Chapter 1 Sensitivity And Response In Plants Summary
” The environment of an organism is dynamic and is always changing. Response against these favorable and unfavorable changes is called sensitivity.
These changes of the environment are called stimuli, example. sunlight is an external stimulus and water scarcity of a cell is an internal stimulus.
The response against stimulus in plants is seen in the folding of leaves in the touch-me-not plant (Mimosa pudica) and the vertical movement of lateral leaflets of Desmodium gyrans. Famous scientist Acharya Jagadish Chandra Bose measures the response by ‘Crescograph’.
There are three types of movement in plants viz. Tropic movement, tactic movement, and nastic movement.
Tactic movement is a locomotion movement in response to a stimulus eg. movement of volvox towards the light.
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Tropic movement is the movement of plant parts (stem, branch or root tip) towards the direction of stimulus. Like phototropic movement or movement towards the light, hydrotropic movement or movement towards the water, and geotropic movement or movement towards gravity.
Movement according to the intensity of the stimulus is the nastic movement like-flowering in the high intensity of light in sunflower (photo-nasty), flowering in high temperature in tulip (thermonasty), folding of leaves due to touch in Mimosa (seismonasty), and trapping of insects in insectivorous plants (chemo nasty).
There are various similarities and dissimilarities between these three types of movements.
Chapter 1 Sensitivity And Response In Plants Long Answer Type Questions
Question 1. How do plants sense any change in their surroundings? Explain the event of response shown by plants, with suitable examples.
Answer:
Sensing the changes in surroundings by plants:
It is now established that all living organisms respond to various stimuli, but the magnitude varies widely. It was earlier thought that only animals respond to stimuli.
However, modem scientists have proved that several plants can respond to stimuli like animals. Most of plants are unable to perform locomotion, though almost all plants respond to any change in the surroundings by the movement of their different body parts.
Examples of response shown by plants:
Response to stimuli by any plant is a slow and minutely perceptible event. It occurs by growth or changes in turgor pressure in certain parts of the plant body.
In some plants like the touch-me-not plant and telegraph plant response to stimuli is distinctly visible. This can be explained as follows—
In the touch-me-not plant (Mimosa pudica), leaflets fold and droop in response to touch. It is seen that the response becomes. quicker and more intense when the impact is stronger.
In the telegraph plant (Desmodium gyrans), the two lateral leaflets incessantly move up and down all day long. As the sun goes down, the movement stops.
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Question 2. Describe the contribution of Sir Jagadish Chandra Bose in proving the sensitivity of plants. What do growth movement and variation movement mean?
Answer:
Contribution of Sir Jagadish Chandra Bose in proving the sensitivity of plants:
Sir Jagadish Chandra Bose was the pioneer scientist in establishing the fact that plants also have sensitivity, like animals. For his experiment on plant sensitivity, he selected a touch-me-not plant and a telegraph plant.
He invented a sensitive instrument, known as a crescograph, for this purpose, which was capable of measuring any mildest response by the plants. From his experimental results, he concluded that—
- Like animals, plants are also capable of performing rhythmic actions, which control the movements due to sensitivity.
- Various different external stimuli, like touch, heat, cold, etc. cause changes in protoplasm, which is reflected as a response.
Growth movement:
Due to unequal growth of the meristematic region, plant parts show some movement of curvature. This type of movement is known as the growth movement.
Example: Twiningoftendrils around their support, in one direction.
Variation movement:
Variation in pressure in the tissues causes movement in some plant organs. This is called variation movement.
Example: This is seen in the leaflets of the telegraph plant.
Question 3. What does plant movement mean? Schematically represent different types of induced movement in plants.
Answer:
Plant movement:
The process, by which plants move their body parts, by staying stationary in their position, either spontaneously or in response to external stimuli, is called plant movement. Movement is a sign of sensitivity among plants.
Almost all plants perform a movement, except a few lower plants, which perform locomotion by displacement of the whole body or certain cells.
Different types of induced movement in plants:
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Induced movement in plants can be classified under three main types—tactic movement, tropic movement, and nastic movement.
Of these three, tactic movement involves overall displacement of the plant body, whereas, tropic and nastic movements are the movements of curvature. The schematic representation of different types of induced plant movements is given below.
Question 4. Mention the salient features of tactic movement. Define phototactic movement with an example.
