biology 107 macromolecules i september 5, 2003

Biology 107Biology 107

Macromolecules IMacromolecules I

September 5, 2003September 5, 2003

Macromolecules IMacromolecules IStudent Objectives:Student Objectives: As a result of this lecture and the assigned reading, you As a result of this lecture and the assigned reading, you

should understand the following:should understand the following:

1.1. The four major types of organic macromolecules are: The four major types of organic macromolecules are: carbohydrates, lipids, carbohydrates, lipids, proteins, and nucleic acidsproteins, and nucleic acids..

2.2. Carbohydrates generally have molecular formulas that are some multiple of Carbohydrates generally have molecular formulas that are some multiple of CHCH22O, and carbohydrates range from single small sugar molecules O, and carbohydrates range from single small sugar molecules (monosaccharides) to long polymers of sugar monomers (polysaccharides). (monosaccharides) to long polymers of sugar monomers (polysaccharides).

a.a. Structure - Structure - Monosaccharides have two or more -OH groups Monosaccharides have two or more -OH groups and and either an aldehyde or a ketone group.either an aldehyde or a ketone group. Polysaccharides Polysaccharides may be straight or may be straight or branched molecules of hundreds or branched molecules of hundreds or thousands of sugar thousands of sugar monomers. Some sugars are highly monomers. Some sugars are highly negatively charged because negatively charged because they are commonly sulfated they are commonly sulfated (SO(SO3-3-) or because they contain a carboxyl ) or because they contain a carboxyl group (COOgroup (COO--).).

Macromolecules IMacromolecules Ib.b. Functions - energy source, recognition or signaling, Functions - energy source, recognition or signaling, and/or and/or structural.structural.

3.3. Lipids consist mainly of C and H atoms linked by nonpolar Lipids consist mainly of C and H atoms linked by nonpolar covalent bonds; consequently, lipids are not attracted to polar covalent bonds; consequently, lipids are not attracted to polar water molecules, and lipids are hydrophobic.water molecules, and lipids are hydrophobic.

a.a. Structure – Structure – Fats and oilsFats and oils are large lipids made from glycerol and fatty acids. are large lipids made from glycerol and fatty acids. Triglyceride fats consist of three (3) fatty acid chains hooked to a Triglyceride fats consist of three (3) fatty acid chains hooked to a glycerol molecule. For glycerol molecule. For saturated fatssaturated fats, every C atom of the carbon , every C atom of the carbon skeleton (except the carboxyl carbon) carries 2 H atoms (the skeleton (except the carboxyl carbon) carries 2 H atoms (the maximum number of hydrogens). In contrast, maximum number of hydrogens). In contrast, unsaturated fatsunsaturated fats contain double bonds and less than the maximum number of contain double bonds and less than the maximum number of hydrogens possible.hydrogens possible.

Macromolecules IMacromolecules I

Phospholipids, the major components of cellular membranes, are structurally similar to fats except they contain a phosphate group and only 2 fatty acid chains attached to the glycerol.

Steroids are lipids with the carbon chain bent to form fused rings. Cholesterol is a common substance in animal cell membranes. Animal cells also use cholesterol as a precursor for making other steroids, including male and

female sex hormones.

b. Functions - energy storage, membrane structure, hormone signaling, and/or insulation.

Four Main Types of MacromoleculesFour Main Types of Macromolecules

Common Carbohydrates Classified by Number of Common Carbohydrates Classified by Number of CarbonsCarbons

Examples of Hexose Isomers

Examples of Linear Compared to Ring Forms of Examples of Linear Compared to Ring Forms of CarbohydrateCarbohydrate

Disaccharides

PolysaccharidesPolysaccharides

Examples:Examples:

StarchStarch

CelluloseCellulose

Lipids - Fats

Triglyceride Fats

Saturated Fatty Acid ChainsSaturated Fatty Acid Chains

Unsaturated Fatty Acid Chains Unsaturated Fatty Acid Chains

PhospholipidsPhospholipids

Phospholipids in Water

Structure of Phospholipids and Steroids

Examples of Lipids Other Than Phospholipids or Steroids