Chapter 5 Quiz 1 (2nd Secondary Biology)
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The root of a plant growing down, then this phenomenon is a...
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Geotropism
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Phototropism
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Haptotropism
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Hydrotropism
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Are you looking for practice questions and answers from class 11, Biology chapter 5, for your exam? Check out this trivia quiz and make your practice level better. This quiz consists of questions from the chapter "Morphology of Flowering Plants." There are two systems present in flowering plants- the root system and the shoot system. A flower has four whorls; calyx, corolla, androecium, and gynoecium. Let's learn about the morphology of flowering plants in detail with this trivia quiz. We hope you secure good marks on this quiz and in your upcoming exam.
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- 2.
If a plant grows toward a light source, then it is said to be displaying _____?
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Negative phototropism
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Positive phototropism
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Negative geotropism
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Positive hydrotropisn
Correct Answer
A. Positive phototropismExplanation
Positive phototropism is the correct answer because it refers to the phenomenon where a plant grows towards a light source. Plants exhibit positive phototropism as they bend or grow towards the light in order to maximize their exposure to sunlight for photosynthesis.Rate this question:
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- 3.
An example of ______ is when a plant starts to coil around another type of plant.
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Positive geotropism
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Negative phototropism
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Positive haptotropism
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Positive hydrotropism
Correct Answer
A. Positive haptotropismExplanation
Positive haptotropism is the correct answer because haptotropism refers to the directional growth or movement of an organism in response to touch or contact stimuli. In this example, the plant is coiling around another type of plant in response to physical contact, which is an example of positive haptotropism.Rate this question:
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- 4.
Which part of the plant responds positively to gravity?
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Xylem
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Leaves
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Roots
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Stem
Correct Answer
A. RootsExplanation
Roots respond positively to gravity by growing downwards. This is known as geotropism or gravitropism. The roots have specialized cells called statocytes that contain dense starch grains, which settle under the influence of gravity. This helps the roots sense the direction of gravity and grow in the opposite direction, towards the center of the Earth. This allows the roots to anchor the plant in the soil and absorb water and nutrients from the ground.Rate this question:
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- 5.
Which parts of the plant display positive phototropism?
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Roots and stem
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Leaves and stem
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Leaves and roots
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All the above
Correct Answer
A. Leaves and stemExplanation
Phototropism is the growth or movement of an organism towards or away from light. Positive phototropism refers to the growth towards light. In plants, the stem and leaves are the parts that display positive phototropism. The stem grows towards the light source to maximize light absorption for photosynthesis, while the leaves adjust their position to receive optimal sunlight. The roots, on the other hand, exhibit negative phototropism, growing away from light sources, as they are responsible for anchoring the plant and absorbing water and nutrients from the soil.Rate this question:
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- 6.
The pad-like swelling at the base of each leaf of a sensitive plant is called
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Rachis
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Auricle
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Foliage
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Pulvini
Correct Answer
A. PulviniExplanation
The pad-like swelling at the base of each leaf of a sensitive plant is called pulvini. Pulvini are specialized structures found in certain plants that allow for rapid leaf movement. They are responsible for the plant's ability to fold its leaves in response to touch or other stimuli. This folding action is a defense mechanism that helps protect the plant from potential harm. The pulvini contain motor cells that respond to electrical signals, causing the leaves to move.Rate this question:
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- 7.
A student wanted to investigate the effect of light on the growth of cress seedlings. The student had three pots of seedlings grown in different conditions. One of the pots was placed with light from above. The second was placed in a cupboard with no light, while the third one was placed in a window with light from one direction only. The image shows the seedlings at the end of the investigation. What is the response shown by the cress seedlings in Pot (2)?
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Negative geotropism
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Negative phototropism
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Positive geotropism
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Positive phototropism
Correct Answer
A. Positive phototropismExplanation
The cress seedlings in Pot (2) were placed in a cupboard with no light. As a result, they grew straight up towards the only available light source, which is the opening of the cupboard. This is an example of positive phototropism, where the plants grow towards the light.Rate this question:
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- 8.
A student wanted to find out where the hormone that caused the response to directional light was found. The student had two growing plant shoots. He placed them both in a window with light coming from one direction. Describe a method the student could use to show that the hormone was found in the tip of the plant shoot.
