Plant Metabolism and Cell Contents
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Questions and Answers

What is the primary role of carbohydrates in plant growth and metabolism?

  • To serve as a source of energy (correct)
  • To act as signaling molecules
  • To provide structural support
  • To facilitate nutrient absorption
  • Which carbohydrate is primarily responsible for providing immediate energy to plants?

  • Cellulose
  • Ribose
  • Starch
  • Monosaccharides (correct)
  • How is starch primarily stored in plants?

  • As cellulose fibers
  • As simple sugars dissolved in water
  • As starch grains (correct)
  • As protein complexes
  • What distinguishes amylopectin from amylose in terms of structure?

    <p>Amylopectin is branched, while amylose is unbranched.</p> Signup and view all the answers

    What color indicates a positive iodine test for starch?

    <p>Bluish black</p> Signup and view all the answers

    Which of the following is NOT a medicinal use of starch?

    <p>Enhancing muscle growth</p> Signup and view all the answers

    What property of amylose allows it to dissolve in water?

    <p>It is an unbranched chain.</p> Signup and view all the answers

    Which starch is primarily utilized as a suspending agent for barium meals in radiography?

    <p>Potato starch</p> Signup and view all the answers

    What are ergastic cell contents primarily composed of?

    <p>Non-living substances</p> Signup and view all the answers

    Which type of metabolites are essential for plant survival?

    <p>Primary metabolites</p> Signup and view all the answers

    What is the main role of secondary metabolites in plants?

    <p>They have roles such as defense and by-products of metabolism</p> Signup and view all the answers

    Which of the following compounds are classified as primary metabolites?

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

    How are carbohydrates characterized in terms of their elemental composition?

    <p>Carbon, hydrogen, and oxygen with a ratio of 2:1 for H and O</p> Signup and view all the answers

    Which of the following is a type of carbohydrate made of a single sugar unit?

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

    Which carbohydrate derivative is classified as a secondary metabolite?

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

    What distinguishes secondary metabolites from primary metabolites in terms of necessity for survival?

    <p>Absence of secondary metabolites does not result in immediate death</p> Signup and view all the answers

    What substance plays a protective role by thickening membranes in plants?

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

    Which of the following substances is classified as a polysaccharide and has medical uses?

    <p>All of the above</p> Signup and view all the answers

    Pectin is primarily obtained from which part of plants?

    <p>Rind of citrus fruits</p> Signup and view all the answers

    What function does pectin serve in the food industry?

    <p>Gelling agent</p> Signup and view all the answers

    Which drug derived from starch is specifically noted for its use in plasma expansion?

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

    What are aleurone grains primarily composed of within plant cells?

    <p>Crystalloid and globoid</p> Signup and view all the answers

    Which of the following best describes the role of mucilage in plants?

    <p>Forms colloidal solutions with water</p> Signup and view all the answers

    Which polysaccharide is used as a suspending agent in pharmaceuticals?

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

    Study Notes

    Ergastic Cell Contents

    • Non-living substances present in the cell.
    • Can be identified by microscopic examination or chemical and physical tests.
    • Found in cytoplasm and vacuole.

    Primary Metabolites

    • Essential for plant survival
    • Organic compounds involved in growth, development, and reproduction of the organism
    • Examples include carbohydrates, proteins, lipids
    • Absence of primary metabolites would result in immediate death.

    Secondary Metabolites

    • Not essential for plant survival.
    • Often referred to as byproducts of metabolism.
    • Examples include alkaloids, volatile oils, tannins, flavonoids.
    • Play roles in functions like defense.

    Carbohydrates

    • Composed of carbon, hydrogen, and oxygen
    • Carbon and hydrogen are present in the ratio 2:1, like that of water.
    • Classified by number of sugar units:
      • Monosaccharides (e.g. glucose)
      • Disaccharides (e.g. sucrose)
      • Oligosaccharides
      • Polysaccharides (e.g. starch, cellulose)

    Carbohydrates Role in Plants

    • Source of energy: Energy can be stored as starch (storage polysaccharide)
    • Structural Function: Example is cellulose in the plant cell wall
    • Building blocks: The 5-carbon monosaccharide ribose is a component of coenzymes and the backbone of RNA. Deoxyribose is a component of DNA.

    Starch

    • Polysaccharide formed of many glucose units
    • Source of energy
    • Stored in the form of starch grains
    • Starch granules are composed of amylose and amylopectin

    Amylose vs Amylopectin

    • Amylose: Unbranched chain of glucose units, soluble in water, gives blue color with iodine
    • Amylopectin: Branched chain of glucose units, insoluble in water, gives bluish black precipitate with iodine

    Starch Tests

    • General test for carbohydrates: Iodine test: Suspension of starch gives a dark bluish black color
    • Molisch's test: Suspension of starch and alcoholic α-naphthol gives violet ring at the interface upon addition of concentrated H2SO4.

    Medicinal Uses of Starch

    • Topically as dusting powder
    • Antidote for iodine poisoning
    • Lubricant for surgeons’ gloves
    • Tablet disintegrant
    • Suspending agent for barium meals
    • Nutrient and demulcent properties

    Important Starches

    • Potato starch
    • Maize starch
    • Wheat starch
    • Rice starch

    Starch Grain Features

    • Each grain has a hilum, the point of origin of starch deposition.
    • Starch is deposited in layers around the hilum.
    • Hilum can be located in the center or periphery.

    Other Polysaccharides: Mucilage and Gums

    • Mucilage: Viscous sticky material

    • Plays a protective role in membranes, forming colloidal solution in water.

    • Used as demulcent, emollient, and bulk laxatives

    • Gives red color with ruthenium red

    • Gums: Viscous secretion of trees and shrubs.

    • Hardens on drying but is soluble in water.

    • Used in pharmaceutical industry in the preparation of emulsions and suspensions.

    • Classified as polysaccharides or salts of polysaccharides

    Pectin

    • Purified carbohydrate obtained from the rind of citrus fruits.
    • Source of dietary fiber.
    • Structural polysaccharide in plant cell walls.
    • Used in food as a gelling agent.
    • Used in pharmacy as:
      • suspending agent
      • in antidiarrheal formulations

    Drugs Derived from Starch

    • Hetastarch (hydroxyethyl starch): Plasma expander
    • Dextrin: Product of partial degradation of starch, used in infant formulas for nutrition, drug delivery, oral disintegrating films
    • Dextran: Plasma expander

    Proteins

    • Classified into:

      • Structural proteins in the cell membrane and cell wall
      • Storage proteins, mostly in seeds
      • Enzymes
    • In plants, proteins are stored as amorphous mass called aleurone grains, often containing a crystalloid and a globoid.

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    Medicinal Plants Lecture 3 PDF

    Description

    Explore the fascinating world of plant cell composition and metabolism through this quiz. Delve into the differences between ergastic cell contents, primary and secondary metabolites, and carbohydrates. Test your understanding of the vital substances that contribute to plant life and their functions.

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