Plant Cell Metabolites Overview

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Questions and Answers

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?

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?

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?

Tannins Signup and view all the answers

How are carbohydrates defined chemically?

Compounds composed of C, H, and O with H and O in a 2:1 ratio Signup and view all the answers

Which category of carbohydrates contains more than 10 sugar units?

Polysaccharides Signup and view all the answers

What is the primary source of energy stored in plants?

Starch Signup and view all the answers

What is one function of secondary metabolites?

Acting as byproducts of metabolism Signup and view all the answers

What is the structural function of cellulose in plants?

Component of the cell wall Signup and view all the answers

Which statement about monosaccharides is true?

They are the simplest form of carbohydrates Signup and view all the answers

What property distinguishes amylopectin from amylose?

It has branched chains Signup and view all the answers

Which test would best confirm the presence of starch?

Iodine test Signup and view all the answers

What is a common medicinal use of starch?

As a lubricant for surgical gloves Signup and view all the answers

Which of the following is NOT a type of starch grain noted for pharmaceutical interest?

Barley Signup and view all the answers

What happens to starch when it comes into contact with iodine?

It produces a bluish-black precipitate Signup and view all the answers

What is the main component of ribose that is essential for coenzymes?

Monosaccharides Signup and view all the answers

What role does mucilage play in plant membranes?

Plays a protective role by thickening membranes Signup and view all the answers

Which of the following is a characteristic of pectin?

It can be extracted from the rind of citrus fruits Signup and view all the answers

What is dextrin primarily used for?

As a nutritional supplement in infant formulas Signup and view all the answers

How are polysaccharides classified?

Based on their structural roles and functions Signup and view all the answers

Which statement about starch-derived drugs is true?

Dextrin is a product of partial degradation of starch Signup and view all the answers

What are aleurone grains primarily associated with in plants?

Storage of proteins Signup and view all the answers

What is a common use of mucilage in the pharmaceutical industry?

In the preparation of emulsions and suspensions Signup and view all the answers

Which type of proteins are primarily found in seeds?

Storage proteins Signup and view all the answers

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.