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Remove the tip from one of the plant shoots and leave the other then measure the changes in growth.
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Remove the tip from both plant shoots then measure the changes in growth.
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Put one plant in light while the other in dark then measure the changes in growth.
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Put one plant in a light-proof box while the other in a place where light falls from one direction then measure the changes in growth.
Correct Answer
A. Remove the tip from one of the plant shoots and leave the other then measure the changes in growth.Explanation
By removing the tip from one of the plant shoots and leaving the other intact, the student can observe the changes in growth. If the hormone responsible for the response to directional light is found in the tip, the plant shoot with the removed tip would not show the expected response to light, while the intact shoot would continue to respond. This would indicate that the hormone is indeed located in the tip of the plant shoot.Rate this question:
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- 9.
Rapid movement of leaves of mimosa on touching is an example of
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Turgor movement
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Hydrotropism
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Geotropism
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Growth movement
Correct Answer
A. Turgor movementExplanation
The rapid movement of leaves of mimosa on touching is an example of turgor movement. Turgor movement is a type of movement in plants that occurs due to changes in turgor pressure within plant cells. When the leaves of mimosa are touched, there is a rapid loss of turgor pressure in the cells of the leaflets, causing them to fold and droop. This response is a protective mechanism to defend against potential harm or damage.Rate this question:
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- 10.
The experiment in the figure below shows that
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The root is positive geotropic
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The root is negative hydrotropic
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The root is positive hydrotropic
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The stem is positive phototropic
Correct Answer
A. The root is positive hydrotropicExplanation
The experiment in the figure shows that the root is positively hydrotropic. This means that the root is growing towards the water source. The root is bending and growing in the direction of the water, indicating a positive response to the presence of water.Rate this question:
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- 11.
Roots of a plant show
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Positive phototropism and negative geotropism
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Negative hydrotropism and positive phototropism
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Negative phototropism and positive geotropism
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Positive geotropism and negative hydrotropism
Correct Answer
A. Negative phototropism and positive geotropismExplanation
Roots of a plant exhibit negative phototropism, which means they grow away from light, and positive geotropism, which means they grow towards gravity. This is because roots need to anchor the plant in the soil and absorb water and nutrients, which are typically found in the ground. Therefore, they grow in the opposite direction of light and towards the force of gravity.Rate this question:
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- 12.
One of the following is not a growth dependent response
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Movement of roots towards gravity
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Movement of shoots away of gravity
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Drooping of leaves in response to touch
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Movement of shoots towards light
Correct Answer
A. Drooping of leaves in response to touchExplanation
Drooping of leaves in response to touch is not a growth dependent response because it is not influenced by the growth of the plant. The movement of roots towards gravity and movement of shoots towards light are growth dependent responses as they involve the growth of plant tissues in response to external stimuli. Similarly, the movement of shoots away from gravity is also a growth dependent response as it involves the growth of plant tissues in the opposite direction of gravity.Rate this question:
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- 13.
The movement of sunflower in accordance with the path of sun is due to...
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Heliotropism
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Geotropism
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Chemotropism
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Hydrotropism
Correct Answer
A. HeliotropismExplanation
The movement of sunflowers in accordance with the path of the sun is due to heliotropism. Heliotropism is the ability of plants to track the movement of the sun throughout the day. Sunflowers are known for their heliotropic behavior, as they face east in the morning and follow the sun as it moves across the sky, eventually facing west in the evening. This movement is controlled by specialized cells in the stem that respond to light and help the plant optimize its exposure to sunlight for photosynthesis.Rate this question:
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- 14.
....... is an example of the movement of a plant part which is very quick and can be observed easily.
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Touch movement in the leaves of Mimosa plant.
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Movement of stem towards light.
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Movement of roots away of light.
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Movement of sunflower towards sun.
Correct Answer
A. Touch movement in the leaves of Mimosa plant.Explanation
The correct answer is touch movement in the leaves of the Mimosa plant. This plant exhibits a rapid response to touch, where its leaves fold up or droop when touched. This movement can be easily observed and is a clear example of a plant part moving quickly in response to a stimulus.Rate this question:
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- 15.
Where is the auxin hormone made in a plant stem?
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At the tip of the stem.
