Terpenes and Their Biosynthesis
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Questions and Answers

What effect does ROS (reactive oxygen species) have on the plasma membrane?

  • It enhances membrane permeability.
  • It can lead to lipid peroxidation. (correct)
  • It strengthens membrane function.
  • It protects cells from osmotic stress.

    • Which of the following is NOT considered a compatible solute?

  • Trehalose
  • Pinitol
  • Sodium chloride (correct)
  • Glycerol

    • How do compatible solutes help maintain cellular homeostasis?

  • By scavenging reactive oxygen species. (correct)
  • By increasing cellular metabolism.
  • By promoting lipid peroxidation.
  • By inducing osmotic stress.

    • What triggers the synthesis of compatible solutes?

    <p>Stress conditions</p> Signup and view all the answers

    Which of the following is a nitrogen-containing compatible solute?

    <p>Proline</p> Signup and view all the answers

    What is the role of compatible solutes produced by microbial communities in plant tissues?

    <p>To protect against oxidative damage.</p> Signup and view all the answers

    Which compound is an example of a polyol used as a compatible solute?

    <p>Mannitol</p> Signup and view all the answers

    Which of the following statements about ROS production is false?

    <p>It is beneficial to microbial communities.</p> Signup and view all the answers

    What is the primary effect of Hypoglycin A on energy production?

    <p>It halts ATP production.</p> Signup and view all the answers

    What is a consequence of anaerobic energy production?

    <p>Lactic acid buildup.</p> Signup and view all the answers

    How does cyanide affect cellular respiration?

    <p>It blocks aerobic respiration.</p> Signup and view all the answers

    What role do lectins play in immune response?

    <p>Enhance phagocytic activity.</p> Signup and view all the answers

    Which of the following describes the relationship between lectins and cytokine release?

    <p>Lectins activate cells to release pro-inflammatory cytokines.</p> Signup and view all the answers

    What happens to cells when hypoxia occurs?

    <p>Cells die due to lack of oxygen.</p> Signup and view all the answers

    What is a function of nitric oxide production stimulated by lectins?

    <p>To regulate immune responses.</p> Signup and view all the answers

    Which iron form does oxygen bind to in cytochrome oxidase?

    <p>Fe2+</p> Signup and view all the answers

    What is the primary role of isopentenyl pyrophosphate (IPP) in terpene biosynthesis?

    <p>To serve as a starting molecule for larger terpenes</p> Signup and view all the answers

    Which terpene is most commonly associated with a citrus aroma?

    <p>Limonene</p> Signup and view all the answers

    Which of the following statements about isoprene units is correct?

    <p>Isoprene units are required for the biosynthesis of carotenoids.</p> Signup and view all the answers

    What is the function of terpene synthase in terpene biosynthesis?

    <p>To catalyze the synthesis of terpenes</p> Signup and view all the answers

    Which terpene is commonly found in hops, mango, and lemongrass?

    <p>Myrcene</p> Signup and view all the answers

    What reaction does isopentenyl pyrophosphate isomerase catalyze?

    <p>Isomerization between IPP and DMAPP</p> Signup and view all the answers

    What is the main characteristic of terpenes derived from isoprene?

    <p>They are classified based on their chain length.</p> Signup and view all the answers

    Which terpene is associated with having a peppery scent and is often found in black pepper, cloves, and cinnamon?

    <p>Caryophyllene</p> Signup and view all the answers

    What is the primary action of Taxol as mentioned?

    <p>Block cancer cell growth</p> Signup and view all the answers

    Which plant is known for its poisonous compound Grayanotoxin?

    <p>Rhododendron</p> Signup and view all the answers

    Which statement correctly describes the use of Forskolin?

    <p>Employed in treating glaucoma</p> Signup and view all the answers

    What characterizes the compound Abietadiene?

    <p>Phytoalexin found in grand fir</p> Signup and view all the answers

    How do cardenolides affect the body?

    <p>Inhibit Na/K-ATPases</p> Signup and view all the answers

    Which of the following is a characteristic of Digoxin?

    <p>Aglycone moiety of digitoxin</p> Signup and view all the answers

    What is a common usage for the compound Gibberelin A1?

    <p>Plant growth regulator</p> Signup and view all the answers

    Which of these insects is known to feed on cardenolide-rich plants?

    <p>Monarch butterfly</p> Signup and view all the answers

    What is the main function of the compound Sitosterol?

    <p>Acts as a plant sterol</p> Signup and view all the answers

    What is a known risk associated with Abietadiene?

    <p>Toxicity through skin absorption</p> Signup and view all the answers

    What role do compatible solutes play in cells during oxidative stress?

    <p>They enhance the cellular structures and scavenge reactive oxygen species.</p> Signup and view all the answers

    Which of the following is NOT a function of phytohormones?

    <p>Promoting detoxification of free radicals</p> Signup and view all the answers

    Which compatible solute is specifically mentioned as helping to protect the photosynthetic machinery?

    <p>Glycine betaine</p> Signup and view all the answers

    What is one of the main consequences of increasing ionic strength in microbial cells?

