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Questions and Answers
What is the name of the calcium indicator that uses a single fluorescent protein with different colors for distinguishing calcium signals in different compartments?
What is the name of the calcium indicator that uses a single fluorescent protein with different colors for distinguishing calcium signals in different compartments?
The calcium response from a caterpillar biting a leaf is localized to the bite site.
The calcium response from a caterpillar biting a leaf is localized to the bite site.
False (B)
What are two ways calcium signals can vary based on the stimulus?
What are two ways calcium signals can vary based on the stimulus?
Calcium signals can vary in their lag phase (time delay before the signal starts), rise time (how long it takes to reach its peak), total transient length, shape, and location within the cell.
The GCaMP indicator relies on the binding of calcium to ______ for generating light.
The GCaMP indicator relies on the binding of calcium to ______ for generating light.
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Match the following calcium indicator types with their primary components:
Match the following calcium indicator types with their primary components:
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Calcium sensor proteins can have enzymatic activity.
Calcium sensor proteins can have enzymatic activity.
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Which of the following is NOT a characteristic of calmodulin (CaM)?
Which of the following is NOT a characteristic of calmodulin (CaM)?
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Calcium sensor proteins undergo a ______ change upon binding calcium, exposing hydrophobic regions that interact with target proteins.
Calcium sensor proteins undergo a ______ change upon binding calcium, exposing hydrophobic regions that interact with target proteins.
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What are the two main types of calcium sensor proteins?
What are the two main types of calcium sensor proteins?
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Match the following calcium sensor proteins with their characteristics:
Match the following calcium sensor proteins with their characteristics:
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What is the primary function of calcium-dependent protein kinases (CDPKs)?
What is the primary function of calcium-dependent protein kinases (CDPKs)?
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Calmodulin-like proteins (CMLs) are only found in plants.
Calmodulin-like proteins (CMLs) are only found in plants.
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What is the significance of the variable sequence in CDPKs?
What is the significance of the variable sequence in CDPKs?
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Which of the following molecules is the intermediate in the IAM pathway?
Which of the following molecules is the intermediate in the IAM pathway?
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The IPA pathway is identical to the canonical pathway for auxin synthesis.
The IPA pathway is identical to the canonical pathway for auxin synthesis.
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What is the primary function of auxin conjugation?
What is the primary function of auxin conjugation?
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The ______ transport of auxins is directional and occurs from the shoot apex to the root apex.
The ______ transport of auxins is directional and occurs from the shoot apex to the root apex.
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Match the following auxin synthesis pathways with their corresponding intermediates:
Match the following auxin synthesis pathways with their corresponding intermediates:
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Which of the following is NOT a common method of auxin storage?
Which of the following is NOT a common method of auxin storage?
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Apolar auxin transport is a passive process that occurs through the xylem.
Apolar auxin transport is a passive process that occurs through the xylem.
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What is the significance of the tryptophan-independent auxin synthesis pathway?
What is the significance of the tryptophan-independent auxin synthesis pathway?
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Which of these is NOT a factor that regulates gibberellin metabolism?
Which of these is NOT a factor that regulates gibberellin metabolism?
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The hydroxylation pathway of gibberellin synthesis uses different enzymes than the non-hydroxylation pathway.
The hydroxylation pathway of gibberellin synthesis uses different enzymes than the non-hydroxylation pathway.
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What is the effect of high concentrations of active gibberellins on the expression of the GA20ox and GA3ox genes?
What is the effect of high concentrations of active gibberellins on the expression of the GA20ox and GA3ox genes?
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The ______ mutant is very tall because there is no inactivation of gibberellin.
The ______ mutant is very tall because there is no inactivation of gibberellin.
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Match the gibberellin-related enzymes with their corresponding functions:
Match the gibberellin-related enzymes with their corresponding functions:
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What is the final product of the non-hydroxylation pathway of gibberellin synthesis?
What is the final product of the non-hydroxylation pathway of gibberellin synthesis?
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Gibberellins are only produced in the shoot apex.
Gibberellins are only produced in the shoot apex.
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Describe the role of the GUS reporter gene in studying gibberellin synthesis.
Describe the role of the GUS reporter gene in studying gibberellin synthesis.
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What is the primary difference between cis and trans forms of cytokinins?
What is the primary difference between cis and trans forms of cytokinins?
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Cytokinins can be inactivated by the addition of sugar or phosphate groups.
Cytokinins can be inactivated by the addition of sugar or phosphate groups.
