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 OHto 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 Acids
are 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.