Answer:
Salient features of tactic movement:
Tactic movement is a special type of movement. Its main features are—
- In this movement, the whole plant body is displaced.
- Tactic movement is controlled by both direction and intensity of the stimuli.
- Cilia and flagella help in tactic movement.
- Tactic movement is seen among phytoplanktons and germ cells of certain lower plants like fern and moss.
Phototactic movement:
The overall displacement of a plant or any plant cell in response to light, which serves as the external stimulus is called phototactic movement.
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Example:
Phytoplanktons like Chlamydomonas and Volvox travel towards an illuminated portion of the water body to get adequate light for photosynthesis. When the water surface becomes warmer, these phytoplanktons move to cooler regions.
In this case, sunlight serves as the stimulus for the tactic movement of these organisms.
Question 5. What do you mean by phototropic movement? Elucidate it with an experiment and a suitable diagram.
Answer:
Phototropic movement:
The induced movement of curvature in plants that is controlled by the direction of the source of light, is known as phototropic movement or phototropism.
The shoot of a plant grows towards the light source, thus, shoots of plants show positive phototropic movement. The roots of plants grow opposite to the source of light. In this way, roots perform a negative phototropic movement.
On the other hand, leaves grow at a right angle to the incident light; leaves, therefore, exhibit transverse phototropic movement.
Experiment:
A grown-up sapling is fitted in a water-filled bottle with a split cork, so that the roots remain inside the bottle and the shoot is held erect above the cork. This bottle is kept in a room near an open window keeping all other windows and doors closed.
After a few days, the shoot will bend towards the source of light, and root tips will grow to the opposite direction. This experiment indicates that the stem is positively phototropic and the root is negatively phototropic.
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Question 6. What do you mean by geotropic movement? Elucidate it with an experiment and a suitable diagram.
Answer:
Geotropic movement:
The induced movement of curvature in plants, which is controlled by the direction of gravity, is called geotropic movement or geotropism. The root of plants grows towards the source of gravity, whereas the shoot grows opposite to gravity.
Here roots exhibit positive geotropic movement and shoots show negative geotropic movement. The lateral branches of roots and sub-aerial modified stems of certain plants grow at a right angle to the direction of gravity, these organs show transverse geotropic movement.
Experiment:
The felt of a blackboard duster is dipped in water. A germinating gram seed is fixed on it with a paper pin without hurting the embryo. Now die setup is hung with a thread to keep the seed in a vertical position.
After a few days the plumule will grow upward and the radical will come downward. This experiment demonstrates that the shoot shows negative geotropism and root exhibits positive geotropism.
Question 7. What do vou mean by hydrotropic movement? Elucidate it with an experiment and suitable diagram.
Answer:
Hydrotropic movement:
The induced movement of curvature in plants, which is controlled by the direction of the source of water, is called hydrotropic movement or hydrotropism.
The roots grow towards the source of water, which is an example of positive hydrotropic movement. Shoots, on the other hand, grow opposite to the source of water and thereby, exhibit negative hydrotropic movement
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Experiment:
Wet sawdust is thickly spread on a wire mesh. Some fresh gram seeds are sown on it. The setup is hung in a slightly slanted manner so that water percolates to the lower side.
After some days the young roots will come out through the mesh downward due to geotropism. After the next few days, the root tips will turn back and enter through the mesh towards the wet region in search of water.
Life Science Class 10 Wbbse Question 8. How do light and gravity affect the movement of plants?
Answer:
Role of light in plant movement:
Light affects plant movement in different ways, which are mentioned below,
1. Phototropism:
This is a movement of curvature, where the direction of the source of light plays a major role. The shoot of a plant grows towards the light source, thus, shoots show positive phototropic movement.
The roots grow opposite to the source of light, in this manner, roots perform negative .phototropic movement. On the other hand, leaves grow at a right angle to the incident light.
Therefore, the leaves exhibit transverse phototropic movement. Auxin hormone internally controls this phototropism.
2. Phototaxis:
In this type of movement, the whole plant body (generally unicellular photosynthetic organisms) moves towards the source of light. Phytoplanktons, like Chlamydomonas and Volvox, travel towards an illuminated portion of the water body.
3. Photonasty:
This is a movement of curvature, controlled by the intensity of light. For instance, petals of sunflower and lotus bloom widely in bright daylight but they close in the evening.
