NCERT Solutions for Class 11 Science Biology Chapter 5

Question 1:

Rearrange the following zones as seen in the root in vertical section and choose the correct option.
A. Root hair zone
B. Zone of meristems
C. Root cap zone
D. Zone of maturation
E. Zone of elongation

a. C, B, E, A, D
b. A, B, C, D, E
c. D, E, A, C, B
d. E, D, C, B, A

Answer:

The root can be differentiated into five distinct regions. The root cap zone (C) is a tip, followed by the zone of cell division called the meristematic region (B). This is followed by the region of elongation (E), followed by the region of unicellular root hairs(A), and lastly, there is a zone of maturation (D).

Hence, the correct answer is option a.

Question 2:

In an inflorescence where flowers are borne laterally in an acropetal succession, the position of the youngest floral bud in the floral axis shall be
a. Proximal
b. Distal
c. Intercalary
d. Any where

Answer:

In acropetal succession, the older flowers are at the base and the younger flower is at the tip. This type of arrangement of flowers occurs in the racemose type of inflorescence, where the terminal bud continues to grow and the main axis has indeterminate growth.

Hence, the correct answer is option b.

Question 3:

The mature seeds of plants such as gram and peas, possess no endosperm, because
a. These plants are not angiosperms
b. There is no double fertilization in them
c. Endosperm is not formed in them
d. Endosperm gets used up by the developing embryo during seed development

Answer:

In dicot plants like gram and peas, the endosperm gets used up by the developing embryo during seed development and so, the two cotyledons contain the stored food reserves of the seed.

Hence, the correct answer is option d.

Question 4:

Roots developed from parts of the plant other than radicle are called
a. Taproots
b. Fibrous roots
c. Adventitious roots
d. Nodular roots

Answer:

The root that arises from any other part of the plant other than the radicle or the root axis, they are called adventitious root. Their development can also be induced in response to adverse environmental conditions or stresses.

Hence,the correct answer is option C.

Question 5:

Venation is a term used to describe the pattern of arrangment of
a. Floral organs
b. Flower in infloresence
c. Veins and veinlets in a lamina
d. All of them

Answer:

Venation is the arrangement of the veins and the veinlets in the lamina of the leaf. Their are two types of leaf venation- Reticulate and parallel. When the veinlets form a network, the venation is termed reticulate venation. When the veins run parallel to each other within a lamina, the venation is termed parallel venation. The leaves of dicotyledonous plants possess reticulate venation, while parallel venation is the characteristic of most monocotyledons.

Hence, the correct answer is option c.

Question 6:

Endosperm, a product of double fertilization in angiosperms is absent in the seeds of
a. Coconut
b. Orchids
c. Maize
d. Castor

Answer:

In orchids, the endosperm is absent, during germination the seeds require nutrients so they enter symbiotic relationships with various fungi that provide them the necessary nutrients for germination.

Hence, the correct answer is option b.

Question 7:

Many pulses of daily use belong to one of the families below (tick the correct answer)
a. Solanaceae
b. Fabaceae
c. Liliaceae
d. Poceae

Answer:

Most of the important pulses belong to this Fabaceae family. These pulses are rich in proteins and are used as food. The common species of pulses are Grain, Pea, and Kidney bean.

Hence, the correct answer is option b.

Question 8:

The placenta is attached to the developing seed near the
a. Testa
b. Hilum
c. Micropyle
d. Chalaza

Answer:

The hilum is a dark spot present behind the micropyle, which is a scar left on the seed coat by the funiculus when it is detached from the fruit wall.

Hence, the correct answer is option b.

Question 9:

Which of the following plants is used to extract the blue dye?
a. Trifolium
b. Indigofera
c. Lupin
d. Cassia

Answer:

Indigofera, is a species of plant from the Fabaceae family. It is one of the original and natural sources of indigo dye.

Hence, the correct answer is option b.

