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General Knowledge Cluster27 Verified Questions
Plant Physiology GK Questions & Answers
Plant physiology encompasses the biochemical and biophysical mechanisms governing plant autotrophic nutrition, vascular fluid dynamics, and developmental regulation. Photosynthesis converts carbon dioxide and water into glucose and oxygen via light-dependent reactions in thylakoid membranes generating ATP and NADPH, followed by light-independent carbon fixation in the chloroplast stroma. In C3 plants, the enzyme RuBisCO (Ribulose-1,5-bisphosphate carboxylase-oxygenase) catalyzes the Calvin cycle producing 3-phosphoglycerate, whereas C4 plants (e.g., maize, sugarcane) utilize PEP carboxylase and Kranz anatomy to suppress photorespiration. Long-distance vascular transport relies on xylem tissue, comprising dead tracheids and vessels that transport water and dissolved inorganic ions upward under the Cohesion-Tension theory formulated by Henry Dixon and John Joly (1894), driven by stomatal transpiration pull. Phloem tissue, containing living sieve tube elements and nucleated companion cells, translocates photosynthesized sucrose bidirectionally via Ernst Munch's Pressure-Flow hypothesis. Phytohormones regulate morphogenesis: auxins (indole-3-acetic acid) promote apical dominance; gibberellins induce stem elongation and break seed dormancy; cytokinins promote cytokinesis; abscisic acid (ABA) acts as a stress hormone inducing stomatal closure; and ethylene gas stimulates climacteric fruit ripening.
High-yield conceptual summaries for competitive exams and rapid revision.
Photosynthesis converts carbon dioxide and water into glucose and oxygen through thylakoid light reactions and stromal Calvin cycle carbon fixation.
C4 plants utilize specialized Kranz leaf anatomy and PEP carboxylase to concentrate carbon dioxide, minimizing wasteful RuBisCO photorespiration.
Xylem conducts water and inorganic minerals unidirectionally from roots to shoots driven by the Dixon-Joly Cohesion-Tension transpiration pull.
Phloem translocates soluble carbohydrates bidirectionally through living sieve tube elements according to Munch's Pressure-Flow hypothesis.
Key phytohormones include growth promoters (auxins, gibberellins, cytokinins) alongside stress hormone abscisic acid and fruit-ripening ethylene gas.
Showing 25 Curated Questions27 Total in Bank
1ID: GK-GSCI-00483
easyBiological Principles & Living Systems
Which gas is primarily absorbed by terrestrial green plants during the daytime photosynthesis process?
Verified Explanation
During photosynthesis, plants take in carbon dioxide (CO2) from the atmosphere through stomata and water from soil to synthesize glucose, releasing oxygen as a byproduct.
2ID: GK-GSCI-00478
easyBiological Principles & Living Systems
What is the green pigment in plant chloroplasts that absorbs light energy during photosynthesis?
Verified Explanation
Chlorophyll is the primary photosynthetic pigment located in the thylakoid membranes of chloroplasts, absorbing blue and red light while reflecting green light.
3ID: GK-GSCI-00159
easyBiological Principles & Living Systems
Which green pigment present in chloroplasts is primarily responsible for capturing light energy during photosynthesis?
Verified Explanation
Chlorophyll is the green pigment in plant chloroplasts that absorbs light energy (predominantly in the blue and red regions of the spectrum) to drive photosynthesis.
4ID: GK-GSCI-00202
easyBiological Principles & Living Systems
Which gas is absorbed by green plants from the atmosphere during photosynthesis to produce carbohydrates?
Verified Explanation
During photosynthesis, green plants absorb carbon dioxide (CO2) through microscopic pores called stomata to synthesize glucose and other carbohydrates.
5ID: GK-GSCI-00258
easyBiological Principles & Living Systems
What green pigment in plants is essential for absorbing light during photosynthesis?
Verified Explanation
Chlorophyll is the primary green pigment in chloroplasts that absorbs blue and red wavelengths of light for photosynthesis.
6ID: GK-GSCI-00353
easyBiological Principles & Living Systems
Which green pigment in plant leaves absorbs light energy to drive the process of photosynthesis?
Verified Explanation
Chlorophyll, located in the thylakoid membranes of chloroplasts, absorbs light predominantly in the blue and red wavelengths while reflecting green light, facilitating photosynthesis.
7ID: GK-GSCI-00413
easyBiological Principles & Living Systems
Which plant cellular organelle is the primary site of photosynthesis?
Verified Explanation
Chloroplasts contain chlorophyll pigments and thylakoid membranes where light-dependent and Calvin cycle reactions of photosynthesis occur.
8ID: GK-GSCI-00538
easyBiological Principles & Living Systems
Which green pigment in plants is essential for capturing solar energy during photosynthesis?
Verified Explanation
Chlorophyll is the green pigment in chloroplasts that absorbs light energy (principally blue and red wavelengths) to drive photosynthesis.
9ID: GK-GSCI-00009
easyBiological Principles & Living Systems
Which pigment in plant leaves absorbs sunlight for photosynthesis, giving leaves their green color?
Verified Explanation
Chlorophyll a and b pigments inside chloroplasts absorb blue and red light while reflecting green light.
10ID: GK-GSCI-00057
easyBiological Principles
Which green pigment found inside chloroplasts absorbs sunlight to drive the process of photosynthesis in plants?
Verified Explanation
Chlorophyll molecules contain a central magnesium ion in a porphyrin ring, absorbing red and blue light while reflecting green.
11ID: GK-GSCI-00194
hardBiological Principles & Living Systems
In eukaryotic plant photosynthesis, the enzymatic light-independent dark reactions (Calvin-Benson cycle) occur specifically within which sub-chloroplast compartment?
