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Q.1
Food is preserved at low temperature because ... ... [ MPPMT 1998]
0%
a) Bacterial attack is minimised
0%
b) For easy cooking
0%
c) For easy digestion
0%
d) All the above
Explanation
Foods are stored at low temperatures to prevent the growth of microorganisms, activity of enzymes, and purely chemical reactions. Freezing prevents the growth of most foodborne microorganisms and refrigeration temperatures slow down the growth of microorganisms. Answer : (a)
Q.2
Movement of sperms towards archegonial necks due to component of their exudate is ... ... [ RPMT 1998]
0%
a) Chemotropism
0%
b) Chemotaxis
0%
c) Phototaxis
0%
d) Hydrotropism
Explanation
Chemotaxis is movement of a motile cell or organism, or part of one, in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance. Another-ozoids simply oozes into the area around the antheridium and further dispersal is by gradient of increasing or decreasing concentration Answer : (b)
Q.3
Match the columns ... ...[ kerala 2006]
a) Phototaxis
Circular movement of protoplasm in response to warm condition
b) Thermotaxis
Upward movement of floral organs
c) Chemotaxis
Drooping of leaf
d) Hyponasty
Movement of another-ozoids towards archegonia
e) Seismonasty
Movement of
Chlamydomonas
0%
a) a - 5, b - 4, c - 3, d - 2, e - 1
0%
b) a - 5, b - 1, c - 4, d - 2, e - 3
0%
c) a - 4, b - 5, c- 1, d- 2, e- 3
0%
d) a - 2, b- 3, c- 4, d- 5, e- 1
Explanation
Phototaxis is an organism's movement in response to light. A Chlamydomonas cell perceives light at its eyespot, the photoreceptive organelle observed as an orange spot located near the cell equator. a - 5, Thermotaxis is a behavior in which an organism directs its locomotion up or down a gradient of temperature. b - 1, Chemotaxis is movement of a motile cell or organism, or part of one, in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance. another-ozoids simply oozes into the area around the antheridium and further dispersal is by gradient of increasing or decreasing concentration c - 4, Hyponasty an upward bending of leaves or floral organs, caused by increased growth on their lower surface. d - 2, Seismonasty is a nastic movement. When any organ of Mimosa pudica is touched, the stimulus reaches the base of the leaf. Owing to this stimulus, the turgor of lower half of pulvinus is lost and the leaf droops down. e - 3 Answer: (b)
Q.4
The regulator which retards ageing/senescence of plant parts is ... ... [ AFMC 2010]
0%
a) Cytokinin
0%
b) Auxin
0%
c) Gibberellin
0%
d) Abscisic acid
Explanation
Cytokinins modulate a number of important developmental processes, including the last phase of leaf development, known as senescence, which is associated with chlorophyll breakdown, photosynthetic apparatus disintegration and oxidative damage. . Answer : (a)
Q.5
Phytochromes are ... ... [ CBSE 1990]
0%
a) Chemicals regulating flowering
0%
b) Chemicals regulating secondary growth
0%
c) Hormones regulating growth from seed to adulthood
0%
d) Regulators synthesised by plants and influencing physiological process
Explanation
Phytochrome regulates the expression of nuclear genes. Phytochrome plays a central role in the synthesis of RUBISCO, the chlorophyll a/b-binding protein, and many other chloroplast proteins. Answer : (d)
Q.6
Tropic movement is due to ... ... [ CPMT 1998]
0%
a) Cell elongation
0%
b) Cell division
0%
c) Both a and b
0%
d) Cell thickening
Explanation
A tropism is a growth movement whose direction is determined by the direction from which the stimulus strikes the plant. High auxin concentrations promote cell elongation and hnce the growth Answer : (a)
Q.7
Physiologically active form of phytochrome is ... ... [ CPMT 2004]
0%
a) P730/Pfr
