Chapter 3: Proteins, Carbohydrates, and Lipids BIO 213

Definitions: carbohydrate, monosaccharide, disaccharide, oligosaccharide, polysaccharide, sugar, starch, cellulose, glycogen, lipid, fatty acid, triglyceride, glycosidic linkage, ester linkage, steroids, carotenoids, wax, phospholipids, saturated fatty acid, unsaturated fatty acid, monounsaturated, polyunsaturated, amphipathic. Concepts: the names and types of bonds between monomers of carbohydrates; classes of carbohydrates (include examples and functions), α and β glucose, 1-2 and 1-4 glycosidic linkages, alpha and beta glycosidic linkages, why are lipids not considered polymers? Phospholipid bilayer and modified carbohydrates. Make sure you can recognize the following structures: α and β glucose, triglyceride, phospholipid, cholesterol.

Carbohydrate

1. Organic molecules made of carbon, hydrogen, and oxygen, often used for energy storage and structural functions.

Monosaccharide

1. Simple sugars (e.g., glucose, fructose) that serve as monomers for carbohydrates.

Disaccharide

1. Two monosaccharides linked by a glycosidic bond (e.g., sucrose, lactose).

Oligosaccharide

1. Short chains of monosaccharides (3–20 units) often found in cell recognition and signaling.

Polysaccharide

1. Long chains of monosaccharides used for storage (starch, glycogen) or structure (cellulose, chitin).

Sugar

1. Simple carbohydrates, including monosaccharides and disaccharides.

Starch

A polysaccharide used by plants for energy storage.

Cellulose

A polysaccharide that provides structural support in plant cell walls.

Glycogen

A branched polysaccharide used for energy storage in animals.

Lipid

Hydrophobic molecules including fats, oils, phospholipids, and steroids.

Fatty acid

A hydrocarbon chain with a carboxyl group, used as a building block for lipids.

Triglyceride

A lipid composed of three fatty acids linked to a glycerol molecule.

Glycosidic linkage

1. A covalent bond between carbohydrate monomers.

Ester linkage -

The bond formed between a fatty acid and glycerol in lipids.

Steroids

1. Lipids with a four-ring structure (e.g., cholesterol, hormones).

Carotenoids

1. Pigments found in plants and some animals, important in photosynthesis.

Wax

Hydrophobic lipid molecules that provide protection and waterproofing.

Phospholipids

1. Lipids with a hydrophilic head and hydrophobic tails, key in forming cell membranes.

Acid

Fatty acid with no double bonds between carbons (solid at room temperature).

Unsaturated fatty acid

1. Fatty acid with one or more double bonds (liquid at room temperature).

Monounsaturated

Fatty acid with one double bond.

Polyunsaturated

Fatty acid with multiple double bonds.

Amphipathic

A molecule with both hydrophobic and hydrophilic properties (e.g., phospholipids).

Concepts

Types of bonds in carbohydrates

1. Glycosidic linkages between monosaccharides.

α and β glucose structures

1. Different orientations of hydroxyl groups in glucose.

1-2 vs. 1-4 glycosidic linkages

Different bonding patterns in carbohydrates

Why lipids are not polymers

Lipids are not made of repeating monomers

Phospholipid bilayer

Structure of cell membranes with hydrophobic tails and hydrophilic heads.

Recognizing structures

Be able to identify α and β glucose, triglycerides, phospholipids, and cholesterol.

Classes of carbohydrates & their functions

Monosaccharides (energy), Disaccharides (transport), Polysaccharides (storage, structure).