Study Notes for KMJ12203 Introduction to Biological and Chemical Science Principles

KMJ12203 Introduction to Biological and Chemical Science Principles

  • Instructor: Assoc. Prof. Dr. Khairul Farihan Kasim

  • Institution: Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis

Chapter 2: Cell Structure and Function

  • Overview:

    • Discusses the properties of water as a biochemical solvent.

    • Examination of the roles of amino acids, proteins, carbohydrates, lipids, and nucleic acids in cellular construction.

    • CO1: Explores the ability to apply biological basics, enzymes, and cell structure and functions (PO1).

Families of Biomolecules

  1. Carbohydrates

  1. Lipids

  1. Amino Acids

  1. Proteins and Enzymes

Carbohydrates

Definition of Carbohydrates:

  • Derived from: General formula [C(H₂O)]ₙ, often perceived as "hydrates of carbon."

  • Term Relations:

    • Carbohydrate and saccharide closely relate, with “saccharide” originating from words meaning sugar across languages:

    • Sanskrit: sarkara

    • Greek: sakcharon

    • Latin: saccharum

Importance of Carbohydrates

  • Widely distributed in nature.

  • Act as key intermediates in metabolism (e.g., sugars).

  • Serve as structural components in plants (e.g., cellulose).

  • Central to industrial products (e.g., paper, fibers).

  • Key in food sources (e.g., sugar, flour, vegetables, fiber).

Chemical Composition

  • Carbohydrates: Polyhydroxy aldehydes or ketones, or compounds yielding such derivatives upon hydrolysis.

Types of Carbohydrates

  • Monosaccharide: Simplest carbohydrates containing one unit (e.g., glucose).

  • Disaccharide: Contains two monosaccharides (e.g., sucrose, lactose).

  • Polysaccharide: Composed of more than 10 sugar units; high molecular weight, and often insoluble.

Classification of Carbohydrates

  • 1. Monosaccharides

  • 2. Oligosaccharides (2-10 monosaccharides).

  • 3. Polysaccharides (many sugar units).

Monosaccharides

  • Classification by Number of Carbons:

    • Trioses (3)

    • Tetroses (4)

    • Pentoses (5)

    • Hexoses (6)

    • Heptoses (7)

Examples

  • Trioses: Glyceraldehydes, Dihydroxyacetone

  • Tetroses: Erythrose, Erythrulose, Ribulose

  • Pentoses: Ribose, Xylose, Xylulose

  • Hexoses: Glucose, Fructose, Galactose

  • Heptoses: Glucoheptose, Sedoheptulose

Disaccharides

  • Example Types:

    • Lactose: Glucose + Galactose

    • Maltose: Glucose + Glucose

    • Sucrose: Glucose + Fructose

Properties of Disaccharides

  • Common Table Sugar:

    • Sucrose is a non-reducing disaccharide and contributes calories to the diet.

    • Contains glucose and fructose linked via an α-(1-2) glycosidic linkage.

    • Hydrolyzed by enzyme Sucrase (Invertase).

Oligosaccharides

  • Composed of 2-10 monosaccharide residues linked by glycosidic bonds.

  • General formula: C(H₂O)ₙ₋₁.

Functions

  • Stimulate growth of certain bacteria, increase resistance to pathogens, primary component in prebiotic food products.

Polysaccharides

  • Comprises many units; classified as glycans, either linear or branched.

  • Not sweet and do not exhibit aldehyde or ketone properties.

Examples of Polysaccharides

  • Starch:

    • Reserve carbohydrate in plants (e.g., potatoes).

    • Composed of D-glucose units linked by α-glycosidic bonds. Contains 15-20% amylose and 80-85% amylopectin.

  • Glycogen:

    • Major storage form in animals, referred to as animal starch, found primarily in the liver and muscles.

  • Cellulose:

    • Major component of plant cell walls; unbranched polymer of glucose with β-(1-4) glycosidic linkages, indigestible by humans, providing dietary fiber.

Chemical Properties of Monosaccharides

  • Key Reactions:

    • Furfural Formation: Sugars treated with strong acids (e.g., H₂SO₄) to form furfural derivatives, utilized under tests like Molisch's test.

    • Enolization/Tautomerization: Glucose in alkaline solutions yields D-fructose and D-mannose; undergo tautomerization to form enediols, which are capable of reducing.

    • Oxidation: Leads to monobasic aldonic acids, dibasic saccharic acids, or monobasic uronic acids, depending on reaction conditions.

Mutarotation

  • Changes in specific rotations of sugars (e.g., D-glucose) when alpha and beta anomers dissolve over time reaching a specific intermediate value.

Glycoside Formation

  • Resulting from interactions between hydroxyl groups, leading to O-glycosidic and N-glycosidic bonds, with physiological importance in drugs and treatments.

Conclusion

  • Overview of carbohydrates covers definitions, classifications, chemical properties, and their implications in nutrition and industry.

  • Emphasis on biological significance and the biochemical roles they play across various applications.