reaction during which chemical energy is converted to light energy. The phenomenon of bioluminescence is exhibited by Ctenoplana from phylum- Ctenophora.

Question 8.
Write one example for each of the following in the space providing.
(a) Cold blooded animal
(b) Warm blooded animal
(c) Animal possessing dry and comified skin
(d) Dioecious animal
Solution:
(a) A cold blooded animal is Crocodilus (crocodile)
(b) Elephas maximus (elephant), (mammal) is a warm blooded animal.
(c) Testudo (tortoise) bears dry and comified skin.
(d) Ascaris (roundworm) is a dioecious animal.

Question 9.
Differentiate between a diplobastic and triploblastic animal.
Solution:
Diploblastic animals are animals in which the cells are arranged in two embryonic layers, an external ectoderm and an internal endoderm (e.g., coelentrates). Animals in which the developing embryo has a third germinal layer, i. e., mesoderm lying between the ectoderm and endoderm are calledtriploblastic animals, (e.g., chordates).

Question 10.
Give an example of the following
(a) Roundworm
(b) Fish possessing poison sting
(c) A limbless reptile/amphibian
(d) An oviparous mammal
Solution:
(a) Roundworm – A scans
(b) Fish possessing poison sting – Trygon
(c) A limbless reptile/amphibian – Ichthyophis
(d) An oviparous mammal – Duck billed platypus.

Question 11.
Provide appropriate technical term in the space provided.
(a) Blood-filled cavity in arthropods
(b) Free-floating form of cnidaria
(c) Stinging organ of jelly fishes
(d) Lateral appendages in aquatic annelids
Solution:
(a) The blood-filled cavity in arthropods containing haemolymph is haemocoel.
(b) A form in cnidarians in which the body is shaped like an umbrella which can float freely in sed water is medusa.
(c) Capsules of specialised cells in cnidarians which act as a paraylysing sting are nematocytes.
(d) The paired unjointed lateral outgrowth in annelids bearing chaetae are parapodia.

Question 12.
Match the following.
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.1
Solution:
A. —> (iii)
B. —> (i)
C. —> (iv)
D. —> (ii)
(a) Octopus The appendages in invertebrates that are used for grasping food and for locomotion are tentacles.
(b) Crocodile for locomotion, and swimming limbs are used.
(c) Catta Fins are means of locomotion and are used to generation optimum thrust thus controlling the subsequent motion.
(d) Ctenoplana Locomotory organs formed by strong cilia with fused bases are comb plates.

SHORT ANSWER QUESTIONS

Question 1.
Differentiate between
(a) Open circulatory system and closed circulatory system.
(b) Oviparous and viviparous characteristic.
(c) Direct development and indirect development.
Solution:
Differentiation between these are as below
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.2

Question 2.
There has been an increase in the number of chambers in heart during evolution of vertebrates. Give the names of the class of vertebrates having two, three or four chambered heart.
Solution:
(a) In organisms like fishes two chambered heart is present. Mixing of oxygenated and deoxygenated blood blood occurs as only one atria and one ventricle is present which are not separated.
(b) After division of auricle into right and left halves three chambered heart develops and in amphibian. In ventiricles mixing of oxygenated and deoxygenated blood occurs.
(c) In reptilies an intermidiary heart is present in which ventricles get partially divided through a septum which is incomplete thus having a false four-chambered heart e.g., Crocodiles.
(d) Both the auricle and ventricle are divided into two halves in four chambered heart and so no mixing of oxygenated and deoxygenated blood occurs, e.g., birds and mammals.

Question 3.
Fill up the blank spaces appropriately
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.3
Solution:
Excretion involves the elimination of metabolic waste products from the animal body. In the process of excretion in different animals different organs are involved.
(a) In arthropods excretory products from haemolymph are removed by the malpighian tubules.
(b) The excretory organ occurs as segmentally arranged coiled tubules called nephridia in annelids.
(c) Excretion occurs by paired structures called organ of Bojanus in molluscs also called metanephridia.
(d) Mesonephric kidneys are associated with excretion in amphibians.
The circulation of blood and lymph along with oxygen carbondioxide, hormones, blood cells, etc, within the body system for the nourishment of cells, fighting diseases, and for stabilising body temperature and pH is involved blood circulation.
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.4

Respiratory organs are involved in the
exchange of gases from the atmosphere.
Different respiratory organs in various animals.
(a) Lungs and skin in amphibians.
(b) Lung/gills/tracheal system in arthropoda and molluscs.
(c) Skin in annelids.