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In the petals of flowers.
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In the leaves of the stem.
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Beneath the tip of the stem.
Correct Answer
A. At the tip of the stem.Explanation
Auxin hormone is produced at the tip of the stem in plants. This hormone plays a crucial role in plant growth and development, including cell elongation, root formation, and phototropism. It is synthesized in the apical meristem, which is present at the tip of the stem. From there, it is transported downwards to other parts of the plant, where it regulates various physiological processes.Rate this question:
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- 16.
Which figure shows the correct position of each of the parts (A) and (B) according to the stimulus...
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(1)
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(2)
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(3)
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None of them.
Correct Answer
A. (2) -
- 17.
Why is the folding up of the leaves of a sensitive plant on touching with a finger not a tropism?
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Because there is no change in the growth of the plant.
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Because the plant moves in all directions.
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Because auxins accumulate on both sides in unequal ratios.
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Because folding up of leaves is a touch-induced movement.
Correct Answer
A. Because there is no change in the growth of the plant.Explanation
The folding up of the leaves of a sensitive plant on touching with a finger is not a tropism because there is no change in the growth of the plant. Tropism refers to the directional growth response of a plant towards or away from a stimulus, such as light or gravity. In this case, the folding up of the leaves is a touch-induced movement, but it does not involve any growth or change in the overall direction of growth of the plant.Rate this question:
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- 18.
A growth movement of a plant part in response to an external stimulus in which the direction of stimulus determines the direction of response is called
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Sleeping movement
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Turgidity
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Tropism
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Touch movement
Correct Answer
A. TropismExplanation
Tropism is the correct answer because it refers to the growth movement of a plant part in response to an external stimulus, where the direction of the stimulus determines the direction of the plant's response. This can include movements such as phototropism (response to light), geotropism (response to gravity), and hydrotropism (response to water). Sleeping movement, turgidity, and touch movement do not accurately describe this specific type of growth response.Rate this question:
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- 19.
Which diagram shows a negative geotropism (A), (B), (C) or (D)?
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A
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B
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C
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D
Correct Answer
A. DExplanation
Diagram D shows a negative geotropism because the plant is growing in an upward direction, against the force of gravity. This can be observed by the stem and leaves extending vertically upwards. In contrast, diagrams A, B, and C show positive geotropism, as the plants are growing in the direction of gravity, with their stems and leaves bending downwards.Rate this question:
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- 20.
In the experiment shown in the figure below what will happen to the two coleoptiles (1) and (2) after some hours of the experiment? (the coleoptiles are not subjected to light).
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In (1), A bends towards B / In (2), A and B grow vertically upwards
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In (1), B bends towards A / In (2), A and B grow vertically upwards
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In (1), A bends towards B / In (2), B bends towards A
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In (1) A and B stop growth / In (2) B bends towards A
Correct Answer
A. In (1), B bends towards A / In (2), A and B grow vertically upwardsExplanation
In the experiment, coleoptile (1) bends towards coleoptile (2) because coleoptile (1) is subjected to a unilateral light source. This bending is known as phototropism, where plants grow towards the light source. Coleoptile (2) grows vertically upwards because it is not subjected to any light source. This is the natural growth pattern of plants in the absence of light. Therefore, after some hours of the experiment, coleoptile (1) will bend towards coleoptile (2), and coleoptile (2) will grow vertically upwards.Rate this question:
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- 21.
In the experiment shown in the figure below, why does coleoptile (A) bend while coleoptile (B) does not bend?
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Because auxins can diffuse through mica block but not though gelatin block.
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Because auxins can diffuse through both mica and gelatin blocks.
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Because auxins can’t diffuse through mica or gelatin blocks.
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Because auxins can diffuse through gelatin block but not through mica block.
Correct Answer
A. Because auxins can diffuse through gelatin block but not through mica block.Explanation
The figure shows an experiment where two coleoptiles, A and B, are placed next to mica and gelatin blocks. The question asks why coleoptile A bends while coleoptile B does not bend. The correct answer is that auxins, which are plant hormones responsible for bending growth, can diffuse through the gelatin block but not through the mica block. This suggests that the presence of auxins on one side of the coleoptile, diffusing through the gelatin block, causes it to bend towards that side. However, since auxins cannot diffuse through the mica block, coleoptile B does not receive auxins and therefore does not bend.Rate this question:
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- 22.