0%
b) P660/Pr
0%
c) P700
0%
d) P680
Explanation
Pfr (P730) is the physiologically-active form of the protein; exposure to red light (~730 nm) yields physiological activity in the plant. Exposure to far-red light converts the Pfr to the inactive Pr form, inhibiting phytochrome activity. Answer : (a)
Q.8
Falling of floral parts, leaves and fruits from the mother plant is called ... .... [ JKCMEE 2010]
0%
a) Senescence
0%
b) Abscission
0%
c) Photoperiodism
0%
d) Vernalisation
Explanation
Abscission is the natural detachment of parts of a plant, typically dead leaves and ripe fruit. Senescence loss of a cell's power of division and growth. Photoperiodism the response of an organism to seasonal changes in day length. Vernalisation the cooling of seed during germination in order to accelerate flowering when it is planted. Answer : (b)
Q.9
Bending of stem/coleoptile towards light or shoot of potted plant placed near a window is due to .... ... [ MPPMT 1990]
0%
a) Greater oxygen availability to the tip
0%
b) More auxin content on the shaded side
0%
c) Greater light availability to tip
0%
d) Availability of necessary warmth to tip
Explanation
The higher concentration of auxin on the shady side causes the plant cells on that side to grow more so it bends toward the light. This bending toward light is called phototropism. Answer : (b)
Q.10
Phytochrome was isolated by ... ..... [ MPPMT 2002]
0%
a) Butler et al
0%
b) W. Went
0%
c) R. Hill
0%
d) Borthwick et al
Explanation
The phytochrome pigment was discovered by Sterling Hendricks and Harry Borthwick at the USDA-ARS Beltsville Agricultural Research Center Answer : (d)
Q.11
Pruning of plants promotes branching due to sensitization of axillary budes by ... ... [ AIIMS 2004]
0%
a) IAA
0%
b) Ethylene
0%
c) Gibberellin
0%
d) Cytokinin
Explanation
IAA is the main auxin in plants, regulating growth and developmental processes such as cell division and elongation, tissue differentiation, apical dominance, and responses to light, gravity, and pathogens. Answer : (a)
Q.12
Closure of lid in Pitcher Plant is a ... ... [ CBSE 1995]
0%
a) Tropic movement
0%
b) Turgor movement
0%
c) Paratonic movement
0%
d) Autonomic movement
Explanation
Nepenthes (pitcher plant) is an insectivorous plant. In this the leaf lamina is modified to form a pitcher and leaf apex forms a coloured lid. When the insect enter the pitcher it is an external stimuli, so the closure of the lid is paratonic movement. Paratonic movements also of three kinds:- Tropic movements Tactic movements Nastic movements Answer : (c)
Q.13
Flowering of Chrysanthemum is inhibited by ... ... [ MPPMT 2002]
0%
a) IAA
0%
b) GA3
0%
c) Cytokinin
0%
d) Ethylene
Explanation
During bud development in citrus, the application of GA3 has shown to inhibit flower production, leading to greater ratio of terminal flowers in the leafy shoots thus higher development of fruits Answer : (b)
Q.14
Hormone that promotes growth of lateral buds/has negative effect on apical dominance is .... .... [ AIIMS 2000 ]
0%
a) Cytokinin
0%
b) Gibberellin
0%
c) Auxin
0%
d) Both b and c
Explanation
Cytokinin production slows down the process of senescence. However, accumulation of sugars during senescence, due to the breakdown of accumulated starch or the preferential export of N2 from the leaf, can block the effect of cytokinin, especially in low light. Answer : (a)
Q.15
Which movement occurs due to external stimulus? ... .. [ CPMT 1998]
0%
a) Tropic
0%
b) Nastic
0%
c) Tactic
0%
d) All the above
Explanation
Tropic movement is the movement of the plant in response to the stimulus present in the environment. Nastic movements are plant movements that occur in response to environmental stimuli but unlike tropic movements, the direction of the response is not dependent on the direction of the stimulus. Tactic movement is a type of movement in plants which is directed towards (positive) or away from (negative) a stimulus. Answer : (d)