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What is the name of the enzyme that catalyzes the transfer of an isopentenylic group to adenine, leading to the formation of transzeatin?
What is the name of the enzyme that catalyzes the transfer of an isopentenylic group to adenine, leading to the formation of transzeatin?
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The uncontrolled growth of lateral buds due to cytokinin activity can lead to the development of a phenomenon known as ______, characterized by the formation of bundles of branches along the stem.
The uncontrolled growth of lateral buds due to cytokinin activity can lead to the development of a phenomenon known as ______, characterized by the formation of bundles of branches along the stem.
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Match the following processes with their effect on cytokinin activity:
Match the following processes with their effect on cytokinin activity:
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Which of the following is NOT a common site of cytokinin production in plants?
Which of the following is NOT a common site of cytokinin production in plants?
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Pathogenic bacteria and fungi can produce cytokinins that affect plant growth.
Pathogenic bacteria and fungi can produce cytokinins that affect plant growth.
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Name a bacterial species that produces cytokinins and causes the formation of crown galls on plants.
Name a bacterial species that produces cytokinins and causes the formation of crown galls on plants.
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Ethylene, a gaseous plant hormone, is synthesized from the precursor molecule ______ through a series of enzymatic steps.
Ethylene, a gaseous plant hormone, is synthesized from the precursor molecule ______ through a series of enzymatic steps.
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Which of the following is NOT a characteristic of the triple response exhibited by plants treated with ethylene?
Which of the following is NOT a characteristic of the triple response exhibited by plants treated with ethylene?
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What is the name of the chemical used to mimic the effects of ethylene in plants?
What is the name of the chemical used to mimic the effects of ethylene in plants?
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Ethylene is only produced by ripening fruit, not by other parts of the plant.
Ethylene is only produced by ripening fruit, not by other parts of the plant.
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Match the following enzymes involved in ethylene biosynthesis with their corresponding functions:
Match the following enzymes involved in ethylene biosynthesis with their corresponding functions:
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Which of these is the direct precursor to ethylene biosynthesis?
Which of these is the direct precursor to ethylene biosynthesis?
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Briefly describe how ethylene was discovered as a plant hormone.
Briefly describe how ethylene was discovered as a plant hormone.
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Ethylene is very effective in promoting plant growth at high concentrations.
Ethylene is very effective in promoting plant growth at high concentrations.
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Study Notes
Calcium-Mediated Signal Transduction in Plants
- Calcium is a crucial intracellular messenger, playing a key role in plant signal transduction in response to both biotic and abiotic stimuli.
- Signals can be physical (e.g., temperature, light, touch) or chemical (e.g., pathogens, symbionts).
- Calcium signals trigger physiological responses like defense mechanisms or adaptation strategies.
- Changes in cytosolic calcium concentration, usually an increase, are the primary triggers for various physiological responses.
Calcium Homeostasis and Signal Transduction
- Resting cytosolic calcium concentration is low (10−7 M) but increases dramatically in response to stimuli (0.5-5µM).
- Apoplastic calcium concentration is high (10−3 M).
- Organelles like the vacuole store significant calcium (e.g., 80mM).
- Membrane proteins, including channels and pumps, maintain calcium homeostasis, transporting calcium into and out of the cytosol.
Calcium Transporters and Channels
- Calcium permeable channels, which don't use energy, allow calcium movement along its concentration gradient.
- Voltage-gated, mechanosensitive, and ligand-gated channels are different types of calcium channels.
- Active calcium transporters, powered by ATP, regulate calcium levels against the gradient, in the plasma membrane, ER, vacuole, and nuclear envelope.
- Calcium pumps are secondary transporters that use the energy from other ions to move calcium against the gradient
Methods to Measure Calcium
- Fluorescent dyes (e.g., Calcium Green, Fluo-3, Indo-1, Fura-2) change fluorescence intensity in response to calcium.
- Protein-based calcium indicators (e.g., Aequorin, Cameleon) convert calcium binding into light emission.
- GECIs (genetically encoded calcium indicators), a newer technology, allow direct observation of calcium in living cells.
Protein Targeting
- Proteins are specifically targeted to different cellular compartments (e.g., cytosol, vacuoles, mitochondria) to execute specialized functions.
- Targeting sequences (e.g., signal peptides, transit peptides) direct proteins to designated destinations within the cell.
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Description
Test your knowledge on calcium signaling and the different calcium indicators used in research. This quiz covers various aspects including the properties of calcium sensor proteins and their functions. Explore the fascinating mechanisms of how calcium signals can vary and the role of calmodulin in cellular processes.