Question 4.
Match the following
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.5

Solution:
A. —> (v)
B. —> (iii)
C. —> (ii)
D.—> (i)
E. —> (vi)
F. —> (iv)
A. Amphibians are found in both aquatic and terrestrial habitat. Their large is completely aquatic while adult lives in terrestrial as well as in aquatic habitat.
B. Mammals produce milk in the mammary glands and feed their young one. The mammary glands are enlarged exocrine modified sweat glands functional in female mammals.
C. Chondrichthyes have (notochord) in the young stage which is gradually replaced by cartilage.
D. Osteichthyes possess air bladder which is a vesicle or sac containing air.
E. Cyclostomes have sucking and circular mouth without jaws which is surrounded by tentacles and the tongue bears teeth, e.g., lamprey and hagfish.
F. Aves comprise of light weighted bones with internal spaces field with air called pneumatic bones and aerodynamic lungs with specialised air sacs. These are the adaptations which enable birds to fly.

Question 5.
Endoparasites are found inside the host body. Mention the special structure, possessed by these and which enables them to survive in those conditions.
Solution:
Endoparasites such as Taenia solium and Fasciola hepatica (liver fluke), etc., are found inside body the host and survive due to the presence of certain characters.
Endoparasites special characters which include:
(i) The is respiration is anaerobic and the gaseous exchange in via general body surface.
(ii) They bear additional organs for the attachment to the host. Taenia solium posses hooks and suckers for the attachment with the host. Fasciola hepatica possesses acetabulum or posterior sucker for the attachment.
(iii) they have well developed reproductive organs. They are generally, harmaphrodite and self fertilisation occurs commonly.
(iv) They have a thick tegument (body covering) which is resistant to the host’s digestive enzymes and antioxins.
(v) Locomotary organs are absent.
(vi) They lack digestive organs because digested and semi digested food of the host is directly absorbed through their body surface.

Question 6.
Mention two similarities between
(a) Aves and mammals
(b) A frog and crocodile
(c) A turtle and Pila
Solution:
(a) Following are the similarities between aves and mammals
(i) Presence of four chambered heart.
(ii) The members of both the groups are homeotherms, i.e., warm blooded. They are able to maintain constant body temperature.
(b) Similarities between frog and crocodile include:
(i) They are cold blooded animals. The members of both the groups are poikilotherms, i.e., they lack the capacity to regulate their body temperature.
(ii) Frogs and crocodiles are oviparous animals.
(c) Similarities between turtle and Pila include
(i) Body is covered with dry and comified skin in both animals. In turtle, the epidermal covering is known as scales whereas in case of Pila, it is known as calcareous shell.
(ii) Both animals are oviparous.

Question 7.
Name
(a) A limbless animal
(b) A cold blooded animal
(c) A warm blooded animal
(d) An animal possessing dry and comified skin
(e) An animal having canal system and spicules
(f) An animal with cnidoblasts
Solution:
(a) Ichthyophis does not possess limbs.
(b) A cold blooded animal scoliodon (dog fish).
(c) warm blooded animal is Columba (pigeon).
(d) Naja naja (snake) possesses dry and cornified skin.
(e) Sycon (sponge) possesses canal system and bear spicules.
(f) Obelia bears cnidoblast.

Question 8.
Excretory organs of different animals are given below. Choose correctly and write in the space provided.
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.6

Solution:
Metabolism in body leads to the formation of waste that can affect body’s vital organs so it has to be removed from body. Different classes of organisms possess different types of excretory organs to eliminate the byproduct of metabolism.
A. —> (vi)
B. —> (ii)
C. —> (v)
D. —> (iii)
E. —> (vi)
F. —> (i)
A. Balanogolossus – Proboscis glands. This gland excretes brown granules and is present in front of central sinus.
B. Nephridia in Leech. It helps in osmoregulation and excretion.
C. Malpighian tubules in Locust open into gut and help in excretion.
D. The Flame cells of liver fluke are specialised cells in Platyhelminthes which helps in osmoregulation and excretion. These are also called protonephridia.
E. Sea urchin-absent Specialised excretory organs are absent in sea urchin.
F. It TV/a-Metanephridia is a type of excretory gland or nephridium found in many types of invertebrates such as annelids, arthropods, and molluscs (in molluscus nephridia is also known as Bojanus organ).