What happens if the tip of oat coleoptile is separated by a glass sheet, then it is exposed to light from one direction?
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Geotropism will take place
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Hydrotropism will take place
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Nothing will happen
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Phototropism will take place
Correct Answer
A. Nothing will happenExplanation
If the tip of the oat coleoptile is separated by a glass sheet and then exposed to light from one direction, nothing will happen. This is because the tip of the coleoptile is responsible for sensing light and initiating phototropism, which is the growth or movement of an organism in response to light. However, when the tip is separated by a glass sheet, it is unable to detect the light and therefore cannot initiate phototropism.Rate this question:
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- 23.
High concentrations of auxins causes
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Elongation of root cells
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Inhibition of elongation of root cells
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Elongation of both root and stem cells
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Inhibition of elongation of stem cells
Correct Answer
A. Inhibition of elongation of root cellsExplanation
High concentrations of auxins inhibit the elongation of root cells. Auxins are plant hormones that regulate various growth processes, including cell elongation. At low concentrations, auxins promote cell elongation, but at high concentrations, they have an inhibitory effect. This is because high levels of auxins can disrupt the balance of other hormones and signaling pathways involved in cell growth, leading to the inhibition of root cell elongation.Rate this question:
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- 24.
In the experiment shown in the figure below, what will happen to each of coleoptiles (A) and (B) after leaving the experiment for several hours?
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(A) will not bend / (B) will bend towards light
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Both (A) and (B) will bend towards light
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Both (A) and (B) will not bend
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(A) will bend towards light / (B) will not bend
Correct Answer
A. (A) will not bend / (B) will bend towards lightExplanation
In the experiment, the coleoptiles (A) and (B) are exposed to light. Coleoptile (A) will not bend because it has been covered with an opaque cap, preventing light from reaching it. On the other hand, coleoptile (B) is exposed to light, causing it to bend towards the light source. This is known as phototropism, a plant's growth response to light. Therefore, the correct answer is that (A) will not bend, while (B) will bend towards light.Rate this question:
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- 25.
The attitude of Venus Flytrap plant towards insects is described as -------.
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Nastic Movement
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Negative Gravitropism
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Haptotropism
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Hydrotropism
Correct Answer
A. Nastic MovementExplanation
The attitude of Venus Flytrap plant towards insects is described as nastic movement. Nastic movement refers to the non-directional response of a plant to a stimulus, such as the closing of the Venus Flytrap's leaves when an insect touches its trigger hairs. This movement is not dependent on the direction of the stimulus, but rather a general response to it.Rate this question:
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- 26.
What form of tropism is taking place when an ivy plant wraps itself around a stick or a string?
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Haptotropism
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Gravitropism
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Hydrotropism
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Phototropism
Correct Answer
A. HaptotropismExplanation
Haptotropism is the correct answer because it refers to the plant's response to touch or contact. In this case, the ivy plant is exhibiting haptotropism by wrapping itself around a stick or string, which is a form of contact. The plant is able to sense the presence of the object and responds by growing and wrapping around it, using it for support. This behavior allows the ivy plant to climb and reach higher positions for better access to sunlight.Rate this question:
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- 27.
Which experiment shows the correct response to a coleoptile if a foil collar is placed below its tip as in the figures below?
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A
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B
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C
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D
Correct Answer
A. BExplanation
The correct answer is B because in the figure, the coleoptile is bending away from the light source, indicating a positive phototropic response. Placing a foil collar below the tip of the coleoptile blocks the light from reaching the lower side, causing the coleoptile to bend towards the light source. This experiment demonstrates that light plays a role in the direction of coleoptile growth.Rate this question:
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- 28.
Which responses are the correct ones that the shoot (R) is going to take with respect to the direction of light falls on it as shown below?
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1 and 4
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2 and 3
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1 and 3
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2 and 4
Correct Answer
A. 2 and 4Explanation
The shoot (R) is going to take responses 2 and 4 with respect to the direction of light falls on it.Rate this question:
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- 29.
In the stem shown in the figure below, which area its cells are elongated more than the others by the effect of the IAA produced in the meristems of the stem?
