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Questions and Answers
What are ergastic cell contents primarily composed of?
What are ergastic cell contents primarily composed of?
- Only carbohydrates and proteins
- Non-living substances (correct)
- Living cell structures
- Only primary metabolites
Which of the following best characterizes primary metabolites?
Which of the following best characterizes primary metabolites?
- Secondary byproducts of metabolism
- Not crucial for growth and reproduction
- Necessary for immediate plant survival (correct)
- Organically synthesized for defense
What distinguishes secondary metabolites from primary metabolites?
What distinguishes secondary metabolites from primary metabolites?
- They have other functions like defense (correct)
- They are essential for survival
- They directly participate in metabolic processes
- Their absence leads to plant death
Which of the following is NOT considered a primary metabolite?
Which of the following is NOT considered a primary metabolite?
How are carbohydrates defined chemically?
How are carbohydrates defined chemically?
Which category of carbohydrates contains more than 10 sugar units?
Which category of carbohydrates contains more than 10 sugar units?
What is the primary source of energy stored in plants?
What is the primary source of energy stored in plants?
What is one function of secondary metabolites?
What is one function of secondary metabolites?
What is the structural function of cellulose in plants?
What is the structural function of cellulose in plants?
Which statement about monosaccharides is true?
Which statement about monosaccharides is true?
What property distinguishes amylopectin from amylose?
What property distinguishes amylopectin from amylose?
Which test would best confirm the presence of starch?
Which test would best confirm the presence of starch?
What is a common medicinal use of starch?
What is a common medicinal use of starch?
Which of the following is NOT a type of starch grain noted for pharmaceutical interest?
Which of the following is NOT a type of starch grain noted for pharmaceutical interest?
What happens to starch when it comes into contact with iodine?
What happens to starch when it comes into contact with iodine?
What is the main component of ribose that is essential for coenzymes?
What is the main component of ribose that is essential for coenzymes?
What role does mucilage play in plant membranes?
What role does mucilage play in plant membranes?
Which of the following is a characteristic of pectin?
Which of the following is a characteristic of pectin?
What is dextrin primarily used for?
What is dextrin primarily used for?
How are polysaccharides classified?
How are polysaccharides classified?
Which statement about starch-derived drugs is true?
Which statement about starch-derived drugs is true?
What are aleurone grains primarily associated with in plants?
What are aleurone grains primarily associated with in plants?
What is a common use of mucilage in the pharmaceutical industry?
What is a common use of mucilage in the pharmaceutical industry?
Which type of proteins are primarily found in seeds?
Which type of proteins are primarily found in seeds?
Study Notes
Ergastic Cell Contents
- Non-living substances found within plant cells
- Can be identified via microscopy or chemical tests
- Present in the cytoplasm and vacuole
Primary and Secondary Metabolites
- Primary metabolites are essential for plant survival and involved in growth, development, and reproduction
- Examples include carbohydrates, proteins, and lipids
- Secondary metabolites aren't essential for plant survival, but play a role in defense (e.g., alkaloids, volatile oils, tannins)
Primary Metabolites
Carbohydrates
- Defined as compounds composed of carbon, hydrogen, and oxygen with a 2:1 ratio of hydrogen to oxygen
- Classified by the number of sugar units (monosaccharides, disaccharides, oligosaccharides, polysaccharides)
- Major roles in plants:
- Energy source (e.g., starch for storage)
- Structural function (e.g., cellulose in cell walls)
- Building blocks (e.g., ribose in coenzymes, deoxyribose in DNA)
Starch
- Polysaccharide composed of many glucose units
- Stored as starch grains, mainly consisting of amylose and amylopectin
- Amylose (unbranched, soluble) gives blue color with iodine
- Amylopectin (branched, insoluble) gives bluish black precipitate with iodine
Tests for Carbohydrates
- Iodine Test: Starch suspension turns dark bluish black
- Molisch's Test: Starch suspension with alcoholic α-naphthol, upon addition of concentrated H2SO4 on the test tube wall, forms a violet ring at the interface
Medicinal Uses of Starch
- Dusting powder (absorbs moisture, alleviates itching)
- Antidote for iodine poisoning
- Lubricant for surgeons' gloves
- Tablet disintegrant
- Suspending agent for barium meals (Radiography)
- Nutrient and demulcent properties
Other Polysaccharides
- Includes mucilage, gums, and pectin
Mucilage
- Viscous, sticky material that thickens membranes in plants.
- Forms colloidal solutions with water
- Medicinally used as:
- Demulcent (cough suppressant)
- Emollient
- Bulk laxative
Gums
- Viscous secretions from trees and shrubs
- Harden on drying and are soluble in water
- Used in pharmaceutical emulsions and suspensions
Pectin
- Purified carbohydrate obtained from citrus fruit rind (acid extraction)
- Source of dietary fiber
- Found in primary cell walls of terrestrial plants
- Food applications (gelling agent)
- Pharmacy applications:
- Suspending agent
- Antidiarrheal formulations
Drugs Derived from Starch
- Hetastarch (hydroxyethyl starch): Plasma expander
- Dextrin: Product of partial starch degradation, used in infant formulas, drug delivery
- Dextran: Plasma expander
Proteins
- Classified into:
- Structural proteins (cell membranes and cell walls)
- Storage proteins (seeds)
- Enzymes
- Plants store proteins as amorphous masses called aleurone grains, often containing crystalloids and globloids.
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Description
This quiz covers important concepts related to the contents of plant cells, focusing on ergastic substances and the distinction between primary and secondary metabolites. Learn about carbohydrates like starch and their vital roles in plant structure and energy storage. Test your understanding of these essential biological components.