Q.16
Growth regulator ethylene is used for ... .... [ BHU 2000 ]
0%
a) Retarding ripening of tomatoes
0%
b) Speeding up ripening of fruits
0%
c) Slowing down ripening of apples
0%
d) Both b and c
Explanation
Growth regulator ethylene is used for speeding up ripening of fruits Answer : (b)
Q.17
Gibberellins bring about .... ... [ MPPMT 1999 ]
0%
a) Yellowing of leaves
0%
b) Promotion of rooting
0%
c) Elongation of genetically dwarf plants
0%
d) Dwarfing of genetically tall plant
Explanation
Gibberellins are growth promoting phytohormones. Gibberellins promote stem elongation in many plants. When gibberellin is applied to a plant, particularly certain dwarf varieties, this elongation may be spectacular. These varieties put less of their resources into stem height and more resources into grain production. Answer : (c)
Q.18
Abscisic acid is called stress hormones as it ... .... [ AIIMS 2012]
0%
a) Induces flowering
0%
b) Breaks seed dormancy
0%
c) Promotes leaf fall
0%
d) Promotes stomatal closure
Explanation
Abscisic acid (ABA) is a plant hormone involved in the response of plants to reduced water availability. Reduction of guard cell turgor by ABA diminishes the aperture of the stomatal pore and thereby contributes to the ability of the plant to conserve water during periods of drought. Answer : (d)
Q.19
Shock movements of leaves of Sensitive Plant, Mimosa pudica, are ... ... [ BHU 1997]
0%
a) Thermonasty
0%
b) Seismonasty
0%
c) Hydrotropism
0%
d) Chemonasty
Explanation
Thigmonasty or seismonasty is the nastic response of a plant or fungus to touch or vibration. Conspicuous examples of thigmonasty include many species in the leguminous subfamily Mimosoideae, active carnivorous plants such as Dionaea and a wide range of pollination mechanisms. Answer : (b)
Q.20
Which one can absorb red and far-red light? ... ... [ BHU 1998]
0%
a) Carotene
0%
b) Xanthophyll
0%
c) Chlorophyll
0%
d) Phytochrome
Explanation
Pfr absorbs far-red light (~730 nm) and is quickly converted back to Pr. Pfr is the physiologically-active form of the protein; exposure to red light yields physiological activity in the plant. Answer : (d)
Q.21
The hormone which promotes flowering in long day conditions and controls sex expression is ... ... [ BHU 2001]
0%
a) Auxin
0%
b) Cytokinins
0%
c) Gibberellins
0%
d) Ethylene
Explanation
Gibberellins (GAs) to promote bolting and flower formation in long-day (LD) and biennial plants under conditions that would not normally permit flowering contributed to the realization that these compounds may function as endogenous growth regulators Gibberellin showed significant effects in promoting maleness in monoecious genotypes and increasing male inflorescences in male plants. Answer : (c)
Q.22
Antherozoids are attracted towards archegonia in a fern plant. The phenomenon is ... ... [ CMC 2003]
0%
a) Nyctinasty
0%
b) Chemonasty
0%
c) Thigmonasty
0%
d) Seismonasty
Explanation
Chemonasty is the nastic movement of a plant in response to a chemical stimulus. The antherozoids are chemotactically attracted towards archegonia. Answer : (b)
Q.23
In root, the region of fastest growth is ... ... [ AFMC 1993]
0%
a) Root hair zone
0%
b) Behind the root tip
0%
c) Root tip
0%
d) Before the root tip
Explanation