LONG ANSWER QUESTIONS

Question 1.
What is the relationship between germinal layers and the formation of body cavity in case of coelomate, acoelomates andpseudocoelomates?
Solution:
Multicellular organisms typically possess a concentric arrangement of tissues in the body. These tissues are derived from the three embrycnio cell, layers called germinal layers.
(i) The outer layer is the ectoderm, the middle layer is the mesoderm and the innermost layer is the endoderm.
(ii) Ectoderm is associated with the formation of CNS, eye lens, ganglia, nerves and glands.
(iii) Mesoderm forms the that in structural components of the body like the skeletal muscles the skeleton, the dermis of the
skin connective tissue, etc.
(iv) Endoderm layer is associated with the formation of the stomach, colon, liver, pancreas urinary bladder and other vital organs is an organism.
(v) Coelom is the body cavity that is lined by mesoderm and the animals possessing coelom are called as ceolomates. e.g., phylum-Annelida, Mollusca, Arthropoda, Echnidermata, Hermichordata and Chordata.
(vi) In some organisms, body cavity is not lined by mesoderm, instead mesoderm is present in the form of scattered pouches in between ectoderm and endoderm, Such body cavity is called pseudocoelom and animals possessing there stusturs are refered to as pseudocoelomates e.g., As car is.
(vii) The animals in which there is complete absence of body cavity are called acoelomates. e.g., Platyhelminthes.
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.7

Question 2.
Comment upon the habitats and external features of animals belonging to class- Amphibia and Reptilia.
Solution:
Amphibians
(i) They can dwell in aquatic as well as terrestrial habitats. They are ectothermic or (cold blooded).
(ii) They are tetrapods having (4 limbs) which facilitate movement on land.
(iii) Their limbs have evolved from the pectoral and pelvic fins.
(iv) Skin is thin, covered by mucus and remains mostly moist. It also serves as an accessory source of oxygen.
(v) They breathe through gills and lung gills usually appear in the larval stage, replaced by lungs in the adults stage.
(vi) Their heart is three chambered with two atria and one ventricle.
(vii) Females are oviparous and fertilisation is mostly external.
(viii) Larva is a tadpole, which metamorphose into adult e.g., Rariu frog, Nectureus (mud puppy), Salamandera (salamander).
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.8
Reptiles
(i) They are mostly terrestrial animals and their body is covered by dry, and comified skin, epidermal scales or scutes.
(ii) In reptiles the mode of locomotion is creeping and crawling.
(iii) Lungs are well developed and present in all stages of life.
(iv) Claws are present in toes.
(v) s Appendages are well adapted for land movement.
(vi) Heart possesses a partially divided ventricle and 2 atria.
(vii) They lay amniotic eggs which are inclubated on land.
(viii) They are poikilothermic or cold blooded animals. Temperature is regulated mechanically and not metabolically by moving in and out; source of heat is usually the sun.
(ix) Fertilisation is internal. They are oviparous and development of young ones is direct e.g., Chelone (turtle), Naja (cobra), Crocodicus (crocodile).
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.9

We hope the NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 4 Animal Kingdom, help you. If you have any query regarding NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 4 Animal Kingdom, drop a comment below and we will get back to you at the earliest.

NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom

January 5, 2022September 7, 2018 by Raju

NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom

These Solutions are part of NCERT Exemplar Solutions for Class 11 Biology. Here we have given NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom.

VERY SHORT ANSWER QUESTIONS

Question 1.
Food is stored as floridean starch in Rhodophyceae. Mannitol is the reserve food material of which group of algae?
Solution:
Mannitol is a reserve food material of the members of Phaeophyceae (brown algae).

Question 2.
The plant body in higher plants is well differentiated and well developed. Roots are the organs used for the purpose of absorption. What is the equivalent of roots in the less developed lower plants?
Solution:
Root like structure called rhizoids are present instead of roots in less developed lower plants (bryophytes and pteridophytes). The plant tissue system in these is not differentiated into true leaf, stem and roots as it is found in higher plants (gymnosperm and angiosperm).

Question 3.
Most algal genera show haplontic life style. Name an alga which is
(a) Haplo diplontic
(b) Diplontic
Solution:
Haplo diplontic type of life cycle is exhibited by Ectocarpus, Polysiphonia and Kelps. The main plant body is saprophytic in Fucus and it shows diplontic type of life cycle.

Question 4.
In bryophytes male and female sex organs are called …………….. and …………..
Solution:
In bryophytes the male sex organ in antheridium and female sex organ is archegonium.
Antheridium produces flagellate antherozoids which are male gametes.
Archegonia is the female part which bears a single egg cell.

SHORT ANSWER QUESTIONS

Question 1.
Why are bryophytes called the amphibians of the plant kingdom? Amphibians can their in water as well as on terrestrial habitat.
Solution:
Bryophytes are a group of primitive plants having a dominant gametophytic plant body. These plants can live in soil but depend on water for movement of male gametes called antherozoids to reach the archegonium (female organ bearing egg cell) so that fertilisation can occur, so bryophytes are called the amphibians of the plant kingdom.

