CHM360 Chapter - 9.2 & 13

Chapter 9: Biochemistry - Glycolysis and Carbohydrates

9.1 Overview

• Focus on metabolic regulation of glycolysis.

• Key topics include structure and function of carbohydrates, nucleic acids, and lipids.

9.2 Structures of Simple Sugars

Monosaccharides

• Definition: Single sugars, either aldoses (containing an aldehyde) or ketoses (containing a ketone).

  • Examples:

    • Glucose: a polyhydroxyaldehyde

    • Fructose: a polyhydroxyketone

  • Typically sweet, found in fruits and vegetables.

9.3 Drawing Monosaccharides

• Fischer Projections: Commonly used to represent chiral carbohydrates.

Key Definitions

• Enantiomers: Stereoisomers that are non-superimposable mirror images (e.g., D and L sugars).

• Diastereomers: Stereoisomers that are not mirror images and have different physical properties.

• Epimers: Sugars differing in configuration at only one chiral carbon (e.g., D-glucose vs. D-galactose).

9.4 Glycosidic Bonds and Disaccharides

• Disaccharides: Formed by two monosaccharides linked by an O-glycosidic bond through a condensation reaction.

• Common disaccharides include:

  • Lactose

  • Sucrose

  • Trehalose

9.5 Polysaccharides

• Definition: Long chains of monosaccharide units; can be homopolymers or heteropolymers.

• Starch: Used by plants to store glucose; contains amylose and amylopectin.

• Glycogen: Animal storage form of glucose, more branched than starch.

• Cellulose: Structural component of plant cell walls (β-1,4 glycosidic bonds).

  • Provides rigidity due to extensive hydrogen bonding.

9.6 Carbohydrate Functions

• Glycoconjugates: Include glycoproteins (protein emphasis) and proteoglycans (carbohydrate emphasis), playing roles in cellular recognition and signaling.

9.7 Reducing Sugars

• Definition: Carbohydrates that can reduce oxidizing agents (commonly aldoses).

• Their ability to react with oxidizing agents categorizes carbohydrates into reducing and non-reducing categories.

9.8 Structural Functions

• Chitin: A structural carbohydrate in the exoskeletons of arthropods and cell walls of fungi.

• Functions of Glycoconjugates: Serve in cell signaling, immune response, and adhesion processes.

9.9 Glycobiology

• Study of glycan structure and function with emphasis on:

  • Monosaccharide transport and biosynthesis

  • Protein binding activities and regulatory functions in cellular environments.

Chapter 13: Carbohydrate Structure and Function

13.1 Importance of Carbohydrates

• Most abundant biomolecules:

  • Composed of carbon, hydrogen, and oxygen.

  • Classified as:

    • Simple sugars

    • Polysaccharides

    • Glycoconjugates

13.2 Functions of Glycoconjugates

• Glycoproteins: Play roles in cell signaling and structural support within extracellular matrices.

• Proteoglycans: Regulate cellular activities, maintain tissue structure, and facilitate cell migration.

• Contain glycosaminoglycans.

13.3 Blood Groups

• Blood group classification linked to specific glycoproteins and glycolipids.

  • Determine compatibility for blood transfusions.

Study Tips

• Understand the structural features of carbohydrates to grasp their biological roles.

• Review glycosidic bond formation during carbohydrate biosynthesis as it emphasizes metabolic pathways.

• Familiarize yourself with the specific functions and classifications of polysaccharides and glycoconjugates in living organisms.

The content emphasizes structural details and functional roles of carbohydrates, including metabolism and interconversion processes. Keep the focus on understanding the relationships and differences between sugars and their biological significance.