Microbiology AN INTRODUCTION EIGHTH EDITION TORTORA FUNKE CASE Chapter 2, part B Chemical Principles

Important Biological Molecules Organic compounds always contain carbon and hydrogen. Inorganic compounds typically lack carbon.

Polar molecule Inorganic Compounds: Water Figure 2.4a

Solvent –Polar substances dissociate, forming solutes Inorganic Compounds: Water Figure 2.5

H + and OH  participate in chemical reactions Inorganic Compounds: Water

Hydrogen bonding between water molecules makes water a temperature buffer. Inorganic Compounds: Water Figure 2.4b

An acid is a substance that dissociates into one or more H +. HCl  H + + Cl  Acids, Bases, and Salts Figure 2.6a

A base is a substance that dissociates into one or more OH . NaOH  Na + + OH  Acids, Bases, and Salts Figure 2.6b

A salt is a substance that dissociates into cations and anions, neither of which is H + or OH . NaCl  Na + + Cl  Acids, Bases, and Salts Figure 2.6c

The amount of H + in a solution is expressed as pH. pH =  log[H + ] Increasing [H + ], increases acidity. Increasing [OH  ] increases alkalinity. Most organisms grow best between pH 6.5 and 8.5. Acid-Base Balance

Figure 2.7

The chain of carbon atoms in an organic molecule is the carbon skeleton. Functional groups are responsible for most of the chemical properties of a particular organic compound. Organic Compounds

Table 2.3.1

Small organic molecules can combine into large macromolecules. Macromolecules are polymers consisting of many small repeating molecules. The smaller molecules are called monomers. Organic Compounds

Monomers join by dehydration synthesis or condensation reactions. Organic Compounds Figure 2.8

Are important for structure and as energy sources. Also for structures like cell walls Consist of C, H, and O with the formula (CH 2 O) n Carbohydrates Figure 2.8

Monosaccharides are simple sugars with 3 to 7 carbon atoms. Carbohydrates Figure 2.8

Disaccharides are formed when two monosaccharides are joined in a dehydration synthesis. Disaccharides can be broken down by hydrolysis. Carbohydrates Figure 2.8

Oligosaccharides consist of 2 to 20 monosaccharides. Polysaccharides consist of tens or hundreds of monosaccharides joined through dehydration synthesis. Starch, glycogen, dextran, and cellulose are polymers of glucose that are covalently bonded differently. Chitin is a polymer of two sugars repeating many times. What is Chitin? Carbohydrates

Three types of lipids: –Simple fats also known as triglycerides –Phospholipids –Steroids Are the primary components of cell membranes. Function as storage of energy, membrane structure and some act as hormones (steroids). Consist of C, H, and O. Are nonpolar and insoluble in water. Lipids

Called fats or triglycerides contain glycerol and fatty acids; formed by dehydration synthesis. Unsaturated fats have one or more double bonds in the fatty acids. Simple lipids Figure 2.9c

Contain C, H, and O + P, N, or S. Membranes are made of phospholipids Phospholipids lipids Figure 2.10a

Consist of four carbon rings, with an –OH group attached to one ring. Are part of membranes. Steroids Figure 2.11

Are essential in cell structure and function as enzymes. Enzymes are proteins that speed chemical reactions. Transporter proteins move chemicals across membranes. Flagella are made of proteins. Some bacterial toxins are proteins. Proteins

Consist of monomer subunits called amino acids. Proteins Table 2.4.1

Proteins Table 2.4.2

Exist in either of two stereoisomer s, D or L. L -forms are most often found in nature. Amino Acids Figure 2.13

Peptide bonds between amino acids are formed by dehydration synthesis. Peptide Bonds Figure 2.14

The primary structure is a polypeptide chain Levels of Protein Structure Figure 2.15a

The secondary structure occurs when the amino acid chain folds and coils in a regular helix or pleats. Levels of Protein Structure Figure 2.15b

The tertiary structure occurs when the helix folds irregularly, forming disulfide bonds, hydrogen bonds, and ionic bonds between amino acids in the chain. Levels of Protein Structure Figure 2.15c

The quaternary structure consists of two or more polypeptides. Levels of Protein Structure Figure 2.15d

Conjugated proteins consist of amino acids and other organic molecules: Glycoproteins Nucleoproteins Lipoproteins Level of Protein Structure

Consist of monomer units called nucleotides. Nucleotides consist of a: Pentose Phosphate group Nitrogen-containing (purine or pyrimidine) base Adenine, thymine, guanine or cytosine Nucleic Acids Figure 2.16

Has the sugar deoxyribose Exists as a double helix with sugar and phosphate as backbone A hydrogen bonds with T C hydrogen bonds with G DNA Figure 2.16

Has sugar ribose Is single-stranded A hydrogen bonds with U C hydrogen bonds with G RNA Figure 2.17

Has ribose, adenine, and 3 phosphate groups ATP Figure 2.18

Is made by dehydration synthesis. Is broken by hydrolysis to liberate useful energy for the cell. ATP