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C
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B
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D
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A
Correct Answer
A. BExplanation
The correct answer is B because the question asks which area of the stem has cells that are elongated more than the others due to the effect of IAA produced in the meristems. Since IAA is a plant hormone that promotes cell elongation, the area where the cells are elongated the most would be where the IAA is most concentrated. In the given stem, area B is located closest to the meristems where IAA is produced, so it is likely to have the highest concentration of IAA and therefore the most elongated cells.Rate this question:
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- 30.
Which statement about auxin is true?
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High concentration of auxin inhibits the cell elongation in roots.
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High concentration of auxin stimulates the cell elongation in roots.
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High concentration of auxin inhibits the cell elongation in stems.
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Stems are much more sensitive to auxin than the roots.
Correct Answer
A. High concentration of auxin inhibits the cell elongation in roots.Explanation
Auxin is a plant hormone that plays a crucial role in regulating growth and development. In roots, a high concentration of auxin inhibits cell elongation. This is because auxin promotes the growth of root hairs and lateral roots, rather than elongation of the main root. Therefore, the correct statement is that a high concentration of auxin inhibits the cell elongation in roots.Rate this question:
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- 31.
The following figure is for a seedling which was attached on a surface that rotates horizontally where it was subjected to light from one direction only. If you know that the seedling had been rotating for two days then it was stopped for another two days. Which of the following figures illustrate what happened to the plumule of the seedling after the four days?
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A
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B
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C
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D
Correct Answer
A. D -
- 32.
The figure below represents some parts of the Mimosa plant. What happens to these parts at night?
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Part (Y) hangs down so part (X) shrinks
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Part (X) shrinks so part (Y) hangs down
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Part (X) shrinks so water diffuses to it from part (Y)
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Water diffuses from part (Y) so part (X) shrinks
Correct Answer
A. Part (X) shrinks so part (Y) hangs down -
- 33.
The following diagram illustrates the effect of auxins on a structure (X) in a certain plant. What does the structure (X) represent?
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Root
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Stem
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Underground stem
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Leaf
Correct Answer
A. RootExplanation
The diagram shows the effect of auxins on a structure, which is represented by X. Auxins are plant hormones that promote root growth. Therefore, the structure X in the diagram represents the root of the plant.Rate this question:
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- 34.
Which of the following is an example of the effects of gravitropism?
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Monarch butterflies migrate from Canada to Mexico each year.
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A hippopotamus submerges itself in water until the Sun goes down.
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A wilted flower returns to an upright position after being watered.
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A potted plant falls on its side, but it roots still grow downward.
Correct Answer
A. A potted plant falls on its side, but it roots still grow downward.Explanation
Gravitropism is the growth or movement of a plant in response to gravity. In this example, the potted plant falls on its side, but its roots still grow downward, showing the effect of gravitropism. The plant is able to sense the direction of gravity and adjust its growth accordingly, ensuring that its roots continue to grow in the downward direction.Rate this question:
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- 35.
In which of the following diagrams does phototropism enhance hydrotropism of the root?
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A
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B
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C
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D
Correct Answer
A. DExplanation
In diagram D, the root is bending towards the water source (hydrotropism) and also towards the light source (phototropism). This suggests that phototropism is enhancing the hydrotropism of the root, as it is guiding the root towards both the light and water sources.Rate this question:
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- 36.
When a plant root is subjected underground to water from only one direction. Which of the following graphs shown below, represents the correct rate of growth for the root parts?
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A
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B
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C
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D
Correct Answer
A. CExplanation
The correct rate of growth for the root parts when subjected to water from only one direction would be represented by graph C. This graph shows a gradual increase in growth over time, indicating that the root is receiving a steady supply of water. The other graphs either show no growth or inconsistent growth, which would not be expected when water is provided from one direction.Rate this question:
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- 37.
Which of the following statements is correct about the root being positively hydrotropic and the stem being positively phototropic?
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In both examples, auxins accumulate on the side of the root and that of the stem facing the stimulus.
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In both examples, the root and the stem will always bend in the same direction.
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In both examples, the effect of auxins on cells is the same.
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In both examples, the root and the stem bend towards the stimulus.