The growing part of a root tip is divided into four regions: 1. Root cap – A cap of cells that protects the apical meristem behind it from abrasion and damage as the root tip grows through the soil. 2. Region of cell division - The growing point (meristem) a region of rapid mitosis, which produces the new cells for root growth. 3. Region of elongation: The zone where cells increase and elongate in size in the direction of the axis of the root. It is at this time that they are sensitive to gravity and respond with gravitropism. 4. Region of maturation (or differentiation): the zone where develop the differentiated tissues of the root. Here are located the root hairs which greatly increase the surface area available for the uptake of water from the soil. Answer : (b)
Q.24
Ethylene is connected with ... ...[ DPMT 2001]
0%
a) Aerobic respiration
0%
b) Climacteric respiration
0%
c) Anaerobic respiration
0%
d) Fermentation
Explanation
The climacteric is a stage of fruit ripening associated with increased ethylene production and a rise in cellular respiration Answer : (b)
Q.25
Hormone responsible for plant and seed dormancy during drought is ... ... [ AIIMS 2002]
0%
a) IBA
0%
b) NAA
0%
c) ABA
0%
d) Zeatin
Explanation
Embryonic ABA plays a central role in induction and maintenance of seed dormancy and also inhibits the transition from embryonic to germination growth. Answer : (c)
Q.26
When the dark period of short day plants is interrupted by a brief exposure of light the plants? .... ... [ PMT 2003]
0%
a) Will not flower at all
0%
b) Flowers immediately
0%
c) Gives more flowers
0%
d) Turns into a long day plant
Explanation
Short-day plants are those plants that flower when they are exposed to long periods of darkness and short periods of light. Dark period of short day plants is interrupted by a brief exposure of light the plants then it will not flower at all. Answer : (a)
Q.27
Opening of flowers involves ... ... [ CPMT 2002]
0%
a) Epinasty
0%
b) Hyponasty
0%
c) Nutation
0%
d) Phototaxis
Explanation
Epinasty is a nastic movement in which a plant part, such as a flower petal is bent outward and often downward. Answer : (a)
Q.28
Tendrils exhibit/twining of tendrils is due to ... .. [ AIIMS 2000 ]
0%
a) Thigmotropism
0%
b) Seismonasty
0%
c) Heliotropism
0%
d) Diageotropism
Explanation
Thigmotropism the turning or bending of a plant or other organism in response to a touch stimulus. Thigmotropism is typically found in twining plants and tendrils. Answer : (a)
Q.29
Food products are kept in cold storage or refrigerator in order to ... ... [ MPPMT 1997]
0%
a) Make them tasty
0%
b) Use in off-season
0%
c) Maintenance of freshness, longevity and taste due to low respiration
0%
d) Keep them cool
Explanation
The moisture-control available in many refrigerators also helps slow the deterioration of foods, so that two of the three favorable situations for microorganism growth are eliminated. Microorganisms released relatively low CO2 at low temperatures. Answer : (c)
Q.30
Light inhibits seed germination of ... ... [ EAMCET 2002]
0%
a) Lactuca
0%
b)Capsella
0%
c) Allium
0%
d) Tobacco
Explanation
Most seeds germinate best under dark conditions and might even be inhibited by light e.g., Phacelia and Allium spp. Answer : (c)
Q.31
Which combination is used in fruit ripening? ... ...[ CBSE 1998]
0%
a) 80% C2H4 + 20% O2
0%
b) 80% C2H4 + 20% CO2
0%
c) 80%CO2 + 20% C2H4
0%
d) 80% CH4 + 20% CO2
Explanation
Ethylene production is inhibited at low O2 concentrations; the receptor has an O2 affinity closely similar to that of cytochrome oxidase Answer : (a)
Q.32
What is correct? ... ..... [ CET Chd 2002]
0%
a) Albinism is genetic and etiolation is physiological
0%
b) Etiolation is genetic and albinism is physiological
0%
c) Etiolation is irreversible
0%
d) Etiolation and albinism are synonyms
Explanation
Albinism is defined as a plant's inability to produce chloroplasts and thus carry out the process of photosynthesis. Etiolation is a physiological enomenon shown by green plants when kept in dark. Answer : (a)