Question 10:

Match the following and choose the correct option

Column I	Column II
A. Aleurone layer	i. without fertilization
B. Parthenocarpic fruit	ii. Nutrition
C. Ovule	iii. Double fertilization
D. Endosperm	iv. Seed

a. A-i, B-ii, C-iii, D-iv
b. A-ii, B-i, C-iv, D-iii
c. A-iv, B-ii, C-i, D-iii
d. A-ii, B-iv, C-i, D-iii

Answer:

Column I	Column II
A. Aleurone layer	ii. nutrition
B. Parthenocarpic fruit	i. without fertilization
C. Ovule	iv. seed
D. Endosperm	iii. double fertilization

Hence, the correct answer is option b.

Question 1:

Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of O₂, root growth is restricted or completely stopped. How do the plants growing in marshlands or swamps obtain their O₂ required for root respiration?

Answer:

The plants growing in marshlands or swamps obtain their O₂ required for root respiration, by growing short, vertical, and negatively geotropic roots called pneumatophores or breathing roots. They bear minute terminal pores called pneumatophores that help in taking atmospheric oxygen.

For example- Rhizophora, Heretiera, Avecennia.

Question 2:

Write floral formula for a flower which, is bisexual; actinomorphic; pentamerous sepal, petal, stamens free with ovary, syncarpous, superior, trilocular with axile placentation.

Answer:

The floral formula of the described flower is represented as:

K₅ C₅A₅ G₍₃₎

The symbols are
Actinomorphic flowers -

Bisexual flower -

Five united Sepals - K₅

Five free petals - C₅

Five free stamens of androecium - A₅

Superior ovary with three syncarpous carpels and axile placentations of gynoecium - G₍₃₎

Question 3:

In Opuntia the stem is modified into a flattened green structure to perform the function of leaves (i.e., photosynthesis). Cite two other examples of modifications of plant parts for the purpose of photosynthesis.

Answer:

In plants like Trapa and Tinospora, root gets modified into photosynthetic chlorophyllous structure.
In Acacia and Parkinsonia, the petiole of the leaf gets modified into flattened,green structure to carry out photosynthesis.

Question 4:

In swampy areas like the Sunderbans in West Bengal, plants bear special kind of roots called _____________.

Answer:

Pneumatophores

Question 5:

In aquatic plants like Pistia and Eichhornia, leaves and roots are found near _____________.

Answer:

the surface of water.

Question 6:

Reticulate and parallel venation are characteristic of _____________ and _____________ respectively.

Answer:

Dicotyledon and monocotyledon

Question 7:

In epigynous flower, ovary is situated below the _____________.

Answer:

In epigynous flower, ovary is situated below the floral whorls like calyx,corolla and androecium, as ovary is inferior.

Question 8:

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

Answer:

C_1+2+(2)A_1+(9),as the corolla of Fabaceae family have five free petals with vexillary aestivation, consisting of a posterior standard, two lateral wings, two anterior ones forming a keel (enclosing stamens and pistil) whereas androecium is ten, diadelphous with dithecous anther.

Question 9:

Name the body part modified for food storage in the following

a. Carrot	__________________________
b. Colocasia	__________________________
c. Sweet potato	__________________________
d. Asparagus	__________________________
e. Radish	__________________________
f. Potato	__________________________
g. Dahlia	__________________________
h. Turmeric	__________________________
i. Gladiolus	__________________________
j. Ginger	__________________________
k. Portulaca	__________________________

Answer:

a. Carrot	Tap root
b. Colocasia	Corm(Stem)
c. Sweet potato	Adventitious root
d. Asparagus	Stem
e. Radish	Tap root
f. Potato	Tuber(Stem)
g. Dahlia	Adventitious root
h. Turmeric	Rhizome(Stem)
i. Gladiolus	Corm(Stem)
j. Ginger	Rhizome(Stem)
k. Portulaca	Adventitious root

Question 1:

Give two examples of roots that develop from different parts of the angiospermic plant other than the radicle.