Role of gravity in plant movement:
Gravity acts as stimulus for tropic movement in plants. The movement of curvature in plants, controlled by the direction of gravity is called geotropic movement.
The roots of the plant grow towards the source of gravity, whereas the shoot grows opposite to gravity. Here roots exhibit positive geotropic movement and shoots show negative geotropic movement.
The lateral branches of roots and modified sub-aerial stems of certain plants grow at right angle to the direction of gravity. These organs show transverse geotropic movement. Like phototropism, geotropism is also controlled by the hormone auxin.
Life Science Class 10 Wbbse Question 9. Mention the salient features of tropic and nastic movement.
Difference Between Tropic And Nastic Movement In Plants
Answer:
Salient features of tropic movement:
- It occurs by the formation of curvature in the plant body.
- This movement is controlled by the direction ofthe source of stimuli.
- Different external stimuli, like light, water, gravity, etc. induce this movement.
- It occurs in growing organs like roots, stems, and leaves.
- Growth regulators or plant hormones play an important role in this type of movement.
Salient features of nastic movement:
- It occurs by the formation of curvature in the plant body.
- This movement is controlled by the intensity of the stimulus.
- Different external stimuli, like light, temperature, touch, chemicals, etc. induce this movement.
Question 10. Compare tactic, tropic and nastic movements in plants.
Answer:
Comparison among tactic, tropic and nastic movements in plants
Chapter 1 Sensitivity And Response In Plants Short Answer Type Questions
Question 1. What do stimulus and sensation mean?
Answer:
Stimulus:
Any change in the surroundings or within the body, which any living organism perceives and responds accordingly, is called a stimulus.
Sensation:
The change or reaction that occurs within a living organism by the action of a stimulus is called sensation.
Question 2. Point out the relation between stimulus and sensation.
Answer:
Sensation develops in the presence of any stimulus. The stimulus can create at least some sensation in living organisms. Therefore, a stimulus can be treated as the cause and sensation is its immediate result.
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Question 3. What do external and internal stimuli mean?
Difference Between Tropic And Nastic Movement In Plants
Answer:
External stimuli:
The stimuli, which are generated in the environment or outside the body of any organism, but act on it to create sensation, are known as external stimuli. Example—Shoot of a plant grows towards light, where light is an external stimulus.
Internal stimuli:
The stimuli, which are generated within the body of an organism to create sensation, are known as internal stimuli. Example—Auxin hormone, produced inside the plant body, acts as an internal stimulus for phototropism.
Question 4. What is meant by plant sensitivity? Give an example.
Answer:
Plant sensitivity:
The ability of a plant to detect any change in the surroundings, or within the body and respond accordingly, is known as plant sensitivity.
Example:
If the leaves of touch-me-not plant (Mimosa pudica) is touched, they fold at once and droop, showing sensitivity.
Question 5. Explain the plant response towards stimulus with a suitable example.
Answer:
The plant response towards stimulus with a suitable example:
The Touch-me-not plant exhibits an instantaneous response toward stimulus (touch). When touched, the leaflets of touch-me-not plant fold at once, and the leaves droop.
The stimulus of touch reduces the turgor pressure in the tissue of the petiole and base of leaflets to show the response by drooping of those parts.
Question 6. How does a plant respond to a stimulus?
Answer:
A plant respond to a stimulus:
The responses of plants towards different stimuli are demonstrated by some biological processes, which mainly include growth, change in turgor pressure or free cellular movement.
Based on these biological processes, plants perform growth movement, drooping of leaves, up and down movement of lateral leaflets, opening and closing of flowers, and locomotion of gametes and unicellular forms in response to specific stimuli.
Question 7. What does the movement of variation mean?
Answer:
The movement of variation mean:
The spontaneous movement of curvature that occurs in some plants, due to changes in turgor pressure inside the tissues at certain portions of the plant body, is called the movement of variation.
Example:
The two lateral leaflets of the telegraph plant (Desmodium gyrans) move up and down continuously due to variations in turgor pressure in the tissues of its petioles.
Question 8. How many types of movements are seen in plants?
Difference Between Tropic And Nastic Movement In Plants
Answer:
Types of movement seen in plants can be classified into two main types—
- Overall movement or locomotion and
- Movement of curvature. Both these types can again be divided into spontaneous movement and induced movement.
