Important Questions for Class 11 Biology 15th Chapter Plant Growth and Development MCQ, Very Short, Short Type, Long Type
CBSE Class 11 Important Questions for Class 11 Biology Chapter 15 Plant Growth and Development all MCQ Type, Very Short Type, Assertion Reason Type, Case Study, Short Type and Long Type Questions with Answers by Expert. Important Questions for Section A, B, C, D Class 11 Biology Chapter 15.
- MCQs
Q.1) The equation “Lt = L0 + rt” represents which growth?
a.) arithmetic growth
b.) geometric growth
c.) absolute growth
d.) relative growth
Q.2) Auxin was isolated by_______
a.) Charles Darwin
b.) F.W. Went
c.) Francis Darwin
d.) E. Kurosawa
Q.3) Example of gaseous PGR is
a.) Auxin
b.) Gibberellin
c.) Ethylene
d.) Abscisic acid
Q.4) Assertion: A sigmoid curve is obtained when total growth is plotted against time.
Reason: Growth is slow in the lag phase, rapid during logphase, slow in stationary phase.
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) if both assertion and reason are false.
Q.5) Assertion: Auxin is used as herbicide
Reason: Auxin is used to kill monocotyledonousweeds, does not affect mature dicotyledonous plants.
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) if both assertion and reason are false.
Q.6) Assertion: In many plants there is no such correlation between exposure to light duration and induction of flowering response.
Reason: Some plants plants require the exposure to light for a period exceeding a well-defined critical duration.
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) if both assertion and reason are false.
Q.7) Seedless fruit formation is
a.) parthenogenesis
b.) parthenocarpy
c.) budding
d.) bolting
Q.8) Which growth hormone promotes bolting?
(a) Auxins
(b) Gibberellins
(c) Ethylene
(d) Cytokinin
Q.9) Which phytoharmone is the derivative of Methionine?
(a) Auxin
(b) Gibberelic acid
(c) Cytokinin
(d) Ethylene
Q.10) Assertion: foolish seedlingdisease of rice seedlings was reported by E. Kurosawa
Reason: it is due to the ability of gibberellins to cause an increasein length of axis
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) if both assertion and reason are false.
- Answer in one sentence
Q.1) What is critical period?
Ans. Flowering is not induced in some plants unless they are exposed to light for a period longer than or shorter than a well-defined critical duration. This is called critical period.
Q.2) State the parameters used to measure growth.
Ans. Growth is measured using a variety of criteria such as fresh weight, dry weight, length, area, volume, and cell number.
Q.3) What are the three phases of growth?
Ans. The 3 phases of growth are meristematic phase, elongation phase and maturation phase.
Q.4) State the reasons for seed dormancy
Ans. Seed dormancy is caused by an impermeable and hard seed coat, the presence of chemical inhibitors such as abscissic acids, phenolic acids, and para-ascorbic acid, and underdeveloped embryos.
Q.5) State the functions of Kinetin.
Ans. kinetin promotes cell division by helping in the production of new leaves, chloroplasts in leaves, lateral shoot growth, and the formation of accidental shoots. Cytokinins aid in the reversal of apical dominance. They aid to prolong leaf senescence by promoting nutrient mobilisation.
Q.6) Why does decapitation result in formation of lateral buds?
Ans. Apical dominance occurs when the developing apical bud restricts the growth of the lateral (axillary) buds in most higher plants due to auxin production in apical. Hence Decapitation frequently results in the formation of lateral buds as auxin is no longer present.
Q.7) What is respiratory climactic?
Ans. The PGR Ethylene increases the rate of respiration when the fruits are maturing. The term “respiratory climactic” refers to this increase in breathing rate.
Q.8) Give examples of extrinsic factors affecting plant growth.
Ans. Plant growth and development are influenced by many extrinsic variables such as temperature and light. Vernalization, flowering, dormancy, seed germination, plant motions, and so on are examples of such events.
- Answer in short
Q.1) Explain plasticity with a suitable example.
Ans. 1.) Plants generate a number of different structures by following distinct paths in response to their environment or life stages.
2.) Plasticity is a term used to describe this characteristic, which can be seen in plants like cotton, coriander, and larkspur.
3.) Plasticity can be seen in the phenomena of heterophylly.
4.) The leaves of the juvenile plant are distinct in shape from those of the adult plant in such plants.
5.) The variation in shape of leaves produced in air against those produced in water in buttercup, on the other hand, represents heterophyllous development as a result of the environment.
Q.2) State any 5 functions of ethylene.
Ans. 1.) In dicot seedlings, ethylene stimulates horizontal development of seedlings, axis swelling, and apical hook formation.
2.) Ethylene causes plant organ senescence and abscission, particularly in leaves and flowers.
3.) Ethylene is an excellent ripening agent.
4.) Ethylene causes seed and bud dormancy to be broken, as well as the germination of peanut seeds and the sprouting of potato tubers.
5.) In deep water rice plants, ethylene stimulates rapid internode/petiole elongation.
Q.3) What are necessary conditions for growth in plants?
Ans. 1.) Water, oxygen, and nutrients are all necessary for growth. Plant cells expand in size as a result of cell enlargement, which necessitates the use of water.
2.) Turgidity of cells aids in cell growth extension. As a result, plant growth and development are inextricably tied to the plant’s water state.
3.) Water also serves as a medium for the enzymatic activities that are necessary for growth.
4.) Oxygen aids in the release of metabolic energy required for growth.
6.) Plants require macro and micro nutrients necessary elements for protoplasm formation and as a source of energy.
7.) Furthermore, each plant organism has a preferred temperature range for optimal growth.
8.) Any departure from this range could jeopardize the species’ survival.
9.) Certain phases/stages of growth are also affected by environmental cues such as light and gravity.
- Answer in brief
Q.1) Plant growth is unique. Justify
Ans. 1.) Plants have the ability to grow indefinitely during their lives.
2.) The presence of meristems at specific sites throughout the plant’s body gives it this power.
3.) These meristems’ cells have the ability to divide and self-perpetuate.
4.) The product, on the other hand, quickly loses its ability to divide, and the plant body is made up of these cells.
5.) The open form of growth is defined as a type of growth in which new cells are constantly added to the plant body as a result of the meristem’s activity.
Q.2) What are the methods to break food dormancy?
Ans. Seed dormancy is an event when seed is unable to germinate.
- Seed dormancy can be broken by natural and man-made methods.
- Mechanical abrasions using knives, sandpaper, or strong shaking, for example, can break the seed coat barrier in some seeds.
- Microbial activities and passage through the digestive tract of animals create these abrasions in nature.
- The effect of inhibitory compounds can be reduced by freezing the seeds or using chemicals like gibberellic acid and nitrates.
- Seed dormancy can also be overcome by altering environmental variables like as light and temperature.
Q.3) Explain the two different types of Plant growth promoters.
Ans. 1.) PGPRs are divided in 2 groups according to their activity
2.) Group 1: One group of PGRs are involved in growth promoting activities, such as cell division, cell enlargement, pattern formation, tropic growth, flowering, fruiting and seed formation.
3.) These are also called plant growth promoters, e.g., auxins, gibberellins and cytokinins.
4.) Group 2: The PGRs of the other group play an important role in plant responses to wounds and stresses of biotic and abiotic origin.
5.) They are also involved in various growth inhibiting activities such as dormancy and abscission.
6.) The PGR abscisic acid belongs to this group.
7.) The gaseous PGR, ethylene, could fit either of the groups, but it is largely an inhibitor of growth activities.