Answer:

When the root develop from different parts of the angiospermic plant other than the radicle, they are called adventitious roots. The two examples of roots are

Prop root-They are downward growing roots which develop from the nodes of horizontal branches of certain trees. e.g., Ficus bengalensis(Banyan)
Hygroscopic root-The roots which absorb water from the atmosphere with specialized dermal tissue called velamen.They are also called epiphytic root. e.g., Vanda

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?

Answer:

The roots in terrestrial plants help in anchoring the plants to a substrate, absorbing water, dissolving minerals, and storing food but roots of aquatic plants may be absent as in Wolffia. If roots are present they are not well developed, usually, thin adventitious roots are present. Sometimes roots of aquatic plants show modifications and deviations from their normal function. For example- in plants like Trapa, Tinospora the roots are green and highly branched to help in photosynthesis, whereas in plants like Jussiaea, they get inflated so as to help the plant in floating and exchange of gases.

Question 3:

Draw diagrams of a typical monocot and dicot leaves to show their venation pattern.

Answer:

Reticulate venation- The arrangement of veins and veinlets in a leaf in a net like manner as in Dicot.

Parallel venation- The arrangement of veins and veinlets in a leaf in parallel manner as in Monocot.

Question 4:

A typical angiosperm flower consists of four floral parts. Give the names of the floral parts and their arrangements sequentially.

Answer:

An angiosperm flower consists of four floral parts arranged on a flattened peduncle called thalamus or receptacle.These parts are:

Calyx- It is the outermost whorl, which is represented by the sepals and is protective in function.
Corolla- It is the second non-essential attractive whorl, which is represented by the petals and is colourful to attract insects for pollination.
Androecium- It is the third outer essential whorl of the flower which consists of stamen. It releases pollen grains for fertilisation.
Gynoecium- It is the innermost essential whorl of the flower which consists of carpel. It is the female reproductive part of the flower.

Question 5:

Given below are floral formulae of some plants. Draw floral diagrams from these formulae.

Answer:

i)

ii)

iii)

Question 6:

Reticulate venation is found in dicot leaves while in monocot leaves venation is of parallel type. Mention one exception to this generalization.

Answer:

Mostly reticulate venation is shown by the leaves of dicot and parallel venation is shown by leaves of monocot. However, there are certain exceptions where reticulate venation is shown by the leaves of monocot like Smilax and Dioscorea. Similarly, parallel venation is shown by leaves of dicot like Calophyllum and Corymbium.

Question 7:

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

Answer:

Insectivorous plants grow in soil devoid of nitrogen thus they are highly dependent on the insects they consume to satisfy their need of nitrogen even after being photosynthetic (which helps plants to fix atmospheric carbon).

In case of Nepenthes or pitcher plant a large leaf is modified to form a pitcher shaped organ rich in sweet and sticky nector. The sweet and sticky nector produced within the pitcher acts as a powerful attractant for the various insects. Once the insect lands inside the pitcher, the tactile movement of the plant starts and a modified leaf acting as the lid, closes the pitcher. Thus the insect is trapped within the pitcher and is slowly digested from the secretions within the pitcher.

Question 8:

Mango and coconut are ‘drupe’ type of fruits. In mango fleshy mesocarp is edible. What is the edible part of coconut? What does milk of tender coconut represent?

Answer:

Drupe is a type of fruit which has outer thin epicarp, fleshy mesocarp with a stony endocarp.
Coconut is also a drupe like mango. In case of coconut, the edible fleshy part of coconut is cellular endosperm and coconut water is nuclear endosperm.

Question 9:

How can you differentiate between free central and axile placentation?

Answer:

Placentation refers to the arrangement of ovules within the flower ovary. Following are the differences between the free central and axile placentation:

Free Central Placentation	Axile Palcentation
1. The ovary is unilocular	1. The ovary is multilocular
2. Ovules are attached to the free central axis.	2. Ovules are attached to the central axile formed by the radially emerging septa.

