Biochemistry 1 Lecture 3 PDF

# Adalel Alm College of Medical Sciences ## Department of Higher Education ### Course: Biochemistry 1 - Section: Fourth Section - Semester: Spring 2024-2025 - Lecture: Third Lecture ### Instructor: Moudah Talha Khojali Abbas ## Carbohydrates Chemistry - Carbohydrates Are Aldehyde or Ketone Derivat...

# Adalel Alm College of Medical Sciences ## Department of Higher Education ### Course: Biochemistry 1 - Section: Fourth Section - Semester: Spring 2024-2025 - Lecture: Third Lecture ### Instructor: Moudah Talha Khojali Abbas ## Carbohydrates Chemistry - Carbohydrates Are Aldehyde or Ketone Derivatives of Polyhydric Alcohols ### Polyhydric Alcohol - CH₂-OH - CH-OH - CH₂-OH ### Importance of Carbohydrates - Serve as Source of Energy e.g Glucose - They Form Structural Element in Animal and Plant Cells. eg.cellulose and Chitin ### Classifications of Carbohydrates - Carbohydrates Are Classified According to the Number of Sugar Units - Monosaccharides: Contain One Sugar Unit - Disaccharides: Contain Two Sugar Units - Oligosaccharides: 3-10 Sugar Units - Polysaccharides: Contain More Than 10 Sugar Units - Monosaccharides Are the Simplest Units of Carbohydrates; i.e., on Hydrolysis They Cannot Give a Simpler Form - General Formula of Monosaccharides is C_n(H₂O)_n ### Nomenclature of Mono - "Ose" Means Sugar - Aldoses: Monosaccharides Contain Aldehyde Group - Ketoses: Monosaccharides Contain Ketone Group ### Classification of Monosccharides - According to the Number of Carbon Atoms: - Triose: Mono Containing 3 Carbons - Tetrose: Containing 4 Carbon Atoms - Pentoses: Containing 5 Carbons - Hexoses: Containing 6 Carbons - Heptoses: Containing 7 Carbons - According to Functional Group: - Aldoses - Ketoses - According to Both Presence of Aldehyde or Ketone Group and Number of Carbon Atoms: - Aldotriose and Ketotriose - Aldotetrose and Ketotetrose - Aldopentose and Ketopentose - Aldohexose and Ketohexose ### Table 13-1. Classification of Important Sugars | Types | Aldoses | Ketoses | |---|---|---| | Trioses (C3H6O3) | Glycerose | Dihydroxyacetone | | Tetroses (C4H8O4) | Erythrose | Erythrulose | | Pentoses (C5H10O5) | Ribose | Ribulose | | Hexoses (C6H12O6) | Glucose | Fructose | ### Aldotrioses - CHO - H-C-OH - CH₂OH - D-Glycerose (D-Glyceraldehyde) ### Aldotetroses - CHO - H-C-OH - H-C-OH - CH₂OH - D-Erythrose ### Aldopentoses - CHO - HO-C-H - HO-C-H - H-C-OH - CH₂OH - D-Lyxose - CHO - H-C-OH - HO-C-H - H-C-OH - CH₂OH - D-Xylose - CHO - HO-C-H - H-C-OH - H-C-OH - CH₂OH - D-Arabinose - CHO - H-C-OH - H-C-OH - H-C-OH - CH₂OH - D-Ribose ### Aldohexoses - CHO - H-C-OH - HO-C-H - HO-C-H - H-C-OH - CH₂OH - D-Galactose - CHO - HO-C-H - H-C-OH - H-C-OH - H-C-OH - CH₂OH - D-Mannose - CHO - H-C-OH - HO-C-H - H-C-OH - H-C-OH - CH₂OH - D-Glucose ### Ketoses - CH₂OH - C=O - HO-C-H - H-C-OH - H-C-OH - CH₂OH - Dihydroxyacetone - CH₂OH - C=O - H-C-OH - H-C-OH - CH₂OH - D-Xulose - CH₂OH - C=O - HO-C-H - H-C-OH - CH₂OH - D-Ribulose - CH₂OH - C=O - HO-C-H - H-C-OH - CH₂OH - D-Fructose - CH₂OH - C=O - HO-C-H - H-C-OH - H-C-OH - CH₂OH - D-Sedoheptulose ### Ketotrioses - CH₂OH - C=O - CH₂OH - Dihydroxyacetone ### Ketopentoses - CH₂OH - C=O - H-C-OH - H-C-OH - CH₂OH - D-Ribulose ### Ketohexoses - CH₂OH - C=O - HO-C-H - H-C-OH - H-C-OH - CH₂OH - D-Fructose ### Ketoheptoses - CH₂OH - C=O - HO-C-H - H-C-OH - H-C-OH - H-C-OH - CH₂OH - D-Sedoheptulose ### Structures of Glucose - **Straight Chain Form** - ¹C=O - H²C-OH - HO³C-H - H⁴C-OH - H⁵C-OH - ⁶CH₂OH - **Formation of Hawthorn Projection** - HOCH₂ - - - - - - - - - - **Chair Form Structure** - - - - ### Physical Properties - All Monosaccharides Are Soluble in Water - All Monosaccharides Show the Property of Optical Activity ### Optical Activity - It Is the Ability of Substance to Rotate the Plane Polarized Light Either to Right or to Left in the Polariscope. - The Optical Activity Property Depends on the Asymmetric Carbon Atom in the Chemical Structure of the Substance ### Asymmetric Carbon Atoms - Is That Carbon Atom Which Is Attached to 4 Different Groups or Atoms ### Examples - - - - - - - - - - - ### N.B: - Any Substance Containing Asymmetric Carbon Atom Shows Two Properties: - Optical Activity - Optical Isomerism ### Isomerism - Compounds That Have the Same Molecular Formula but Differ in the Spatial Configuration. - **Examples** - A Substance Containing One Asymmetric Carbon Atom Has Two Isomers. - A Substance Containing 2 or More Asymmetric Carbon Atoms Can Exist in Numbers of Isomers = 2ⁿ. - N Is the Number of Carbon Atoms ### Types of Isomerisms - Enantiomers ( L & D Forms ) - Monosaccharides Are Classified into D and L Form According to the Position of -OH Attached to Carbon Atom Adjacent to Last CH₂OH. - Most of the Monosaccharides Occurring in Mammals Are of D Configuration ( Form ). - **Examples** - - HO - ²C-H H - ²C-OH - ³CH₂OH ³ CH₂OH - L-Glycerose D- Glycerose - (L-glyceraldehyde) (D-glyceraldehyde) - - - - - - HO - ⁵C-H H - ⁵C-OH - ⁶CH₂OH ⁶CH₂OH - L-Glucose D-Glucose - **Pyranose and Furanose Forms** - The Stable Ring Structures of Monosaccharides Are Similar to the Ring Structures of Either Pyran (a Six-membered Ring) or Furan (a Five-membered Ring). - **Anomers** - Are Isomers Obtained From the Change of Position of Hydroxyl Group Attached to the Anomeric Carbon. - **Anomeric Carbon** - Is the Carbon Atom Obtained From Active Carbonyl Sugar Group: - Carbon Number 1 in Aldoses - Carbon Number 2 in Ketoses - **Examples of Anomers** - - - - - - - - - - - -