Question 9. What is meant by overall movement or locomotion in plants?
Answer:
Overall movement or locomotion in plants:
Overall displacement of the entire plant 01 any plant part from one place to another, either spontaneously or in response to any external stimulus, is called overall movement or locomotion.
Example:
Chlamydomonas, and Volvox perform locomotion as they move towards an illuminated portion of the water body.
Life Science Class 10 Wbbse Question 10. what does the movement of curvature mean?
Answer:
Movement of any plant part, either spontaneously or in response to any stimulus, without overall displacement of the plant body, is called the movement of curvature.
Examples: Tropic movement, nastic movement, movement of variation, etc.
Question 11. What is induced movement in plants?
Answer:
Induced movement in plants:
Overall movement or movement of curvature that occurs in a plant in response to any external stimulus is called induced movement. In this process, light, gravitational pull, source of water, heat, chemicals, etc. act as external stimuli to induce the plants to move.
Example: Tropic movement, tactic movement, etc.
Question 12. How many types of induced movement are seen among plants?
Difference Between Tropic And Nastic Movement In Plants
Answer:
Generally three types of induced movements are seen among plants, these are—
- Tropic movement,
- Nastic movement and
- Tactic movement.
Tropic movement is induced by the direction of stimuli, whereas nastic movement is controlled by the intensity of the stimuli. Tactic movement is an overall movement of the plant body, controlled by both intensity and direction of tire stimuli.
Question 13. What is tactic movement or induced I locomotion? Give an example.
Answer:
Tactic movement:
The overall displacement of a plant or any plant cell in response to any external stimulus is called tactic movement or induced locomotion.
Example: Movement of Volvox and Chlamydomonas towards the sunlit zone of water.
Question 14. What is tropic movement or directional movement? Give one example.
Answer:
Tropic movement:
The induced movement of curvature in plants, which is controlled by the direction of the source of external stimulus, is known as tropic movement or directional movement.
Example: Growth of shoot towards the source of light is an example of tropic or directional movement.
Question 15. If the stem of a potted plant is placed horizontally to the ground for seven days. What will happen to it and why?
Answer:
If the stem of a potted plant is placed horizontally to the ground for seven days, it will bend upward, that is, vertically erect. This occurs due to the positively phototropic and negatively geotropic nature of the stem.
Question 16. What is meant by transverse geotropic movement?
Answer:
Transverse geotropic movement:
The induced movement of curvature, where most leaves grow transversely, or, at right angles to the direction of gravity, is known as transverse geotropic movement.
Question 17. What is photo nasty or photonastic movement?
Answer:
Photo nasty or photonastic movement:
The induced movement of curvature in plants, that is controlled by the intensity of light, is called photonastic movement or photo nasty.
Example: Blooming of sunflower petals in bright daylight and closing in the dim evening light.
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Question 18. What is the monastic movement or thermonasty?
Answer:
Monastic movement or thermonasty
The induced movement of curvature in plants, that is controlled by the intensity of temperature of the surroundings, is known as thermoplastic movement or thermonasty.
Example: Tulip flowers bloom in higher temperatures but the petals close when the temperature is low.
Question 19. What is seismonasty or seismonastic movement?
Answer:
Seismonasty or Seismonastic movement:
The induced movement of curvature in plants, that is controlled by touch, friction, vibration or any mechanical impact, is called seismonastic movement or seismonasty.
Example: The leaflets of the touch-me-not plant fold when being touched.
Question 20. What is the monastic movement or chemo nasty?
Answer:
Monastic movement or chemo nasty:
The induced movement of curvature in plants that is controlled by the concentration or ‘ harshness of any chemical. the substance is called the monastic movement or chemo nasty.
Example:
Folding of the leaf lamina of venus flytrap plapt in contact with insect protein when an insect sits on it.
Question 21. Which types of tropic movement are noticed in stems and roots of plants?
Answer:
Tropic movement in stems:
The nature of tropic movements noticed in the stems of plants are positive phototropism, negative geotropism, and negative hydrotropism.
Tropic movement in roots:
The nature of tropic movement noticed in the roots of plants are negative phototropism, positive geotropism, and positive hydrotropism.
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Question 22. Mention the importance of movement in plants.
Answer:
The importance of movement in plants are as follows—
- Growth movement of the root tip occurs in search of water and mineral salts from the soil.