Question 10:

Tendrils are found in the following plants. Identify whether they are stem tendrils or leaf tendrils.
a. Cucumber
b. Peas
c. Pumpkins
d. Grapevine
e. Watermelons

Answer:

Tendrils are modified side branches or leaves. They are like tin-coiled structures that loop around support and help the plant's main weak stem to climb up along the support. In the case of cucumber, pumpkins, grapevine, and watermelons tendrils are modified side branches. Where else in the case of peas they are modified leaves.

Question 11:

Why is maize grain usually called as a fruit and not a seed?

Answer:

Maize grain is a type of fruit termed as caryopsis in which, the fruit is dry, one seeded as the ovary contains single ovule and the wall of the ovary is fused with the seed coat. Thus a typical maize grain like many other cereals is a fruit type termed as caryopsis.

Question 12:

Tendrils of grapevines are homologous to the tendril of pumpkins but are analogous to that of pea. Justify the above statement.

Answer:

Tendrils in case of grapevine and pumpkin are modified side stems and thus have the same origin, so they are homologous in nature.
Where else the tendrils of peas are modified leaves as compared to tendrils of pumpkins and grapevines (which are modified side branches). Although the tendrils of peas and grapevine are similar in appearance and function, the two are derived from different plant structures and thus are analogous to each other.

Question 13:

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.

Answer:

Rhizome is a fleshy, swollen, underground stem that stores food. It is distinct from an underground root and in case of ginger it can be identified in the following ways:
i) Nodes and internodes are distinctly visible on the rhizome. Roots do not have nodes and internodes.
ii) Presence of scaly leaves forms the papery outer skin of the rhizome.
iii) Adventitious roots appear from the lower surface of nodes.
iv) It does not perform the function of anchorage and absorption. Rather than it performs in food storage.

Question 14:

Differentiate between
a. Bract and Bracteole
b. Pulvinus and petiole
c. Pedicel and peduncle
d. Spike and spadix
e. Stamen and staminoid
f. Pollen and pollenium

Answer:

Differences between the following:

a) Bracts are small or large leaf like structures subtended generally at the axil of the flower stalk at which the flowers are borne. Where else bracteole are small leafy structures arising at the floral stalk.

b) Pulvinus is a small swelling at the base of the leaf stalk in some cases like that of some leguminous plants. Petiole is the leaf stalk.

c) Flower stalk is termed as pedicel and the stalk of whole floral inflorescence is termed as peduncle.

d) Spike and spadix are both types of racemose infloresence. Spike is a kind of racemose inflorescence which bears sessile flowers on a slender peduncle where else spadix is also a type of spike inflorescence but with a fleshy central axis or peduncle.

e) Stamens are male reproductive organs within the flowers and sterile stamens are termed as staminoids.

f) Pollen is the male gametophyte produced inside the anthers of the stamens and are often dispursed as a mass of coherent pollen grains termed as pollenium.

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.

Answer:

Difference between the gynoecium of members of families Solanaceae, Lillaceae and Fabaceae are following:

Characteristics of Gynoecium	Fabaceae	Solanaceae	Liliaceae
1. Carpel	Monocarpellary	Bicarpellary and syncarpous	Tricarpellary and syncarpous
2. Ovary	Superior and unilocular	Superior and bilocular	Superior and trilocular
3. Placentation	Marginal	Axile	Axile
4. Diagram of gynoecium
5. Floral diagram

Although all of the above mentioned families of plants are of economic importance but let us mention the economic importance of members of family Fabaceae:

i) Many of the members of this family are cultivated as pulses and are a good source of protein for majority of the population.
ii) Indigo, a popular dye also belongs to the same family.
iii) Some crops like sun hemp are grown as fodder crops.
iv) Plants like lupin and sweet pea are often grown as ornamental plants.
v) Some are also grown as herbal medicine like mulethi.