Q.33
Avena coleoptile auxin is ... ... [ JIPMER 2002]
0%
a) IBA
0%
b) Indole 3-lactic acid
0%
c) Indole 2-acetic acid
0%
d) Indole 3-acetic acid
Explanation
Indole-3-acetic acid (IAA, 3-IAA) is the most common naturally occurring plant hormone of the auxin class. Answer : (d)
Q.34
Bolting does not require ... .... [ kerala 2000 ]
0%
a) Short days
0%
b) Long days
0%
c) Internode elongation in rosette plants
0%
d) Cold nights
Explanation
Rapid growth of the dwarf stem called "bolting" Cold nights, hot days and late frosts may also contribute to premature initiation of flowering. under long days in the spring and flowers are formed on the elongated stem. Answer : (a)
Q.35
Bending of shoot tip in the absence of light is .... .... [ Har PMT 2001]
0%
a) Chlorosis
0%
b) Emasculation
0%
c) Etiolation
0%
d) Tanning
Explanation
Etiolation is a process in flowering plants grown in partial or complete absence of light. It is characterized by long, weak stems; smaller leaves due to longer internodes; and a pale yellow color Etiolation in plants is a natural phenomenon and is simply a plant’s way of reaching for a light source. Which causes bending of shoot tip Read more at Gardening Know How: What Is Etiolation: Learn About Etiolation Plant Problems https://www.gardeningknowhow.com/garden-how-to/info/what-is-etiolation.htm Chlorosis is loss of the normal green coloration of leaves of plants, caused by iron deficiency in lime-rich soils, disease, or lack of light Removal of stamens or anthers or killing the pollen of a flower without the female reproductive organ is known as emasculation. Tanning - process in which skin pigmentation darkens as a result of exposure to ultraviolet light. Answer : (c)
Q.36
Which of the following physiological effects in caused in plants by gibberellic acid? ... ... [ AFMC 1997]
0%
a) Shortening of genetically tall plants
0%
b) Elongation of genetically dwarf plants
0%
c) Rooting in stem cuttings
0%
d) Yellowing of young leaves
Explanation
Gibberellins cause cell elongation of intact plants in general and increased internodal length of genetically dwarfed plants. Answer : (b)
Q.37
Which one is not a physiological effect of auxin ... ...[ kerala 2012]
0%
a) Promotes bolting
0%
b) Prevents early fruit and leaf drop
0%
c) Promotes flowering
0%
d) Initiates rooting in stem cuttings
Explanation
Bolting is induced by plant hormones of the gibberellin family Physiological effects of Auxin are 1. Cell elongation 2. Apical dominance 3. Root initiation 4. Prevention of Abscission 5. Parthenocarpy 6. Respiration 7. Callus formation 8. Vascular differentiation Answer : (a)
Q.38
Movements of tentacles in Drosera are ... .... [ Guj CET 2009]
0%
a) Photonastic
0%
b) Thermonastic
0%
c) Thigmonastic
0%
d) Seismonastic
Explanation
Drosera, commonly known as the sundews. These members of the family Droseraceae lure, capture, and digest insects using stalked mucilaginous glands covering their leaf surfaces. Drosera able to move their tentacles in response to contact with edible prey Thigmonasty or seismonasty is the nastic response of a plant or fungus to touch or vibration. Answer : (c)
Q.39
Which one is a short day plant? ... ... [ CPMT 1995]
0%
a) Brassica campestris
0%
b) Raphanus sativus
0%
c) Glycine max
0%
d) Papaver somniferum
Explanation
Answer : (c)
Q.40
Growth hormone obtained from a fungus is .... ... [ BHU 2007]
0%
a) Cytokinin
0%
b) Gibberellin
0%
c) Auxin
0%
d) Phytokinin
Explanation
Gibberellin, the name is derived from Gibberella fujikuroi, a hormone-producing fungus in the phylum Ascomycota that causes excessive growth and poor yield in rice plants Answer : (b)
Q.41
Oat - coleoptile test (coleoptile-test) is conducted for which hormone ?