- Movement of the stem is important in order to get adequate sunlight and air.
Question 23. Distinguish between tropic and nastic movements.
Or, Write two differences between tropic and nastic movements.
Answer:
Distinguishing features between tropic and nastic movements are—
Question 24. Distinguish between tropic and tactic movements.
Answer:
Distinguishing features between tropic and tactic movements arc-
Question 25. Distinguish between movement and locomotion.
Answer:
Distinguishing features between movement and locomotion are—
Question 26. Distinguish between phototropic and phototactic movements.
Answer:
Distinguishing features between phototropic and phototactic movements are—
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Question 27. Distinguish between nastic and tactic movements.
Answer:
Distinguishing features between nastic and tactic movements are—
Question 28. Distinguish between phototropic and photonastic movements.
Answer:
Distinguishing features between phototropic and photonastic movements are
Chapter 1 Sensitivity And Response In Plants Very Short Answer Type Questions Multiple Choice Questions And Answers
Question 1. The ability of an organism to detect the changes in the environment and respond according to it, is called—
- Accommodation
- Stimulus
- Sensitivity
- Synthesis
Answer: 3. Sensitivity
Question 2. Stimulus is a type of—
- Sensation
- Observation
- Response
- Energy
Answer: 4. Energy
Question 3. The movement, controlled by the intensity of the stimulus is called—
- Tropic movement
- Tactic movement
- Nastic movement
- Chemotaxis
Answer: 3. Nastic movement
Question 4. An example of an internal stimulus is—
- Change in turgor pressure inside a cell
- Change in the intensity of light
- Gravitation
- Touch
Answer: 1. Change in turgor pressure inside a cell
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Question 5. Blooming of lotus flowers in bright daylight is an example of—
- Nastic movement
- Tactic movement
- Tropic movement
- Movement of variation
Answer: 1. Nastic movement
Question 6. Which plant, other than the ‘telegraph plant’, did Sir Jagadish Chandra Bose work upon?
- Touch-me-not plant
- Sunflower
- Tulip
- Sweet pea plant
Answer: 1. Touch-me-not plant
Question 7. Movement of the whole plant body, controlled by external stimuli, is called—
- Movement of variation
- Nastic movement
- Tropic movement
- Tactic movement
Answer: 4. Tactic movement
Question 8. Tropic movement controlled by sunlight is called—
- Hydrotropic movement
- Chemotropic movement
- Geotropic movement
- Phototropic movement
Answer: 4. Phototropic movement
Question 9. Displacement of the whole plant body by the stimulation of light is called—
- Photonasty
- Phototropism
- Spontaneous movement
- Phototaxis
Answer: 4. Phototaxis
Question 10. The movement of curvature in plant body, which is controlled by the direction of stimulus, is called—
- Tropic movement
- Tactic movement
- Nastic movement
- Circumnutation
Answer: 1. Tropic movement
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Question 11. When nastic movement of any plant part occurs by the action of any chemical substance, it is called—
- Their monastic movement
- Chemonastic movement
- Nyctinastic movement
- Seismonastic movement
Answer: 2. Chemonastic movement
Question 12. The tentacles or leaves of an insectivorous plant, called sundew bend to trap the insect as soon as they come on contact with the insect body. This is—
- Seismonasty
- Thermonasty
- Photonasty
- Chemonasty
Answer: 4. Chemonasty
Question 13. Petals of jasmine bloom at night. Which type of movement is this?
- Photonastic movement
- Chemonastic movement
- Their monastic movement
- Seismonastic movement
Answer: 1. Photonastic movement
Question 14. The pneumatophores of Sundari trees come out above the soil. Which type of movement is this?