Question 2:

Describe various stem modifications associated with food storage, climbing and protection.

Answer:

Stem modifications in plants associated with food storage are:

i) Rhizome: Rhizome is a prostate, swollen, undergroud stem. It grows horizontally and stores food. It is covered by scaly leaves and has conspicuous nodes visible on it. Example: ginger, turmeric, etc.

ii) Corm: Corm is an undergroud modified, swollen stem. It grows vertically and is quite condensed, with distinct nodes. Example: colocasia, etc.

iii) Tuber: The swollen end of an underground stem is often termed as tuber. Each swollen tuber contains multiple nodes. In case of potato, these nodes are visible as depressions termed as 'eye of the potato'. Each 'eye' acts as a point of origination of a new vegetative propagule.

iv) Bulb: Bulb is a highly condensed, vertical, underground stem. In case of bulb the internodes are so close to each other that they are difficult to distinguish from each other and the whole structures appear as a central disc at the bottom of the bulb. In case of bulbs the leaves emerging at the nodes of these highly condensed internodes are fleshy and stores food. Example: Onion.

Modification of stem for climbing are following:

i) Tendrils: Tendrils are modified axillary buds which have grown to form elongated and coiled structures. These tendrils often wrap themselves around a central support and help the weak plant stem to cling and climb up the support.

Modification of stem for protection are following:

i) Thorns: Thorns are prickly and sharp outgrowths of axillary buds and discourage grazing of the plant body by herbivores.

Question 3:

Stolon, offset and rhizome are different forms of stem modifications. How can these modified forms of stem be distinguished from each other?

Answer:

Difference between the stolon, offset and rhizome are following:

Stolon	Offset	Rhizome
It is an sub-aerial stem modification.	It is an sub-aerial stem modification.	It is an underground stem modification.
It acts as a vegetative propagulae.	It acts as a vegetative propagulae.	It acts as a vegetative propagulae.
It grows over the ground first, before stooping and entering the soil.	It is a characteristic feature of aquatic plants.	It is an undergorund swollen stem meant for storage of food only.
It is several internode long.	It is only one internode long.	It is several internode long.

Question 4:

The mode of arrangements of sepals or petals in a floral bud is known as aestivation. Draw the various types of aestivation possible for a typical pentamerous flower.

Answer:

The main types of aestivation found in a pentamerous flower are valvate, twisted, imbricate, vexillary and quincuncial
When sepals or petals in a whorl just touch one another at the margin, without overlapping, as in Calotropis, it is said to be valvate.
If one margin of the appendage overlaps that of the next one and so on as in china rose, lady’s finger and cotton, it is called twisted.
If the margins of sepals or petals overlap one another but not in any particular direction as in Cassia and gulmohur, the aestivation is called imbricate.
In pea and bean flowers, there are five petals, the largest (standard) overlaps the two lateral petals (wings) which in turn overlap the two smallest anterior petals (keel); this type of aestivation is known as vexillary or papilionaceous.
The type of aestivation in which two petals are completely out and two are completely inside, while one is partially out and partially in is known as quincuncial aestivation. e.g., Cucurbita (Cucurbitaceae).

Question 5:

The arrangements of ovules within the ovary is known as placentation. What does the term placenta refer to? Name and draw various types of placentations in the flower as seen in T.S. or V.S.

Answer:

In terms of botony, placenta is that part of teh ovary wall from the inside, where funiculus of the ovule is attached to the inside part of the ovary wall.

The various types of placentations are-

Marginal placentation-

Axile placentation-

Parietal placentation-

Free central placentation-

Basal placentation-

Question 6:

Sunflower is not a flower. Explain.

