MCQ ON MODIFIED STEM / MODIFIED STEM class 11 for NEET

MCQ ON MODIFIED STEM / MODIFIED STEM class 11 for NEET | MODIFIED STEM class 11| MCQ MODIFIED STEM with Answer | Check the below NCERT MCQ question for class 11Biology based on the with Answers.

MCQ on MODIFIED STEM class 11Biology with answers were prepared based on the latest pattern. We have provided class 11 Biology MCQs question with Answers to help students understand the concept very well.

MCQ ON MODIFIED STEM / MODIFIED STEM class 11 for NEET

MCQ ON MODIFIED STEM is useful for NEET / CSIR / UGC / CBSE / ICSE / AIIMS / EXAM / AFMC EXAM / STATE LEVEL MEDICAL EXAM/ KVS PGT BIOLOGY / NVS PGT BIOLOGY EXAM 2023-2024 ,2025

INTRODUCTION:-
MODIFIED STEM:-
The stem may not always be typically like what they are expected to be.
They are modified to perform different functions.
Underground stems of potato , ginger , turmeric , zamikand , colocasia are modified to store food in them.

They also act as an organs of perennetation to tide over conditions unfavourable for growth.

Stems tendris which develop from axillary buds , are slender and spirally coiled and helps plants to climb such as in gourds ( cucumber , pumpkins , watermelon ) and grapevines .

Axillary buds of stems may also get modified in many plants such as citrus , Bougainvillea .

They protect plant from browsing animals.Some plants of arid regions modified their stems into flattened (opuntia) or fleshy cylindrical ( euphorbia) structures.

They contain chlorophyll and carry out photosynthesis.

Underground stems of some plants such as grass and strawberry etc spread to new niches and when older parts die new plants are formed.

PHYLLOTAXY:-
phyllotaxy is the pattern of arrangement of leaves on the stem or branch. This is usually of three types – alternate phyllotaxy , opposite phyllotaxy and whorled phyllotaxy.

Alternate phyllotaxy:- In alternate phyllotaxy type of phyllotaxy a single leaf arises at each node in alternate manner as in China rose, Mustard and sunflower plants.

Opposite phyllotaxy:- In opposite phyllotaxy a pair of leaves arise at the each node and lie opposite to each other as in calotropis and guava plants.

Whorled phyllotaxy:-
If more than two leaves arise at each node and a form a whole , it is called whorled as in Alstonia

CALYX:-
Calyx is the outermost whorl of the flower and the members are called sepals.

Generally , sepals are green , leaf – like and protect the flower in the bud stage.The calyx may be gamopetalous sepals united or polysepalous sepals free.

COROLLA:-
Corolla is composed of petals.Petals are usually brightly coloured to attract insects for pollination. Like calyx corolla may be also united gamosepalous petals united or polysepalous petals free.

The shape and colour of Corolla vary greatly in plants.
Corolla may be tubular , bell-shaped , funnel – shaped or wheel – shaped.

GYNOECIUM :-
Gynosium is the female reproductive part of the flower and is made of one more carpels.
A carpel consist of three parts namely stigma style and ovary.

Ovary is the enlarged basal part , on which lies the elongated tube, the style .

The style connects the ovary to the stigma.

Stigma is the usually tip of the style and is the receptive surface for pollen grains .

Each ovary bears one or more ovules attached to a flattened, cushion like placenta.

When more than one carpel is present , there may be free as in Lotus and rose and are called Apocarpous.

They are termed as Syncarpous when carpels are fused as in mustard and tomato.

After fertilisation , the ovules develop into seeds and the ovary matures into a fruit.

Androecium is composed of stamens.Each stamens which represents the male reproductive organ consists of a stalk or a filament and an anther.

Each anther is usually bilobed and each lobe has two chambers , the pollen sacs. The pollen grains are produced in pollen-sacs.A sterile stamen is staminode .

Stamens of flower may be united with other members such as petals or among themselves .

When stamens are attached to the petals , they are epipetalous as in brinjal

Epiphyllous when attached to the perianth as in the flower of Lily.
The stamens in a flower may either remain free ( polyandrous) or may be united in varying degrees .

The stamens may be united into bunch or one bundle ( monoadelphous) as in China rose or two bundles (diadelphous) as in pea , or into more than two bundles (polydelphous) as in citrus.

There may be variations in the length of filaments within a flower as in salvia and mustard.

MCQ ON MODIFIED STEM class 11 for NEET/KVS PGT BIOLOGY / NVS PGT BIOLOGY EXAM 2023-2024,2025

1. Stem tendrils which develop from

(a) terminal buds
(b) axillary buds
(c) apical buds
(d) all the above

Ans (b) axillary buds

2. Gourds cucumber, pumpkins , watermelon have modified stem

(a) thorns
(b) tendrils
(c) phyllotaxy
(d) sepals

Ans. (b) tendrils

3.Axillary buds of stems may also get modified into woody straight and pointed is

(a) tendrils
(b) apical buds
(c) whorled phyllotaxy
(d) thorns

Ans. (d) thorns

4.Thorns found in

(a) citrus
(b) Bougainvillea
(c) both a and b
(d) colocasia

Ans.(c) both a and b

5. Which protects plants from browsing animals ?

(a) thorns
(b) tendrils
(c) axillary buds
(d) all the above

Ans.(a) thorns

6. Some plants of arid regions modify their stem into flattened in

(a) zamikand
(b) colocasia
(c) opuntia
(d) all the above

Ans.(c) opuntia

7. Stem modified into fleshy cylindrical structures

(a) Euphorbia
(b) maize
(c) pea
(d) cactus

Ans.(a) Euphorbia

8. Underground stems of some plants ………. spread to new niches and when older parts die new plants are formed.

(a) grass
(b) strawberry
(c) both a and b
(d) jasmine

Ans.(c) both a and b

9. In plants like …………. A slender lateral branch arises from the base of the main axis and after growing aerially for some time arch downward to touch the ground.

(a) mint
(b) jasmine
(c) both a and b
(d) sugarcane

Ans. (c) both a and b

10. A lateral branch of with short internode and each node bearing a rosette of leaves and a tuft of roots is found in aquatic plants like

(a) pistia
(b) eichhornia
(c) both a and b
(d) pineapple

Ans. (c) both a and b

11.The main function of stem is

(a) conducts water
(b) storage of food
(c) vegetative propagation
(d) all the above

Ans.(d) all the above

12. The lateral branches originate from the basal and underground portion of the main stem grow horizontally beneath the soil and then come our obliquely upward giving rise to leafy shoot.

a) banana
b) pineapple
c) Chrysanthemum
(d) all the above

Ans . (d) All the above

13. Underground stems of ………….are modified to store food in them

(a) potato
(b) ginger
(c) turmeric
(d) all the above

Ans.(d) all the above

14. In citrus and Bougainville found

(a) tendrils
(b) thorns
(c) a triple leaf
(d) all the above

Ans. (b ) thorns

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