- Positive hydrotropic movement
- Negative geotropic movement
- Positive geotropic movement
- Negative phototropic movement
Answer: 2. Negative geotropic movement
Question 15. Among the following organisms, the which is capable of locomotion is—
- Mucor
- Yeast
- Penicillium
- Chlamydomonas
Answer: 4. Chlamydomonas
Question 16. The lateral leaflets of the ‘telegraph plant’ perform—
- Geotropic movement
- Photonastic movement
- Movement of variation
- Seismonastic movement
Answer: 3. Movement of variation
Question 17. The environmental factor, that may cause sensitivity in a living organism, is called—
- Energy
- Force
- Stimulus
- Adaptation
Answer: 3. Stimulus
Question 18. The reaction produced by the effect of a stimulus is called—
- Sensitivity
- Response
- Effector
- Receptor
Answer: 2. Response
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Question 19. The plant, which clearly exhibits sensitivity, is—
- Water hyacinth
- Lotus
- Touch-me-not plant
- Vasak
Answer: 3. Touch-me-not plant
Question 20. The scientist famous for his research works on the sensitivity of plants is—
- Dr. C V Raman
- Dr. Edward Jenner
- Prafulla Chandra Roy
- Jagadish Chandra Bose
Answer: 4. Jagadish Chandra Bose
Question 21. Which of the following is not an external stimulus for creating a response among plants?
- Poison
- Hormone
- Heat
- Touch
Answer: 2. Hormone
Question 22. Two lateral leaflets of the trilaminate leaf of this plant can move up and down continuously. This is —
- Sundari tree
- Lotus
- Telegraph plant
- Basil
Answer: 3. Telegraph plant
Question 23. The factor responsible for the movement of variation is—
- Increase in the number of cells
- Variation in turgor pressure within cells
- Increase in the number of vacuoles inside the cells
- Variation in temperature within cells
Answer: 2. Variation in turgor pressure within cells
Question 24. Among the following, photonastic movement is seen in—
- Sunflower plant
- Insectivorous plants
- Touch-me-not plant
- Sundari plant
Answer: 1. Sunflower plant
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Question 25. The scientist who worked with crescographs is—
- Satyendra Nath Bose
- Jagadish Chandra Bose
- Prafulla Chandra Roy
- Charles Newton
Answer: 2. Jagadish Chandra Bose
Question 26. The movement of plants that is regulated by the direction of the water source is called—
- Geotropic movement
- Phototropic movement
- Hydrotropic movement
- Hydrotactic movement
Answer: 3. Hydrotropic movement
Question 27. The overall change in the position of an organism is called—
- Movement
- Rotation
- Locomotion
- Displacement
Answer: 2. Rotation
Question 28. The organism, Which demonstrates locomotion, is—
- Mucor
- Volvox
- Mimosa pudica
- Telegraph plant
Answer: 2. Volvox
Question 29. Swimming of the male gametes of fern towards the egg cell due to malic acid is an example of—
- Chemonastic movement
- Chemotactic movement
- Chemotropic movement
- Chemosynthetic movement
Answer: 2. Chemotactic movement
Question 30. In the morning, Chlamydomonas swim towards the water surface of the pond, which is an example of—
- Phototropic movement
- Photonastic movement
- Phototactic movement
- All of these
Answer: 3. Phototactic movement
Question 31. Which of the following performs locomotion by flagella?
- Chlamydomonas
- Spermatozoa of moss
- Spermatozoa of fern
- All of these
Answer: 4. All of these
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Question 32. Movement of plant parts due to change in hydrostatic pressure inside the cell by the effect of an external stimulus is—
- Tropic movement
- Tactic movement
- Chemotactic movement
- Nastic movement
Answer: 4. Nastic movement
Question 33. The stimulus for heliotropic movement is—
- Rainwater
- Sunlight
- Temperature fluctuation
- Touch
Answer: 2. Sunlight
Question 34. Phototropic movement in the shoot of a plant is controlled by—
- Auxin
- Light
- Different growth regulators
- Both 1 and 2
Answer: 4. Both 1 and 2
Question 35. Some flowers are open after sunrise and close after sunset. This is—
- Photonasty
- Seismonasty
- Chemonasty
- Thermonasty
Answer: 1. Photonasty
Question 36. Select which of the following statement is correctly related to tropic movement—
- It is controlled by the intensity of the stimulus.
- The overall change of place takes place by a plant or part of the plant
- This movement is observed in the algae called Volvox
- It is an induced movement of curvature controlled by the direction of the stimulus
Answer: 4. It is an induced movement of curvature controlled by the direction of the stimulus
Chapter 1 Sensitivity And Response In Plants Answer In A Single Word Or Sentence
Question 1. How do you designate any change in the environment or any substance that creates a response in an organism?
Answer: Stimulus
Question 2. Mention the types of stimuli based on their source.
Answer: Based on their sources stimuli are of two types—external stimuli and internal stimuli.
