Introduction to 9 th Grade Biology Biomolecules

Classes of Biomolecules Carbohydrates Lipids Proteins Nucleic Acids

Carbohydrates Monosaccharaides (simple) Glucose- Found in Honey Fructose – Fruit! Galactose – Found in Milk Disaccharides (complex) Sucrose – Table Sugar Lactose – Milk Sugar Maltose – Found in Seeds, grains

Lipids Our body needs them for insulation, cushioning, and energy storage. Three important groups – Fats & Oils – Phospholipids (cell membrane) – Steroids (cholesterol)

Structure of Fatty Acids Long chains of mostly carbon and hydrogen atoms with a -COOH group at one end. When they are part of lipids, the fatty acids resemble long flexible tails.

Saturated and Unsaturated Fats Unsaturated fats : – liquid at room temp – one or more double bonds between carbons in the fatty acids allows for “kinks” in the tails – most plant fats Saturated fats: – have only single C-C bonds in fatty acid tails – solid at room temp – most animal fats

Phospholipids Structure: Glycerol + 2 fatty acids + phosphate group. Function: Main structural component of membranes, where they arrange in bilayers.

Phospholipids in Water

Steroids Structure: Four carbon rings with no fatty acid tails Functions: Component of animal cell membranes Modified to form sex hormones

Steroid ring structure The common structural feature of steroids is that their molecules contain the following ring skeleton.

Proteins Combination of 20 amino acids Functions – Structure – Transport – Hormones – Cell identification & communication – Metabolism

Amino Acid Structure

Amino Group- NH2 Carboxyl Group- COOH R Group/Side Chain- blank space that determines the type of amino acid

Nucleic Acid Three important Nucleic Acids – DNA- Genetic Code, working instructions for the cell. Stores genetic information. (double stranded with a Double Helix shape like a 3-D twisted ladder) [Deoxyribonucleic Acid] – RNA- transfers the genetic information (single stranded) [Ribonucleic Acid] – ATP- Provides energy for all cells

Nucleotide – monomer that makes up nucleotides. Consists of a pentose molecule, a phosphate molecule and a nitrogen base ribose molecule – a 5-carbon sugar (pentose) phosphate group – an ion of 1 phosphorus and 4 oxygen nitrogenous base – nitrogen containing ring structures. Purines – adenine (A) and guanine (G) Pyrimidines – cytosine (C), thymine (T) and uracil (U) – (note: A and T form pairs while G and C form pairs in DNA but in RNA T is replaced with Uracil and so U pairs with T)

Nucleotide Structure

Pyrimidines are single ring nitrogen bases Notice that Thymine, Cytosine and Uracil are your pyrimidine nitrogen bases.

Purines are double ring nitrogen bases Notice that Adenine and Guanine are your purines nitrogen bases.