Question 2.
Heterospory, i.e., formation of two types of spores— microspores and megaspores is a characteristic feature in the life cycle of a few members of pteridophytes and all spermatophytes. Do you think heterospory has some evolutionary significance in plant kingdom?
Solution:

The production of spores of two different sizes and sexes by the sporophytes of land plants is heterospory. Two types ofspores are produced by heterosporic plants.
Small spores are microspores which germinate into the male gametophyte and large spores are macrospores which develop into the female gametophyte.
Pteridophytes are intermediate between bryophytes and gymnosperms in the evolution of plants.
All bryophytes are homosporous and all gymnosperms are heterosporous. This condition is advanced as sexual dimorphism results in cross fertilisation.
Primitive or earlier pteridophytes are homosporous while later pteriodophytes are heterosporous e.g., Dryopteris, Pteris homosporous Selaginella, Sn/vrao-heterosporous.

Question 3.
Each plant group of plants has some phylogenetic significance in relation to evolution Cycas, one of the few living members of gymnosperms is called as the ‘relic of past’. Can you establish a phylogenetic relationship of Cycas with any other group of plants that justifies the above statement?
Solution:
Cycas is an evergreen plant which resembles palm. It has an unbranched stem and large compound leaves. It exhibits phylogenetic relationship with pteridophyte. Its evolutionary characters include thefollowing:
(i) Growth is redundant.
(ii) Shedding of seed while the embryo is still immature.
(iii) Minimal secondary growth and manoxylic wood.
(iv) Megasporophylls are leaf like.
(v) Sperms are flagellate even when pollen tube is present.
(vi) Leaf bases are persistent.
(vii) Ptysix is circinate.
(viii) Arrangement of microsporangia in well defined archegonia.

Question 4.
Comment on the life cycle and nature of fem prothallus.
Solution:
The life cycle of ferm (Dryopteris) clearly depicts the alternation of generation. The gametophytic stage (n) alternates with the sporophytic stage (2n) in the life cycle as shown in the figure.
NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1.1
The prothallus of the fem is a multicellular, free living, thalloid, haploid and autotrophic structure. It develops from the spores produced by sporophyte after reduction division.
These spore germinate within a germtube with an apical cell and forms a filament of 3-6 cells and one or two rhizoids at the base which later develops into gametophytic plant.
NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1.2

Question 5.
How are the male and female gametophytes of pteridophytes and gymnosperms different from each other?
Solution:
The male and female gametophytes of pteridophytes and gymnosperms different from each other as:
NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1.3

Question 6.
How are the male and female gametophytes of pteridophytes and gymnosperms different from each other?
Solution:

Symbiosis is a type of interaction of two living organisms where both the associated partners derive some benefit from each other both co¬exist and flourish well.
Mycorrhiza is a symbiotic association between fungus and the roots of vascular plants. The fungus colonizes the roots of the host either intra or inter cellularly. It helps in the nutrient absorption from soil for the plant.
Mycorrhizal associations are present in conifers, i.e.,Pinus, Cedrus, Abies and Picea.
Coralloid roots develop in Cycas. It is produced in clusters at the base of the stem and protrudes out on the ground.
It is dichotomously branched and greenish in colour. It contains algal zone in cortex.
This algal zone contains blue green algae like Anabaena and Nostoc which grow in symbiotic association with coralloid roots.

LONG ANSWER QUESTIONS

Question 1.
Explain why sexual reproduction in angiosperms is said to take place through double fertilisation and triple fusion. Also draw a labelled diagram of embryo sac to explain the phenomena.
Solution:

An angiospermic plants reproduces sexually by the formation of male and female gametes.
The male gamete is a pollen which contains two male nuclei and the female gamete is an egg cell produced in ovule (female gametophyte).
The pollen grains germinate on the stigma of a flower and the results in growth of pollen through the tissues of stigma and style and reach the egg apparatus.
The two male gametes are discharged within the embryo sac. One of the male gamete fuses with the egg cell to form a diploid zygote.
This’fusion is known as fertilisation or syngamy. The second male gamete fuses with the diploid secondary nucleus and forms the triploid Primary Endosperm Nucleus (PEN). This fusion is known as triple fusion.
Because of the involvement of two fusion, this event in angiosperms is termed as double fertilisation. The zygote then develops into embryo and PEN develops into endosperm which provides nourishment to the developing embryo.

Question 2.
Draw labelled diagrams of
(a) Female and male thallus of a liverwort.
(b) Gametophyte and sporophyte of Funaria.
(c) Alternation of generation in angiosperm.
Solution:
NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1.5
(a) Liverworts
(i) Male thallus of Marchantia polymorpha
(ii) Female thallus of Marchantia polymorpha
(b) Funaria
(gametophyte and sporophyte)

We hope the NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 3 Plant Kingdom, help you. If you have any query regarding NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 3 Plant Kingdom, drop a comment below and we will get back to you at the earliest.