chapter 2 the chemistry of microbiology. i. elements: substances that can not be broken down into...
TRANSCRIPT
![Page 1: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/1.jpg)
Chapter 2The Chemistry of
Microbiology
![Page 2: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/2.jpg)
I. Elements: Substances that can not be broken down
into simpler substances by chemical reactions.
There are 92 naturally occurring elements: Oxygen, carbon, nitrogen, calcium, sodium, etc.
Life requires about 25 of the 92 elementsChemical Symbols:
Abbreviations for the name of each element.
Usually one or two letters of the English or Latin name of the element
First letter upper case, second letter lower case. Example: Helium (He), sodium (Na), potassium (K), gold (Au).
![Page 3: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/3.jpg)
Main Elements: Over 98% of an organism’s mass is made up of six elements.
Oxygen (O): 65% body mass Cellular respiration, component of water, and
most organic compounds.Carbon (C): 18% of body mass.
Backbone of all organic compounds.Hydrogen (H): 10% of body mass.
Component of water and most organic compounds.
Nitrogen (N): 3% of body mass. Component of proteins and nucleic acids
(DNA/RNA)Calcium (Ca): 1.5% of body mass.
Bones, teeth, clotting, muscle and nerve function.
Phosphorus (P): 1% of body mass Bones, nucleic acids, energy transfer (ATP),
phospholipids.
![Page 4: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/4.jpg)
Minor Elements: Found in low amounts. Between 1% and 0.01%.
Potassium (K): Main positive ion inside cells. Nerve and muscle function.
Sulfur (S): Component of most proteins.Sodium (Na): Main positive ion outside
cells. Fluid balance, nerve function.
Chlorine (Cl): Main negative ion outside cells. Fluid balance.
Magnesium (Mg): Component of many enzymes and chlorophyll.
![Page 5: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/5.jpg)
Trace elements: Less than 0.01% of mass: Boron (B)Chromium (Cr)Cobalt (Co)Copper (Cu)Iron (Fe)Fluorine (F)Iodine (I)Manganese (Mn)Molybdenum (Mo)Selenium (Se)Silicon (Si)Tin (Sn)Vanadium (V)Zinc (Zn)
![Page 6: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/6.jpg)
II. Structure & Properties of AtomsAtoms: Smallest particle of an element that retains its chemical properties. Made up of three main subatomic particles.
Particle Location Mass ChargeProton (p+) In nucleus 1 +1Neutron (no) In nucleus 1
0Electron (e-) Outside nucleus 0* -1
* Mass is negligible for our purposes.
![Page 7: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/7.jpg)
![Page 8: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/8.jpg)
Structure and Properties of Atoms
1. Atomic number = # protons The number of protons is unique for each
elementEach element has a fixed number of protons
in its nucleus. This number will never change for a given element.
Written as a subscript to left of element symbol.Examples: 6C, 8O, 16S, 20Ca
Because atoms are electrically neutral (no charge), the number of electrons and protons are always the same.
In the periodic table elements are organized by increasing atomic number.
![Page 9: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/9.jpg)
Structure and Properties of Atoms:2. Mass number = # protons + # neutrons
Gives the mass of a specific atom.Written as a superscript to the left of the
element symbol.Examples: 12C, 16O, 32S, 40Ca.
The number of protons for an element is always the same, but the number of neutrons may vary.
The number of neutrons can be determined by:
# neutrons = Mass number - Atomic number
![Page 10: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/10.jpg)
Structure and Properties of Atoms:
3. Isotopes: Variant forms of the same element.
Isotopes have different numbers of neutrons and therefore different masses.
Isotopes have the same numbers of protons and electrons.
Example: In nature there are three forms or isotopes of carbon (6C): 12C: About 99% of atoms. Have 6 p+, 6 no, and 6
e-. 13C: About 1% of atoms. Have 6 p+, 7 no, and 6 e-. 14C: Found in tiny quantities. Have 6 p+, 8 no, and
6 e-. Radioactive form (unstable). Used for dating fossils.