Verified Explanation
While the light-dependent reactions occur in the thylakoid membranes to generate ATP and NADPH, the light-independent enzymatic fixation of CO2 (Calvin cycle mediated by RuBisCO) takes place in the fluid stroma.
12ID: GK-GSCI-00213
easyBiological Principles & Living Systems
Which green pigment located inside plant chloroplasts is primary in capturing solar energy for photosynthesis?
Verified Explanation
Chlorophyll a is the primary photosynthetic pigment in oxygenic photosynthetic organisms, absorbing blue and red light.
13ID: GK-GSCI-00598
easyBiological Principles & Living Systems
Which green pigment in autotrophic plants is essential for absorbing light energy during photosynthesis?
Verified Explanation
Chlorophyll is the primary photosynthetic pigment located in the thylakoid membranes of chloroplasts that absorbs blue and red wavelengths of solar light.
14ID: GK-OCEN-00223
mediumOcean Currents, Topography & Marine Ecology
Which ocean vertical pelagic zone extends from 200 metres down to 1,000 metres depth, where sunlight is too dim to support photosynthesis, leading fauna (like hatchetfish) to evolve ventral photophores for counterillumination camouflage?
Verified Explanation
The Mesopelagic zone (200 m to 1,000 m) receives faint downwelling blue sunlight insufficient for plant photosynthesis. Organisms residing here frequently possess large sensitive eyes and ventral light-emitting photophores that emit bioluminescent light matching downwelling surface light (counterillumination) to disguise their silhouettes from upward-looking predators.
15ID: GK-ENV-00009
easyEcosystems & Biodiversity
What is an organism that produces its own food through photosynthesis called in an ecological food chain?
Verified Explanation
Autotrophs (green plants, phytoplankton) synthesize organic molecules from inorganic carbon dioxide and sunlight.
16ID: GK-GSCI-00513
hardBiological Principles & Living Systems
In photosynthetic carbon assimilation (Calvin-Benson cycle), which key enzyme catalyzes the primary carboxylation of ribulose-1,5-bisphosphate?
Verified Explanation
RuBisCO is the primary enzyme of carbon fixation in the stroma of chloroplasts, catalyzing the reaction between CO2 and ribulose-1,5-bisphosphate to form two molecules of 3-phosphoglycerate.
17ID: GK-GSCI-00278
mediumBiological Principles & Living Systems
What type of symbiotic relationship is exhibited by lichens?
Verified Explanation
Lichens represent an obligate mutualistic relationship where the photobiont (algae or cyanobacteria) provides food via photosynthesis and the mycobiont (fungus) provides structure and moisture absorption.
18ID: GK-ENV-00151
easyEcosystems & Biodiversity
In an ecological food chain, organisms that produce organic nutrients from carbon dioxide and water using sunlight are called:
Verified Explanation
Autotrophs (primary producers), such as green plants, algae, and cyanobacteria, synthesize their own food via photosynthesis, forming the base of ecological food webs.
19ID: GK-ENV-00186
mediumEcosystems & Biodiversity
Mass coral bleaching occurs primarily when prolonged elevated sea surface temperatures induce reef-building scleractinian corals to expel which endosymbiotic photosynthetic dinoflagellates?
Verified Explanation
Under thermal stress, corals lose their intracellular zooxanthellae (which provide up to 90% of their metabolic energy via photosynthesis), exposing the white calcium carbonate skeleton.
20ID: GK-ENV-00204
easyEcosystems & Biodiversity
In an ecological food chain, organisms that produce their own organic nutrients from inorganic substances using sunlight are termed:
Verified Explanation
Primary producers (autotrophs), such as green plants, algae, and cyanobacteria, synthesize organic compounds from CO2 and water via photosynthesis at the first trophic level.
21ID: GK-ENV-00301
easyEcosystems & Biodiversity
What fundamental trophic level is formed by green plants and photosynthetic algae that produce organic biomass from sunlight?
Verified Explanation
Primary producers (autotrophs) form the first trophic level in all ecosystems, fixing solar energy into organic chemical energy via photosynthesis to support heterotrophic food webs.
22ID: GK-ENV-00471
easyEcosystems & Biodiversity
What is the primary source of all trophic energy entering the majority of terrestrial and aquatic ecosystems?
Verified Explanation
Solar energy captured by green plants, algae, and cyanobacteria via photosynthesis forms the trophic base (primary productivity) of nearly all ecosystems on Earth.
23ID: GK-ENV-00534
easyEcosystems & Biodiversity
What is the primary ecological process by which autotrophic plants convert inorganic carbon into organic biomass using sunlight?
Verified Explanation
Photosynthesis is the fundamental primary production mechanism where green plants and phytoplankton convert CO2 and water into glucose and oxygen using solar radiation.
24ID: GK-ENV-00594
easyEcosystems & Biodiversity
In an ecological food chain, organisms that produce organic biomass from inorganic carbon and sunlight are termed:
Verified Explanation
Primary producers (autotrophs, such as green plants, phytoplankton, and algae) synthesize carbohydrates from CO2 and water via photosynthesis, forming the foundational first trophic level.
25ID: GK-OCEN-00037
easyOcean Currents, Topography & Marine Ecology
Which microscopic photosynthetic organisms, including diatoms, dinoflagellates, and coccolithophores, form the primary producer base of marine food webs and produce ~50% of global oxygen?
Verified Explanation
Phytoplankton are single-celled drifting microscopic plants that drift in the sunlit euphotic zone of the oceans. Through photosynthesis, they consume carbon dioxide and produce approximately 50% of the oxygen on Earth.
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