Question 3. Give an example of an external stimulus.
Answer: Light
Question 4. Mention one sign of response by any organism.
Answer: Movement
Question 5. Which famous scientist proved that sensitivity might develop in plants without physical shock?
Answer: Sir Jagadish Chandra Bose
Question 6. How do you denote the movement of different parts of a plant, fixed to the soil?
Answer: Movement of curvature
Question 7. How do you denote the movement of curvature of any organ in plants in response to external stimuli?
Answer: Induced movement of curvature
Question 8. How do you name the movement of the whole organism or parts of it, in response to internal stimuli?
Answer: Spontaneous movement
Question 9. Mention the scientific name of the telegraph plant.
Answer: Desmodium gyrans
Question 10. Mention the scientific name of the touch-me-not plant.
Answer: Mimosa pudica
Question 11. In which plant do you find negative geotropic movement?
Answer: Mangrove plants (pneumatophores)
Question 12. How do you denote the growth movement of leaves and modified sub-aerial stem present at a right angle to the direction of light?
Answer: Transverse phototropic movement
Question 13. How do you denote the growth movement of leaves and modified sub-aerial stem present at a right angle to the direction of light?
Answer: Transverse phototropic movement
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Question 14. Give an example of positive phototropism.
Answer: The movement of the stem of the plant towards the source of light is an example of positive phototropism.
Question 15. In which type of plants do you find the monastic movement?
Answer: Insectivorous plants like Venus flytraps, sundew, etc. show monastic movement.
Question 16. The root grows through the soil towards the source of water. Which type of movement is it?
Answer: Positive hydrotropic movement
Question 17. Which type of movement is seen in the shoot of a plant in response to water?
Answer: Negative hydrotropic movement
Question 18. The prop roots of the banyan tree grow straight toward the soil. Which type of movement is it?
Answer: Positive hydrotropic movement.
Question 19. The main stem of a plant always grows opposite to gravity. Which type of movement is this?
Answer: Negative geotropic movement
Question 20. The lateral branches of the root and stem grow at the right angle to the direction of gravity. Which type of movement is this?
Answer: Transverse geotropic movement
Question 21. What is nastic movement?
Answer: The induced movement of curvature in plants, which are controlled by the intensity of the stimulus, is called nastic movement
Question 22. How do you denote the blooming of sunflower petals in the morning and closing them in the evening?
Answer: Photonastic movement
Question 23. Opening and closing of tulip petals i response to increase and decrease in atmospheric temperature is an example of which type of movement?
Answer: Thermonastic movement
Question 24. How do you denote the event of overall displacement of algal bloom from a drier region towards a water-rich region?
Answer: Hydrotactic movement
Chapter 1 Sensitivity And Response In Plants Fill In The Blanks
Question 1. Hormone is type of _________ stimulus.
Answer: Internal
Question 2. All living organisms show a sign of _________ to a stimulation.
Answer: Response
Question 3. Leaves of touch-me-not plant respond to _________.
Answer: Touch
Question 4. Acharya Jagadish Chandra Bose proved the property of _________ by sending electrical impulses in Mimosa and Desmodium plants.
Answer: Sensitivity
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Question 5. The instrument, used to determine the sensitivity of plants, designed by Sir Jagadish Chandra Bose, is known as _________.
Answer: Crescograph
Question 6. The overall displacement or _________ is found in unicellular plants or plant germ cells.
Answer: Locomotion
Question 7. By the movement of taproots opposite to the source of light, a plant shows _________ phototropic movement.
Answer: Negative
Question 8. In an alga named _________,we see phototactic movement.
Answer: Chlamydomonas/ volvox
Question 9. Tropic movement stimulated by gravity is called _________ movement.
Answer: Geotropic
Question 10. Other name of the tropic movement is _________ movement.
Answer: Directional
Question 11. Auxin hormone controls _________ movement.
Answer: Tropic
Question 12. In the case of both phototactic and photonastic movements, _________ acts as the common stimulus.
Answer: Light
Question l3. By means of _________ movement, plant parts show permanent growth.
Answer: Tropic
Question 14. Tropic movement is controlled by the _________ of the stimulus
Answer: Direction
Question 15. Phototropism is also known as _________.
Answer: Heliotropism
Question 16. Leaves and lateral branches of modified sub-aerial stem show _________ phototropic movement.