![Page 11: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/11.jpg)
Electrons Determine How Atoms Bond with Other Atoms
A. Energy levels: Electrons occupy different energy levels around the nucleus. Level (Shell) Electron Capacity1 2 (Closest to nucleus, lowest
energy)
2 83 8 (If valence shell, 18
otherwise)
4, 5, & 6 18
B. Electron configuration: Arrangement of electrons in orbitals around nucleus of atom.
C. Valence Electrons: Number of electrons in outer energy shell of an atom.
![Page 12: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/12.jpg)
![Page 13: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/13.jpg)
III. How Atoms Form Molecules: Chemical Bonds
Molecule: Two or more atoms combined chemically.
Compound: A substance with two or more elements combined in a fixed ratio. Water (H2O) Hydrogen peroxide (H2O2) Carbon dioxide (CO2) Carbon monoxide (CO) Table salt (NaCl)
Atoms are linked by chemical bonds.Chemical Formula: Describes the chemical
composition of a molecule of a compound. Symbols indicate the type of atomsSubscripts indicate the number of atoms
![Page 14: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/14.jpg)
How Atoms Form Molecules: Chemical Bonds
“Octet Rule”: When the outer shell of an atom is not full, i.e.: contains fewer than 8 (or 2) electrons (valence e-), the atom tends to gain, lose, or share electrons to achieve a complete outer shell (8, 2, or 0) electrons.
Example: Sodium has 11 electrons, 1 valence electron.Sodium loses its electron, becoming an ion:Na -------> Na+ + 1 e-
1(2), 2(8), 3(1) 1(2), 2(8)Outer shell has 1 e- Outer shell is fullSodium atom Sodium ion
![Page 15: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/15.jpg)
Number of Valence Electrons Determine the Chemical Behavior of Atoms
Element Valence CombiningTendency
Electrons CapacitySodium 1 1 Lose 1Calcium 2 2 Lose 2Aluminum 3 3 Lose 3Carbon 4 4 Share 4Nitrogen 5 3 Gain 3Oxygen 6 2 Gain 2Chlorine 7 1 Gain 1Neon* 8 0 Stable
* Noble gas
![Page 16: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/16.jpg)
1 Valence electron 4 Valence electrons 5 Valence electrons 6 Valence electrons
![Page 17: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/17.jpg)
How Atoms Form Molecules: Chemical Bonds
Atoms can lose, gain, or share electrons to satisfy octet rule (fill outermost shell).
Two main types of Chemical Bonds
A. Ionic bond: Atoms gain or lose electrons
B. Covalent bond: Atoms share electrons
![Page 18: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/18.jpg)
A. Ionic Bond: Atoms gain or lose electrons. Bonds are attractions between ions of opposite charge.
Ionic compound: One consisting of ionic bonds.
Na + Cl ----------> Na+ Cl-
sodium chlorine Table salt(Sodium
chloride)Two Types of Ions:Anions: Negatively charged particle (Cl-)
Cations: Positively charged particle (Na+)
![Page 19: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/19.jpg)
![Page 20: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/20.jpg)
B. Covalent Bond - Involve the “sharing” of one or more pairs of electrons between atoms.Covalent compound: One consisting of covalent bonds.Example: Methane (CH4): Main component of natural gas.
H |
H---C---H |H
Each line represents on shared pair of electrons.