Answer:

Sunflower is not a single flower, but rather an inflorescence. It is a type of racemose infloresence termed as head or capitulum.
In case of capitulum, the receptacle end of the peduncle is swollen, fleshy and flat.It bears small sessile florets which are arranged in a centripetal fashion with the youngest ones in the centre and older towards the periphery. In case of sunflower the infloresence is heterogamous as it bears florest of 2 different kinds i.e. ligulate and tubular.
In sunflower, peripheral florets are ligulate and are termed as ray flowers with an overgrown corolla. These ray florets are sterile female florets. The central florets are tubular, disc florets, which are bisexual and reproductive. Thus in case of sunflower the central black region is made up of bisexual, reproductive, disc florets and the bright yellow petals of sunflower are peripheral ray florets with overgrown corolla.

Question 7:

How do you distinguish between hypogeal germination and epigeal germination? What is the role of cotyledon(s) and the endosperm in the
germination of seeds?

Answer:

Difference between hypogeal and epigeal germintion are following:

Hypogeal Germination	Epigeal Germination
1. Cotyledon remain below ground during the process of germination.	1.Cotyledons protrude out of the soil during the process of germination.
2. Epicotyl grows first and elongated during the process of germination.	2. Hypocotyl grows first and elongated during the process of germination.
3. Cotyledon remain non-green and non-photosynthetic.	3. Cotyledon become green and photosynthetic during the growth of the plantlet.
4. Example: Bean, Castor, etc.	4.Example: Rice, maize, etc.

Role of cotyledon(s) during the process of germination of seeds is following:

Cotyledon and endosperm serve as a food reservoir for the growing embryo. The food is digested by various enzymes and become available during germination which provides energy to the plantlet. Once new leaves start to emerge on the plant it begins photosynthesis and produces its own food. Till then these two structures act as food reservoirs.

Question 8:

Seeds of some plants germinate immediately after shedding from the plants while in other plants they require a period of rest before germination. The later phenomena is called as dormancy. Give the reasons for seed dormancy and some methods to break it.

Answer:

Dormancy period of seeds of various plants vary and is dependent on many internal and external factors. Some of the internal factors that dictate the period of seed dormancy are:
i) Internal genetics of the plant.
ii) Its hard seed coat.
iii) Increased level of abscisic acid (ABA).
iv) Low levels of gibberellins within the seed.
iv) Impearable layers of seed coat preventing entry of moisture and air deep within the seed.
v) In some plants seeds are shed with the immature embryo, thus the seeds remain dormant to allow embryo growth, delaying germination.

Many effective ways are there to help seeds overome dormancy. Some of them are as following:
i) Place the seeds in suitable environment with adequate moisture, temperature and oxygen to promote its faster germination.
ii) Application of phytohormones like gibberellins are also one of the ways to break seed dormancy and promote germination.
iii) Various methods to wear down the tough seed coat are also applied to promote seed germination. They are often termed as scarification.

NCERT Solutions for Class 11 Science Biology Chapter 5 - Morphology Of Flowering Plants

Page No 21:

Question 1:

Answer:

Page No 21:

Question 2:

Answer:

Page No 21:

Question 3:

Answer:

Page No 22:

Question 4:

Answer:

Page No 22:

Question 5:

Answer:

Page No 22:

Question 6:

Answer:

Page No 22:

Question 7:

Answer:

Page No 22:

Question 8:

Answer:

Page No 22:

Question 9:

Answer:

Page No 23:

Question 10:

Answer:

Page No 23:

Question 1:

Answer:

Page No 23:

Question 2:

Answer:

Page No 23:

Question 3:

Answer:

Page No 23:

Question 4:

Answer:

Page No 23:

Question 5:

Answer:

Page No 23:

Question 6:

Answer:

Page No 23:

Question 7:

Answer:

Page No 23:

Question 8:

Answer:

Page No 23:

Question 9:

Answer:

Page No 24:

Question 1:

Answer:

Page No 24:

Question 2:

Answer:

Page No 24:

Question 3:

Answer:

Page No 24:

Question 4:

Answer:

Page No 24:

Question 5:

Answer:

Page No 24:

Question 6:

Answer:

Page No 24:

Question 7:

Answer:

Page No 25: