Carbohydrates and Lipids

Course Overview

• Course Title: Biology 189: Fundamentals for Life Sciences

• Topics Covered: Carbohydrates and Lipids

Learning Objectives

• Define essential terms:

  • Macromolecules: Large, complex molecules made of smaller parts called monomers.

  • Polymers: Made of repeating units (monomers).

  • Monomers: Simple building blocks of macromolecules.

• Explain the formation and breakdown of polymers:

  • Dehydration Synthesis: chemical reaction to form covalent bonds between monomers

    Hydrolysis: chemical reaction to break bonds and separate monomers

    

  Define and understand carbohydrates and their roles:

  • Three primary functions in living organisms:

    1. Energy source

    2. Short-term energy storage

    3. Structural support

• Classify types of monosaccharides:

  • Monosaccharides: Single sugar molecules, crucial in various biological processes.

  • Recognize differences between:

    • Pentoses (5-carbon sugars)

    • Hexoses (6-carbon sugars)

    • Aldoses (sugars with aldehyde groups)

    • Ketoses (sugars with ketone groups)

• Define glycosidic linkages and how monosaccharides join.

• Differentiate larger carbohydrate types:

  • Disaccharides: Two monosaccharides joined.

  • Oligosaccharides: Few monosaccharides (3 to 10 units).

  • Polysaccharides: Many monosaccharides (hundreds or thousands).

• Describe functions of key polysaccharides:

  • Starch: Energy storage in plants.

  • Glycogen: Energy storage in animal muscles and liver.

  • Cellulose: Provides structural support in plant cell walls.

  • Chitin: Found in arthropod exoskeletons and fungal cell walls.

• Define lipids and their functions:

  • Three major types of lipids:

    1. Triglycerides: Fats and oils for energy storage.

    2. Phospholipids: Key components of cell membranes.

    3. Steroids: Hormones and signaling molecules.

  • Distinguish between saturated, unsaturated, and trans fats.

Macromolecules Overview

• Macromolecules: Large and complex molecules made from smaller units.

• Polymers: Composed of repeating monomer units.

Polymer Formation and Breakdown

Dehydration Synthesis

• Definition: Chemical reaction forming covalent bonds between monomers, resulting in water production.

• Importance: Fundamental method of building macromolecules.

Hydrolysis

• Definition: Reaction that breaks covalent bonds between monomers by adding water.

• Application: Key process in digestion and metabolism for energy release.

Carbohydrates

Definition

• Composition: Macromolecules made up of carbon, hydrogen, and oxygen. (C,H,O)

• Functions:

  1. Source of energy

  2. Short-term energy storage.

  3. Structural support for cells

Monosaccharides

• Definition: Simplest form of carbohydrates (single sugar), composed of CnH2nOn.

• Variations: Differ based on carbon number and arrangement of functional groups (-H and -OH).

Types of Monosaccharides

• Pentoses: 5-carbon sugars (e.g., ribose).

  

  Hexoses: 6-carbon sugars (e.g., glucose, fructose, galactose).

  

  Aldose Characteristic: Sugars containing aldehyde group (e.g., glucose).

• Ketose Characteristic: Sugars containing ketone group (e.g., fructose).

Glycosidic Linkage

• Definition: Covalent bond formed between monosaccharides via a dehydration reaction.

• Types of Carbohydrates:

  • Disaccharides: Two monosaccharides

  • Oligosaccharides: 3 to 10 (usually)

  • Polysaccharides: Many monosaccharides made of hundreds or more

Key Polysaccharides

• Starch: Energy storage in plants; branched structure.

• Glycogen: Energy storage in animals, highly branched.

• Cellulose: is a polysaccharide is used for plant structure

• Chitin: Found in exoskeletons of arthropods and fungal cell walls.

Lipids

Overview

• Definition: Hydrophobic macromolecules primarily composed of C-H and C-C bonds, characterized by their nonpolar nature.

• Types of Lipids:

  1. Triglycerides: Consist of three fatty acids and glycerol for energy storage and insulation.

  2. Phospholipids: Major component of cell membranes, amphipathic (both hydrophobic and hydrophilic parts).

  3. Steroids: Structure consists of four fused rings, used in cell signaling (e.g., cholesterol, hormones).

Saturated and Unsaturated Fats

• Saturated Fats: Only single C-C bonds; solid at room temperature.

  • Maximum hydrogen bonding leads to tight packing.

• Unsaturated Fats: Contain one or more double bonds (kinks); liquid at room temperature due to loose packing.

• Trans Fats: Created by hydrogenation, converting unsaturated fats to saturated fats.

• Importance: Nutritional implications for health in dietary choices.

Functional Groups and Reactions

• Triglycerides: Formed by ester linkages between fatty acids and glycerol.

• Hydrolysis Reactions: Involved in breaking apart triglycerides for energy use.

Conclusion

• Understanding carbohydrates and lipids is essential in biology, impacting energy storage, structural integrity, and cellular functions. Knowledge about macromolecules provides a groundwork for exploring complex biological processes.