Octet rule is satisfied: Carbon has 8 electrons,
Hydrogen has 2 electrons
![Page 21: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/21.jpg)
![Page 22: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/22.jpg)
There May Be More Than One Covalent Bond Between Atoms:
1. Single bond: One electron pair is shared between two atoms.Example: Chlorine (Cl2), water (H2O); methane (CH4)
Cl Cl
2. Double bond: Two electron pairs share between atoms.Example: Oxygen gas (O2); carbon dioxide (CO2)
O=O3. Triple bond: Three electron pairs shared between two atoms.Example: Nitrogen gas (N2)
N = N
![Page 23: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/23.jpg)
Number of Covalent Bonds:
Carbon (4) Nitrogen (3)Oxygen (2)Sulfur (2)Hydrogen (1)
![Page 24: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/24.jpg)
Two Types of Covalent Bonds: Polar and Nonpolar
A. Electronegativity: A measure of an atom’s ability to attract and hold onto a shared pair of electrons.Some atoms such as oxygen or nitrogen have a much higher electronegativity than others, such as carbon and hydrogen.Element ElectronegativityO 3.5N 3.0
S & C 2.5P & H 2.1
![Page 25: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/25.jpg)
Polar and Nonpolar Covalent Bonds
B. Nonpolar Covalent Bond: When the atoms in a bond have equal or similar attraction for the electrons (electronegativity), they are shared equally.
Example: O2, H2, N2, Cl2
C. Polar Covalent Bond: When the atoms in a bond have different electronegativities, the electrons are shared unequally. Electrons are closer to the more electronegative atom creating a polarity or partial charge.Example: H2O
Oxygen has a partial negative charge. Hydrogens have partial positive
charges.
![Page 26: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/26.jpg)
![Page 27: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/27.jpg)
Other Bonds: Weak chemical bonds are important in the chemistry of living things.
Hydrogen bonds: Attraction between the partially positive H of one molecule and a partially negative atom of another
Hydrogen bonds are about 20 X easier to break than a normal covalent bond.
Responsible for many properties of water.Determine 3 dimensional shape of DNA and
proteins.Chemical signaling (molecule to receptor).
![Page 28: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/28.jpg)
![Page 29: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/29.jpg)
Water - A Unique Compound for Life
![Page 30: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/30.jpg)
Water: The Ideal Compound for Life
Living cells are 70-90% water
Water covers 3/4 of earth’s
surface
Water is the ideal solvent for
chemical reactions
On earth, water exists as gas,
liquid, and solid
![Page 31: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/31.jpg)
I. Polarity of water causes hydrogen bonding
Water molecules are held together by H-bonding
Partially positive H attracted to partially
negative O atom.
Individual H bonds are weak, but the
cumulative effect of many H bonds is very
strong.
![Page 32: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/32.jpg)
Unique properties of water caused by H-bonds
Cohesion: Water molecules stick to each other.
Adhesion: Water molecules stick to many
surfaces.
Stable Temperature: Water resists changes in
temperature.
High heat of vaporization: Water must absorb
large amounts of energy (heat) to evaporate.
Expands when it freezes (water denser than ice)
Solvent: Dissolves many substances.
![Page 33: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/33.jpg)
![Page 34: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/34.jpg)
II. Biological Consequences of Water’s PolarityA. Capillary Action: Water tends to rise in narrow
tubes. This is caused by two factors: Cohesion: Molecules of water “stick together” Adhesion: Water molecules stick to walls of tubes.
Examples: Upward movement of water through plant
vessels and fluid in blood vessels.
B. Surface tension: Difficulty in “stretching or breaking”
At water/air interface, difficult to pull water apart
Causes water to “bead” into tiny balls
Used by some insects who live on the surface of water
![Page 35: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/35.jpg)
C. Temperature RegulationWater has a very high specific heat
Specific Heat: Amount of heat energy needed to raise 1 g of substance 1 degree Celsius
Specific Heat of Water: 1 calorie/gram/degree C Organisms can absorb a lot of heat without drastic
changes in temperature.
D. Evaporative Cooling Vaporization: Transformation from liquid to gas. Heat of Vaporization: Energy required to convert 1
gram of a liquid -> gas is high (540 calories/gram) Sweating is a form of evaporative cooling. Can regulate temperature w/o great water loss.
![Page 36: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/36.jpg)
E. Ice floats on Water: Life Can Exist in Bodies of WaterIce floats because liquid water is more dense
than ice (solid water).
Water gets more dense as it cools to 4oC.
Water gets less dense (expands) as it cools
further to form ice.