0%
a) Indole acetic acid (IAA)
0%
b) Indole naphthalne acetic acid (INAA)
0%
c) Abscisic acid
0%
d) Gibberrelic acid (GA)
Explanation
Answer:(a)
Q.42
Which one does not affect apical dominance? ... ... [ MPPMT 2001]
0%
a) IAA
0%
b) IBA
0%
c) Gibberellins
0%
d) Indole Acetaldehyde
Explanation
Apical dominance occurs when the shoot apex inhibits the growth of lateral buds so that the plant may grow vertically Gibberellin reduced the number of elongating buds and promoted growth of the first or second uppermost axillary bud, thus restoring apical dominance. It is concluded that gibberellin participates in the expression of apical dominance. That is it work against Apical dominance Answer : (c)
Q.43
Sensation of phototropism is perceived by ... .. [ CPMT 1994]
0%
a) Root tip
0%
b) Shoot tip
0%
c) Axillary bud
0%
d) Node
Explanation
The shoot tip is sensitive to light and produces auxin – if the tip is covered phototropism doesn't occur. Answer : (b)
Q.44
Effect of daily light period on flowering is ... ... [ CPMT 1999]
0%
a) Photorespiration
0%
b) Photomorphogenesis
0%
c) Photoperiodism
0%
d) Phototropism
Explanation
Answer : (c)
Q.45
Cytokinins .... .... [RPMT 1998]
0%
a) Induce cell division and inhibit ageing
0%
b) Maintain dormancy
0%
c) Induce abscission
0%
d) Inhibit cell division
Explanation
Cytokinins Functions 1. Cell division 2. Cell differentiation 3. Leaf senescence 4. Inflorescence growth 5. Nutrient mobilization 6. Cotyledon expansion 7. Apical dominance 8. inhibit ageing Answer : (a)
Q.46
Photomorphogenetic pigment in plants is ... .... [ Pb PMT 1999 ]
0%
a) Phytochrome system
0%
b) Chlorophyll
0%
c) Carotene
0%
d) Chalcone pigment
Explanation
Phytochromes are signaling proteins that promote photomorphogenesis in response to red light and far-red light. Phytochromes are proteins with a light absorbing pigment attached called a chromophore. Answer : (a)
Q.47
Hormone antagonistic to ABA is ... .... [ BHU 2012]
0%
a) Gibberellin
0%
b) Auxin
0%
c) Ethylene
0%
d) Cytokinin
Explanation
Abscisic acid
Gibberellic acid
It inhibits growth
It promotes growth
It promotes the dormancy of seeds, buds and tubers
It overcomes the natural dormancy of seeds, tubers, etc
It inhibits the synthesis of RNA and proteins
It promotes the synthesis of RNA and proteins
Causes abscission of flowers and fruits.
Promotes development of fruits
Promotes leaf senescence
Prevents leaf senescence
Promotes stomata closure
Promotes stomatal opening
Prevents amylase activity
Promotes amylase activity during seed germination
Answer : (a)
Q.48
Phototropic and geotropic movements are linked to .... .... [ BHU 1999 ]
0%
a) Gibberellins
0%
b) Enzymes
0%
c) Auxin
0%
d) Cytokinins
Explanation
Auxins hormone controls a plant response to light and gravity. It is made by the cells present at the tip of a stem and roots. Answer : (c)
Q.49
Phytochrome is associated with ... ... [ MPPMT 1993]
0%
a) Pr and Pfr reactions
0%
b) Absorption of red light of 660 nm
0%
c) Absorption of far-red light of 740 nm
0%
d) Absorption of blue-light by leaves
Explanation
Phytochromes have two photo-interconvertible forms: Pr and Pfr. Pr absorbs red light (~667 nm) and is immediately converted to Pfr. Pfr absorbs far-red light (~730 nm) and is quickly converted back to Pr. Answer : (a)
Q.50
Lateral axillary buds are not allowed to grow by ... .. [ CPMT 1996]
0%
a) Auxin
0%
b) Ethylene
0%
c) Gibberellin
0%
d) Cytokinin
Explanation
Shoot apical meristem produces auxin which prevents axillary buds from growing Answer : (a)
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