    <p>Disruption of macromolecule stability.</p> Signup and view all the answers

    How do compatible solutes maintain cellular pH?

    <p>By stabilizing cellular structures and processes.</p> Signup and view all the answers

    Which of the following does not represent a role of reactive oxygen species?

    <p>Enhancing photosynthesis.</p> Signup and view all the answers

    In what environmental conditions do compatible solutes like proline become particularly important?

    <p>Drought and high light conditions.</p> Signup and view all the answers

    Which of these is a characteristic of auxin, a type of phytohormone?

    <p>Promotes root elongation.</p> Signup and view all the answers

    Study Notes

    Terpenes

    • Terpenes are organic compounds made from isoprene units, which combine to form larger chains.
    • IPP (isopentenyl pyrophosphate) and DMAPP (dimethylallyl pyrophosphate) are isomeres of each other, meaning they have the same chemical formula but different arrangements of atoms.
    • IPP isomerase catalyzes the isomerization of IPP to DMAPP and vice versa.
    • Common terpenes include:
      • Myrcene (found in hops, mango, lemongrass)
      • Pinene (found in needles, rosemary, basil, dill)
      • Caryophyllene (found in black pepper, cloves, cinnamon)
      • Limonene (found in fruits rinds, rosemary, juniper, peppermint)
      • Terpinolene (found in nutmeg, tea tree, cumin, lilacs)

    Terpene Biosynthesis

    • Terpenes are biosynthesized through a series of enzymatic reactions, starting with IPP and DMAPP.
    • The length of the terpene chain determines its classification:
      • Hemiterpenes (C5H8) - Isoprene is the only hemiterpene
      • Monoterpenes (C10H16) - GPP (geranyl pyrophosphate)
      • Sesquiterpenes (C15H24) - FPP (farnesyl pyrophosphate)
      • Diterpenes (C20H32) - GGPP (geranylgeranyl pyrophosphate)
      • Triterpenes (C30H48)
      • Tetraterpenes (C40H64) - Carotenoids
    • Terpene synthase catalyzes the formation of these structures.

    Plant Defense Compounds

    • Taxol: Antimitotic agent used to treat cancer by blocking cancer cell growth.
    • Forskolin: Insecticidal, anti-feedent properties, and treatment for glaucoma.
    • Abietadiene: Phytoalexin found in resin of grand fir (Abies grandis), protecting against wood-degrading fungi.
    • Grayanotoxin: Poison present in rhododendron.
    • Gibberelin A1: Plant growth regulator.

    Cardenolides

    • Type of steroids in the saponin family.
    • Active against mammal herbivores.
    • Bitter-tasting and very toxic.
    • Examples:
      • Ouabain: Plant derived toxic compound, traditionally used as arrow poison.
      • Acokanthera schimperi: Contains cardiac glycoside.
    • Monarch caterpillars and grasshopper (Poekilocerus bufonius) feed on milkweed plants containing cardenolides, storing them to deter predators.

    Hypoglycin A

    • Non-proteinogenic amino acid.
    • Acts as a phytotoxin and plant metabolite.
    • Toxic if ingested, producing cellular hypoxia by binding to ferric iron in the cytochrome oxidase system.
    • Cyanide blocks aerobic respiration by binding to the same iron, preventing oxygen from binding and halting energy production.
    • Cellular hypoxia leads to cell death.

    Compatible Solutes

    • Plant-derived compounds that help protect cells from stress.
    • Function as:
      • Osmoprotectants: Protect cellular structures by interacting with membranes, proteins, and other molecules.
      • Reactive Oxygen Species (ROS) scavengers: Protect against oxidative damage and maintain cellular homeostasis.
    • Examples:
      • Polyols (mannitol, pinitol, sorbitol, trehalose)
      • Carbohydrates (sucrose)
      • Nitrogen-containing compounds (amino acids like proline, amides, quaternary ammonium compounds like glycine betaine)

    Plant Lectins

    • Bind to carbohydrate structures on immune cells, triggering intracellular signaling.
    • Enhance phagocytic activity by facilitating the recognition of pathogens or dead cells.
    • Activate immune cells to release pro-inflammatory cytokines (TNF-α, IL-6, IL-1β).
    • Stimulate nitric oxide production via iNOS in macrophages, helping to destroy pathogens and regulate immune responses.

    Phytohormones

    • Chemical messengers produced by plants that regulate various cellular activities including:
      • Cellular division
      • Elongation
      • Differentiation
      • Pattern formation
      • Organigenesis
      • Reproduction
      • Sex determination
      • Responses to biotic and abiotic factors
    • Examples:
      • Auxin
      • Gibberellins
      • Cytokinins
      • Abscisic acid
      • Ethylene
      • Brassinosteroids
      • Jasmonates
      • Salicylic acid

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    Description

    Explore the fascinating world of terpenes, organic compounds pivotal in various plants. This quiz covers their structures, biosynthesis, and common types found in nature, such as Myrcene and Limonene. Test your knowledge on isoprene units and the enzymatic processes that form these compounds.

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