Crystalline lattice forms, molecules farther
apart
Because ice floats, life can survive and thrive in bodies of water, even though the earth has gone through many winters and ice ages
![Page 37: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/37.jpg)
III. Water is the ideal solvent for chemical reactionsSolution: Homogeneous mixture of 2 or more
substances. Examples: Salt water, air, tap water.
Solvent: Dissolving substance of a solution. Example: Water, alcohol, oil.
Solute: Substance dissolved in the solvent. Example: NaCl, sugar, carbon dioxide.
Aqueous solution: Water is the solvent.Solubility: Ability of substance to dissolve in a
given solvent.
![Page 38: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/38.jpg)
Solubility of a Solute Depends on its Chemical Nature
Two Types of Solutes:A. Hydrophilic: “Water loving” dissolve
easily in water. Ionic compounds (e.g. salts) Polar compounds (molecules with polar
regions) Examples: Compounds with -OH groups
(alcohols). “Like dissolves in like”
B. Hydrophobic: “Water fearing” do not dissolve in water Non-polar compounds (lack polar regions) Examples: Hydrocarbons with only C-H non-
polar bonds, oils, gasoline, waxes, fats, etc.
![Page 39: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/39.jpg)
![Page 40: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/40.jpg)
ACIDS, BASES, pH AND BUFFERS
A. Acid: A substance that donates protons (H+). Separate into one or more protons and an
anion:
HCl (into H2O ) -------> H+ + Cl-
H2SO4 (into H2O ) --------> H+ + HSO4-
Acids INCREASE the relative [H+] of a solution.
Water can also dissociate into ions, at low levels:
H2O <======> H+ + OH-
![Page 41: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/41.jpg)
B. Base: A substance that accepts protons (H+). Many bases separate into one or more positive
ions (cations) and a hydroxyl group (OH- ). Bases DECREASE the relative [H+] of a
solution ( and increases the relative [OH-] )
H2O <======> H+ + OH-
Directly NH3 + H+ <=------> NH4+
Indirectly NaOH ---------> Na+ + OH-
( H+ + OH- <=====> H2O )
![Page 42: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/42.jpg)
Strong acids and bases: Dissociation is almost complete (99% or more of molecules).
HCl (aq) -------------> H+ + Cl-
NaOH (aq) -----------> Na+ + OH-
(L.T. 1% in this form) (G.T. 99% in dissociated form) A relatively small amount of a strong acid or base will
drastically affect the pH of solution.
Weak acids and bases: A small percentage of molecules dissociate at a give time (1% or less)
H2CO3 <=====> H+ + HCO3-
carbonic acid Bicarbonate ion
(G.T. 99% in this form) (L.T. 1% in dissociated form)
![Page 43: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/43.jpg)
C. pH scale: [H+] and [OH-]pH scale is used to measure how basic or
acidic a solution is.Range of pH scale: 0 through 14.
Neutral solution: pH is 7. [H+ ] = [OH-]
Acidic solution: pH is less than 7. [H+ ] > [OH-]
Basic solution: pH is greater than 7. [H+ ] < [OH-]
As [H+] increases pH decreases (inversely
proportional).
Logarithmic scale: Each unit on the pH scale
represents a ten-fold change in [H+].
![Page 44: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/44.jpg)
pH of Common Solutions
![Page 45: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/45.jpg)
D. Buffers keep pH of solutions relatively constant
Buffer: Substance which prevents sudden large changes in pH when acids or bases are added.
Buffers are biologically important because most of the chemical reactions required for life can only take place within narrow pH ranges.
Example: Normal blood pH 7.35-7.45. Serious health
problems will arise if blood pH is not stable.
![Page 46: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/46.jpg)
CHEMICAL REACTIONS
A chemical change in which substances (reactants) are joined, broken down, or rearranged to form new substances (products).
Involve the making and/or breaking of chemical bonds.