Answer: Transverse
Question 17. Movement of _________ is noticed in the two lateral leaflets of the telegraph plant.
Answer: Variation
Question 18. Negative _________ movement is noticed in the pneumatophores of halophytes.
Answer: Geotropic
Question 19. The gravity of the earth acts as the stimulus for _________ movement.
Answer: Geotropic
Chapter 1 Sensitivity And Response In Plants State True Or False
Question 1. Sir Jagadish Chandra Bose worked telegraph plant.
Answer: True
Question 2. The stimulus may be either external or internal.
Answer: True
Question 3. Movement due to change in hydrostatic pressure is treated as growth movement.
Answer: False
Question 4. The age of plants can be determined by crescograph.
Answer: False
Question 5. Positive hydrotropic movement is noticed in the shoots of plants.
Answer: False
Question 6. Photonastic movement is seen in sunflowers and lotus.
Answer: True
Question 7. Leaflets of touch-me-not plant show seismonastic movement.
Answer: True
Question 8. Tropic movement is the movement of growth in plants.
Answer: True
Question 9. Tactic movement is a type of growth movement.
Answer: False
Question 10. Photo nasty is seen in the evening primrose flower.
Answer: True
Question 11. Chemotactic movement is noticed in the leaves of the Venus flytrap.
Answer: False
Question 12. Tropic movement is of five types.
Answer: False
Question 13. Tropic movement is controlled by hormones.
Answer: True
Question 14. Transverse geotropism is seen in lateral branches of roots.
Answer: True
Question 15. Nastic movement is not concerned with growth.
Answer: True
Question 16. Phototactic and phototropic movements are the same.
Answer: False
Question 17. Tropic movement is a movement of curvature.
Answer: True
Question 18. The tulip flower is seen in Kashmir because it blooms in low temperatures.
Answer: False
Question 19. Chemonasty occurs according to the direction of the stimulus.
Answer: False
Chapter 1 Sensitivity And Response In Plants Match The Columns
1.
.
Answer: 1. C, 2. D, 3. B, 4. E, 5. F, 6. G
2.
Answer: 1. B, 2. A, 3. F, 4. C, 5. G, 6. D
3.
Answer: 1. E, 2. A, 3. B, 4. D, 5. C, 6. G
4.
Answer: 1. E, 2. D, 3. B, 4. G, 5. A, 6. C
Chapter 1 Sensitivity And Response In Plants Find The Odd One Out
Question 1. Movement of variation, Negative phototropism, Seismonasty, Photonasty
Answer: Movement of Variation
Question 2.Crescograph, Arc indicator, Electric probe, Resonance recorder
Answer: Arc indicator
Question 3. Movement of algae towards an illuminated portion of the pond, Movement of sperms towards malic acid, Movement- of the stem towards the source of light, Movement of phytoplanktons to the surface of water body during the daytime
Answer: Movement of stems towards the source of light
Question 4. Rotation of protoplasm, Circulation of protoplasm, Ciliary movement, Movement of variation
Answer: Movement of variation
Question 5. Hormone, Light, Temperature, Injury
Answer: Hormone
Question 6. Nastic, Tropic,Tactic, Gastric
Answer: Gastric
Question 7. Chlamydomonus, Voluox, Agaricus, Diatom
Answer: Agaricus
Question 8. Phototropic, Hydrotropic, Geotropic, Photonastic
Answer: photonastic
Chapter 1 Sensitivity And Response In Plants Fill In The blanks By Looking At The First Pair
Question 1. Negative phototropism: Root :: Transverse phototropism _______.
Answer: Leaves
Question 2. Positive geotropism : Root:: Positive photo¬tropism: _______
Answer: Stem
Question 3. Heat: Thermonasty:: Vibration: _______
Answer: Seismonasty
Question 4. Opening of tulip petals: Thermonasty:: Opening of sunflower petals: _______.
Answer: Photonasy
Question 5. Phototactic movement: Algae:: Chemotactic movement: _______.
Answer: Fern antherozoid
Question 6. Phototropic movement: Light:: Hydrotropic movement: _______.
Answer: Water
Question 7. Touch-me-not plant: Seismonastic movement:: Sundew: _______.
Answer: Chemonastic movement
Question 8. The direction of stimulus: Tropic movement:: Intensity of stimulus: _______.
Answer: Nastic movement