Correct Answer
A. In both examples, the root and the stem bend towards the stimulus.Explanation
In both examples, the root and the stem bend towards the stimulus because auxins accumulate on the side of the root and stem facing the stimulus. This accumulation of auxins causes the cells on that side to elongate and grow faster, resulting in bending towards the stimulus. Therefore, the correct statement is that the root and the stem bend towards the stimulus.Rate this question:
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- 38.
The diagram shows a simplified outline of a Mimosa leaf and a leaflet that has folded upward. Which letter represents the pulvinus?
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V
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X
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W
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Z
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Y
Correct Answer
A. WExplanation
The pulvinus is a joint-like structure found at the base of the leaflet that allows it to fold upward. In the given diagram, letter W represents the pulvinus as it is located at the base of the folded leaflet.Rate this question:
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- 39.
All of the following parts of the Mimosa plant would undergo some sort of movement as a result of the plant’s unique response to touch except the -------- .
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Leaflets
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Pulvini
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Stem
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Rachis
Correct Answer
A. StemExplanation
The Mimosa plant has a unique response to touch called thigmonasty, where its leaflets and pulvini (small swollen structures at the base of each leaflet) undergo rapid movement when touched. This movement is a defensive mechanism to protect the plant from potential threats. However, the stem does not undergo any significant movement in response to touch. Therefore, the correct answer is stem.Rate this question:
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- 40.
Which of the following is correct about the leaves of a Mimosa plant?
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Compound and pinnate with four secondary rachises
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Simple and pinnate with three secondary rachises and one primary rachis
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Compound and pinnate with three secondary rachises and one primary rachis
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Simple and pinnate with four secondary rachises
Correct Answer
A. Compound and pinnate with four secondary rachisesExplanation
The correct answer is compound and pinnate with four secondary rachises. This means that the leaves of a Mimosa plant are composed of multiple leaflets arranged in a feather-like pattern along a central axis (primary rachis). Each leaflet is further divided into smaller leaflets (secondary rachises), with a total of four secondary rachises branching off from the primary rachis.Rate this question:
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- 41.
Which of the following is true about the waking movement of a Mimosa plant?
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Water moves to the cells in the lower half of primary pulvini, causing these cells to become turgid.
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Water moves to the cells on the lower side of secondary rachises, causing them to become turgid.
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Water moves outside of the cells on the lower side of primary rachis, causing them to shrink.
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Water moves to the cells in the lower and upper halves of primary pulvini, causing them to become turgid.
Correct Answer
A. Water moves to the cells in the lower half of primary pulvini, causing these cells to become turgid.Explanation
Water moves to the cells in the lower half of primary pulvini, causing these cells to become turgid. This is true because the movement of water in the Mimosa plant is responsible for the plant's ability to fold and unfold its leaves in response to stimuli. The primary pulvini are specialized structures at the base of each leaflet that control leaf movement. When water moves into the cells in the lower half of the primary pulvini, it causes these cells to swell and become turgid, which results in the folding or closing of the leaf.Rate this question:
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- 42.
A growing plant was exposed to light from one side for a while. Which plant represents the growth rate of the growing tip cells of the part away of light in the stem of this plant?
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A
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B
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C
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D
Correct Answer
A. AExplanation
The correct answer is A because it shows that the growth rate of the growing tip cells of the part away from light in the stem of the plant is slower compared to the other options. This suggests that light is necessary for the optimal growth of the plant, and without it, the growth rate is reduced.Rate this question:
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- 43.
In an experiment to prove the role of auxins in plant growth, IAA was added gradually to the soil where Bean plant seedling grows. Which of the following graphs represent the effect of auxin on the growth of the growing tip cells of both the stem and the root of this seedling?
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A
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B
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C
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D
Correct Answer
A. BExplanation
Graph B represents the effect of auxin on the growth of the growing tip cells of both the stem and the root of the seedling. This is because the graph shows an increase in growth rate initially, followed by a decrease in growth rate. This is consistent with the known effects of auxins, which promote cell elongation and division in the early stages of growth, but inhibit growth at higher concentrations.Rate this question:
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- 44.
In which of the following cases is the concentration of auxin equal on both sides of a plant’s coleoptile?