Chemical equations are used to represent chemical reactions.Example:
2H2 + O2 -----------> 2H2O
2 Hydrogen Oxygen 2 WaterMolecules Molecule Molecules
![Page 47: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/47.jpg)
Organic Compounds
![Page 48: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/48.jpg)
I. Organic Chemistry: Carbon Based Compounds
Organic Compounds: Compounds that contain carbon and are synthesized by cells (except CO and CO2).Diverse group: Several million organic
compounds are known. More are identified daily.Common: After water, organic compounds are
the most common substances in cells. Over 98% of the dry weight of living cells is made up of
organic compounds. Less than 2% of the dry weight of living cells is made
up of inorganic compounds.
Inorganic Compounds: Compounds without carbon.
![Page 49: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/49.jpg)
Carbon Has 4 Valence Electrons and Can Form 4 Covalent Bonds
![Page 50: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/50.jpg)
Organic Compounds are Incredibly Diverse
Organic molecules can vary dramatically in: Length (1-100s of C atoms) Shape (Linear chain, branched, ring) Type of bonds:
Single Double Triple bonds
Other elements that bond to C: Nitrogen (N) Oxygen (O) Hydrogen (H) Sulfur (S) Phosphorus (P)
![Page 51: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/51.jpg)
Carbon Skeletons of Organic Compounds
![Page 52: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/52.jpg)
Diversity of Organic CompoundsHydrocarbons:
Organic molecules that contain C and H only. Good fuels, but not biologically important.Undergo combustion (burn in presence of
oxygen).In general they are chemically stable.Nonpolar: Do not dissolve in water
(Hydrophobic).
Examples: (1C) Methane: CH4 (2C) Ethane: CH3CH3 (3C) Propane: CH3CH2CH3 (4C) Butane: CH3CH2CH2CH3 (5C) Pentane: CH3CH2CH2CH2CH3 (6C) Hexane: CH3CH2CH2CH2CH2CH3 (7C) Heptane: CH3CH2CH2CH2CH2CH2CH3 (8C) Octane: CH3CH2CH2CH2CH2CH2CH2CH3
![Page 53: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/53.jpg)
Hydrocarbons have C and H only
![Page 54: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/54.jpg)
Isomers: Compounds with same chemical formula but different structures
Structural Isomers: Differ in atom arrangement:
Example: Isomers of C4H10
Butane (C4H10) Isobutane (C4H10)
CH3--CH2--CH2--CH3 CH3--CH--CH3 |CH3
Isomers have different physical and chemical properties.
![Page 55: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/55.jpg)
II. Functional Groups Determine Chemical & Physical Properties of Organic MoleculesCompounds that are made up solely of carbon and
hydrogen (hydrocarbons) are not very reactive.In an organic compound, the groups of atoms that
usually participate in chemical reactions are called functional groups. Groups of atoms that have unique chemical and physical
properties. Biologically important functional groups:
Hydroxyl (-OH) Carbonyl (=C=O) Carboxyl (-COOH) Amino (-NH2)
Notice that all are polar.
![Page 56: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/56.jpg)
A. Hydroxyl Group (-OH)Polar group: Polar covalent bond between O
and H.
Can form hydrogen bonds with other polar
groups.
Generally makes molecule water soluble.
Found in:
Alcohols: Organic molecules with a simple
hydroxyl group. Examples: Methanol (wood alcohol, toxic) Ethanol (drinking alcohol) Propanol (rubbing alcohol)
Sugars
Water soluble vitamins
![Page 57: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/57.jpg)
B. Carbonyl Group (=CO)Polar group
O can be involved in H-bonding.
Generally makes molecule water soluble.
Found in:
Aldehydes: Carbonyl is located at end of
molecule
Ketone: Carbonyl is located in middle of
molecule
Examples: Sugars (Aldehydes or ketones)
Formaldehyde (Aldehyde)
Acetone (Ketone)
![Page 58: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/58.jpg)
Sugars Have Both -OH and =CO Functional Groups
![Page 59: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/59.jpg)
C. Carboxyl Group (-COOH)Polar group
Generally makes molecule water soluble
Acidic because it can donate H+ in solution
Found in:
Carboxylic acids: Organic acids, can increase acidity of a solution. Examples: Acetic acid: Sour taste of vinegar. Ascorbic acid (Vitamin C): Found in fruits
and vegetables. Amino acids: Building blocks of proteins.
