Chapter 2

Chemical Principles for the Microbiologist.

Why is this (Chemistry) important:

• Life is made up of simple to complex chemical reactions.

• Nutrients that life use are made of chemical components.

• Chemical properties determine how life acts– Life is made from a few simple components

put together according to a few simple rules

The world is made up of

• Matter

• Energy

Atoms

• Define• What are they?

Elements

• Define

• What are they?

• What are the most common ones?

• Where can they be found in the environment?

• Are all forms usable?

2.1

Molecules: Two or more atoms

• How are molecules held together?– Ionic bonds– Covalent bonds– Hydrogen bonds

Covalent bonds

Ionic bonds

Hydrogen bonds

Solubility in water???

• Solvent

• Solute

• hydrophobic

• hydrophilic

Concentrations in solution

• Grams/liter = milligrams/milliliter

• Moles/liter=millimoles/milliliter

• What is a mole?

• C6H12O6

Important molecules and their properties

The properties of living things depend on the properties of the chemicals that make them up.

The presence of two ions is very important to chemical reactions

• Proton, hydrogen ion

• Hydroxide ion

• How does the above relate to the below?

• Oxidation loss of electrons

• Reduction gain of electrons

Acids and bases

• Acids create H+ and an anion

• Bases create OH- and a cation

• Acids have a pH below 7ph

• Bases have a pH above 7ph

• Buffers stabilize pH by giving of H+ or OH- to maintain a constant pH.

Organic compounds:

• Made by life

• Always contain carbon and hydrogen

• Used to make the structures of life

• Used to store energy in the form of chemical bonds

Know the following

• Carbohydrates

• Lipids

• Proteins

• Nucleic acids

Carbohydrates

• Carbon, hydrogen and oxygen

• Sugars and starches

• -saccharides

• Isomers-same chemical formula different structural properties– Glucose and fructose

• Dehydration synthesis makes polymers

• Hydrolysis breaks apart polymers

Synthesis or lysis

Lipids

• Insolubility in water

• Fats are triglycerides

• Saturated lipid has no double bonds

• Phospholipids make up membranes

• Steroids: signals and alter physical properties of the membranes

Functional groups of AA

10 of the 20 different amino acids

Proteins

• Aa are building blocks

• Carbon, hydrogen, oxygen nitrogen and sulfur

• Aa linked by peptide bonds

• 4 levels of structure

Nucleic acids

• DNA and RNA

• Pentose, phosphate and nitrogen base

• Information molecule of the cell.

Chemical reactions and enzymes

• What type of molecules are enzymes?

• What are some of their properties?

• From Chapter 5 microbial metabolism

Typical chemical reactions

• Making or braking of chemical bonds between atoms

• Result in an overall change of energy• Are almost always reversible• To take place reactants must collide with each

other• Activation energy is the minimal amount of

energy that system must have• Enzymes accelerate chemical reactions by

lowering activation energy.

• Enzyme reactions are reversible.

Essential Amino Acidsare required in the diet because?

Beans and Legumes

•Isoleucine

•Lysine

In both

•Valine

•Histidine

•Threonine

•Phenylalanine

•Leucine

Corn and Grains

•Tryptophan

•Methionine

Types of Chemical Reactions

• Synthesis or Anabolism

• Decomposition reactions or catabolism

• Exchange reactions

• Almost all reactions are reversible

• Remind nick to put this up on the board.