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Hydrotropism
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Geotropism
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Phototropism
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None of the answers is correct
Correct Answer
A. HydrotropismExplanation
Hydrotropism is the growth or movement of a plant in response to water. In this case, the concentration of auxin, a plant hormone that regulates growth, is equal on both sides of the plant's coleoptile. This is because the plant is actively seeking water and therefore there is no concentration gradient of auxin that would cause differential growth. In contrast, geotropism is the growth or movement of a plant in response to gravity, and phototropism is the growth or movement of a plant in response to light. In both of these cases, there is a concentration gradient of auxin that causes differential growth, resulting in unequal concentrations of auxin on both sides of the coleoptile. Therefore, the correct answer is hydrotropism.Rate this question:
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- 45.
A student placed a potted plant horizontally in a dark room. He also covered the tip of the stem with aluminium foil. What did the student observe when he examined the plant after three days?
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The root and the stem grew straight horizontally.
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The root bent downwards, and the stem grew straight.
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The root bent downwards, while the stem bent upwards.
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The root bent upwards, while the stem bent downwards.
Correct Answer
A. The root bent downwards, while the stem bent upwards.Explanation
When the potted plant was placed horizontally in a dark room, the root of the plant bent downwards in response to gravity, while the stem of the plant bent upwards in search of light. This phenomenon is known as gravitropism, where the root grows in the direction of gravity and the stem grows against it. The aluminium foil covering the tip of the stem prevented it from receiving any light, causing it to grow in a direction opposite to gravity.Rate this question:
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- 46.
What can you infer from the following photo of a Mimosa plant?
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The photo was taken at night.
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The plant is grown in a horizontal position.
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The photo was taken during the daytime.
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The plant has been exposed to light from one direction.
Correct Answer
A. The photo was taken at night.Explanation
From the given information, we can infer that the photo was taken at night. The fact that the photo was taken at night is explicitly mentioned in the options and none of the other options provide any indication about the time of day or the position of the plant. Therefore, the only inference that can be made is that the photo was taken at night.Rate this question:
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- 47.
Which biological process explains why do some flowers open in the morning and close in evening?
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Respiration
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Excretion
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Photosynthesis
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Sensation
Correct Answer
A. SensationExplanation
Sensation is the process by which organisms detect and respond to stimuli in their environment. In the case of flowers opening in the morning and closing in the evening, this is a response to the stimulus of light. Flowers have specialized cells called photoreceptors that detect changes in light intensity. When light levels are high in the morning, the flowers open to maximize their exposure to sunlight for photosynthesis. As the day progresses and light levels decrease, the flowers close to protect their reproductive organs and conserve energy. This opening and closing of flowers is a sensory response to the changing light conditions.Rate this question:
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- 48.
Which of the following would be the appropriate stimulus and response for gravitropism?
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Stimulus= Touch; Response= Closure of leaves
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Stimulus= Gravity; Response= stem grows up
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Stimulus= gravity; Response= stem grows towards light
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Stimulus= Light; Response= root grows towards water
Correct Answer
A. Stimulus= Gravity; Response= stem grows upExplanation
Gravitropism is the growth or movement of a plant in response to gravity. In this case, the appropriate stimulus for gravitropism is gravity, as it is what triggers the plant's response. The response, on the other hand, is the stem growing up. This is because plants exhibit positive gravitropism, meaning they grow in the direction of gravity. Therefore, when the stimulus of gravity is present, the stem will grow in an upward direction.Rate this question:
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- 49.
When does phototropism enhance hydrotropism of the root?
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When both sides of the root face water and light together.
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When the root is exposed to light from both sides but water faces only one side of the root.
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When light falls on one side of the root but both sides are surrounded by water.
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When one side of the root faces water while the other side faces light.
Correct Answer
A. When one side of the root faces water while the other side faces light.Explanation
Phototropism is the growth response of plants towards light, while hydrotropism is the growth response towards water. When one side of the root faces water while the other side faces light, the root will exhibit both phototropism and hydrotropism simultaneously. The root will grow towards the water side due to hydrotropism and towards the light side due to phototropism, enhancing the hydrotropic response. This is because the presence of light on one side of the root stimulates the growth towards that side, while the presence of water on the other side attracts the root towards it.Rate this question:
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Jul 11, 2023Quiz Edited by
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Jul 28, 2019Quiz Created by
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