Biology MCQs on Tropic and Nastic Movements in Plants
Explore the fascinating world of plant movements with our comprehensive guide on tropic and nastic responses! 🌱🔄 From the directional growth influenced by light, gravity, and water to the rapid, reversible reactions triggered by touch or external stimuli, delve into the intricate ways plants adapt to their environment. Discover the role of key plant hormones like auxin, abscisic acid, cytokinins, and more in orchestrating these movements. Uncover the secrets of nyctinasty, haptonastic responses, and the captivating dance of flowers opening and closing with the daily light-dark cycle. Join us on this botanical journey as we unravel the mechanisms behind plant adaptability and growth🌿✨✨ #PlantMovements #TropicResponses #NasticMovements #BotanyExploratio#PlantSciencee
Tropic Movements:
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What is the definition of tropic movements in plants?
- A) Rapid, reversible responses to external stimuli.
- B) Directional growth responses to external stimuli.
- C) Non-directional movements triggered by touch.
- D) Hormone-controlled responses to light.
Answer: B) Directional growth responses to external stimuli.
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Which of the following is an example of positive phototropism?
- A) Closing of flowers at night.
- B) Roots growing towards gravity.
- C) Sunflower stems bend towards the sun.
- D) Leaves fold in response to touch.
Answer: C) Sunflower stems bend towards the sun.
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What hormone is primarily involved in phototropism, causing bending towards the light source?
- A) Cytokinins
- B) Jasmonic acid
- C) Auxin
- D) Gibberellins
Answer: C) Auxin
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In geotropism, what does positive geotropism refer to?
- A) Growth towards light.
- B) Growth against gravity.
- C) Growth towards gravity (e.g., roots).
- D) Grow away from gravity.
Answer: C) Growth towards gravity (e.g., roots).
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Which tropic movement involves plant organs growing towards or away from water?
- A) Thigmotropism
- B) Hydrotropism
- C) Geotropism
- D) Chemotropism
Answer: B) Hydrotropism
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What is thigmotropism?
- A) Growth towards light.
- B) Growth against gravity.
- C) Growth in response to touch or physical contact.
- D) Growth towards or away from moisture.
Answer: C) Growth in response to touch or physical contact.
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Which hormone is involved in thigmotropism, responding to mechanical stimuli?
- A) Gibberellins
- B) Jasmonic acid and ethylene
- C) Auxin
- D) Cytokinins
Answer: B) Jasmonic acid and ethylene
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What is chemotropism?
- A) Growth towards light.
- B) Growth against gravity.
- C) Growth in response to touch.
- D) Growth in response to chemical stimuli.
Answer: D) Growth in response to chemical stimuli.
Nastic Movements:
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How are nastic movements different from tropic movements?
- (A))They are directional.
- B) They are non-directional.
- C) They are always hormone-controlled.
- D) They involve growth toward gravity.
Answer: B) They are non-directional.
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What is nyctinasty?
- A) Movement in response to touch.
- B) Movement in response to gravity.
- C) Opening and closing of plant organs in response to light and darkness.
- D) Rapid and reversible hormonal responses.
Answer: C) Opening and closing of plant organs in response to light and darkness.
- Which type of nyctinasty is associated with temperature changes?
- A) Photonasty
- B) Thermonasty
- C) Haptonastic Movement
- D) Seismonasty
Answer: B) Thermonasty
- What hormone is linked with circadian rhythms and is involved in nyctinastic movements?
- A) Jasmonic acid
- B) Gibberellins
- C) Phytochromes
- D) Cytokinins
Answer: C) Phytochromes
- Which plant exhibits haptonastic movement?
- A) Sunflower
- B) Mimosa pudica (sensitive plant)
- C) Daisy
- D) Chestnut Rose
Answer: B) Mimosa pudica (sensitive plant)
Hormonal Regulation:
- Which hormone is involved in coleoptile growth, allowing it to push through the soil?
- A) Jasmonic acid
- B) Gibberellins
- C) Auxin
- D) Ethylene
Answer: B) Gibberellins
- What is the role of auxin in geotropism?
- A) It promotes downward growth in roots.
- B) It promotes upward growth in shoots.
- C) It causes rapid movements in response to touch.
- D) It stimulates coleoptile growth.
Answer: A) It promotes downward growth in roots.
- Which hormone is involved in hydrotropism, responding to water concentrations?
- A) Jasmonic acid
- B) Auxin
- C) Cytokinins
- D) Abscisic acid (ABA)
Answer: D) Abscisic acid (ABA) and cytokinins.
Differences Between Tropic and Nastic Movements:
- What is a characteristic feature of tropic movements?
- A) Directional response to touch.
- B) non-directional growth.
- C) Rapid and reversible responses.
- D) hormone-independent control.
Answer: A) Directional response to touch.
- Which of the following is a feature of nastic movements?
- A) Hormone-controlled responses.
- B) Directional growth towards stimuli.
- C) Rapid and reversible non-directional responses.
- D) Response to gravity.
Answer: C) rapid and reversible non-directional responses.
- What is an example of thigmonasty?
- A) Opening and closing of flowers.
- B) Rapid closure of Venus flytrap leaves in response to touch.
- C) Growth towards light.
- D) Downward growth of roots.
Answer: B) Rapid closure of Venus flytrap leaves in response to touch.
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In which movement is the involvement of hormones less prominent?
- A) Tropic movements
- B) Nastic movements
- C) Both are equally hormone-dependent.
- D) Hormones are not involved in either.
Answer: B) Nastic movements
Example Questions:
-
What is an example of positive chemotropism?
- A) Phototropism in sunflowers
- B) Growth of pollen tubes towards ovules during fertilization.
- C) Nyctinasty in Morning Glory Flowers.
- D) Thigmotropism in Mimosa pudica.
Answer: B) Growth of pollen tubes towards ovules during fertilization.
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Which hormone is involved in the response to temperature changes in plants?
- A) Jasmonic acid
- B) Gibberellins
- C) Auxin
- D) Abscisic acid (ABA)
Answer: D) Abscisic acid (ABA)
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What is the role of gibberellins in coleoptile growth?
- A) Stimulating cell elongation
- B) Inducing rapid movements
- C) Promoting root growth
- D) Inhibiting shoot growth
Answer: A) Stimulating cell elongation
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Which plant organ is covered by a coleoptile?
- A) Roots
- B) Leaves
- C) Shoot tip
- D) Flower
Answer: C) Shoot tip
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What is the primary stimulus for thigmotropism in plants?
- A) Light
- B) Gravity
- C) Water
- D) Touch
Answer: D) Touch
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Which type of movement involves the opening and closing of flowers in response to daily light-dark cycles?
- A) Thigmonasty
- B) Phototropism
- C) Nyctinasty
- D) Hydrotropism
Answer: C) Nyctinasty
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What is the term for the bending of sunflower stems toward the sun during the day?
- A) Negative phototropism
- B) Thigmotropism
- C) Positive phototropism
- D) Chemotropism
Answer: C) Positive phototropism
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Which type of movement involves rapid changes mediated by electrical and calcium signals in response to touch?
- A) Nyctinasty
- B) Thigmonasty
- C) Phototropism
- D) Geotropism
Answer: B) Thigmonasty
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In tropic movements, what does the term "tropic" signify?
- A) Rapid
- B) Directional
- C) Non-directional
- D) Reversible
Answer: B) Directional
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What is the primary factor influencing the direction of growth in geotropism?
- A) Light
- B) Water
- C) Gravity
- D) Temperature
Answer: C) Gravity
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