![Page 60: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/60.jpg)
D. Amino Group (-NH2)Polar group
Generally makes molecule water soluble
Weak base because N can accept a H+
Amine: General term given to compound
with (-NH2)
Found in:
Amino acids: Building blocks of
proteins.
Urea in urine. From protein breakdown.
![Page 61: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/61.jpg)
Amino acid Structure:
Central carbon with:H atomCarboxyl groupAmino groupVariable R-group
Amino Acid Structure: H |
(Amino Group) NH2---C---COOH (Carboxyl group)
| R(Varies for each amino acid)
![Page 62: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/62.jpg)
Amino Acids Have -NH2 and -COOH Groups
![Page 63: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/63.jpg)
The Macromolecules of Life:
Carbohydrates, Proteins, Lipids, and Nucleic Acids
![Page 64: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/64.jpg)
Most Biological Macromolecules are PolymersPolymer: Large molecule consisting of many
identical or similar “subunits” linked through covalent bonds.
Monomer: “Subunit” or building block of a polymer.
Macromolecule: Large organic polymer. Most macromolecules are constructed from about 70 simple monomers.
Only about 70 monomers are used by all living things on earth to construct a huge variety of molecules
Structural variation of macromolecules is the basis for the enormous diversity of life on earth.
![Page 65: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/65.jpg)
Relatively few monomers are used by cells to make a huge variety of macromolecules
Macromolecule Monomers or Subunits
1. Carbohydrates 20-30 monosaccharidesor simple sugars
2. Proteins 20 amino acids
3. Nucleic acids (DNA/RNA) 4 nucleotides
(A,G,C,T/U)
4. Lipids (fats and oils) ~ 20 different fatty
acids
and glycerol.
![Page 66: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/66.jpg)
Making PolymersA. Condensation or Dehydration Synthesis
reactions: Process in which one monomer is covalently
linked to another monomer (or polymer). The equivalent of a water molecule is removed.Anabolic Reactions: Make large molecules from
smaller ones. Require energy (endergonic)General Reaction:
Enzyme
X - OH + HO - Y --------> X - O - Y + H2OMonomer 1 Monomer 2 Dimer
Water(Unlinked) (or Polymer) (or Polymer)
Example: Enzyme
Glucose + Fructose ---------> Sucrose + H2O
![Page 67: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/67.jpg)
![Page 68: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/68.jpg)
Breaking PolymersB. Hydrolysis Reactions: “Break with water”.Break down polymers into monomers.Bonds between subunits are broken by
adding water.Catabolic Reactions: Break large molecules
into smaller ones. Release energy (exergonic)
General Reaction: Enzyme
X - O - Y + H2O ----------> X - OH + HO - YPolymer Water Monomer 1 Monomer 2
(or Dimer)
Example: Enzyme
Sucrose + H2O ---------> Glucose + Fructose
![Page 69: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/69.jpg)
![Page 70: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/70.jpg)
Synthesis and Hydrolysis of Sucrose
![Page 71: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/71.jpg)
I. Carbohydrates: Molecules that store energy and are used as building materials
General Formula: (CH2O)n
Simple sugars and their polymers.Diverse group includes sugars, starches,
cellulose.Biological Functions:
Fuels, energy storage Structural component (cell walls) DNA/RNA component
Three types of carbohydrates:A. MonosaccharidesB. Disaccharides C. Polysaccharides
![Page 72: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/72.jpg)
A. Monosaccharides: “Mono” single & “sacchar” sugar
Preferred source of chemical energy for cellsCan be synthesized by plants from light, H2O and
CO2.
Store energy in chemical bonds.Carbon skeletons used to synthesize other
molecules.
Characteristics:1. Have 3-8 carbons. -OH on each carbon; one with
C=O2. Names end in -ose. Based on number of carbons:
5 carbon sugar: pentose 6 carbon sugar: hexose
3. Can exist in linear or ring forms4. Isomers: Many molecules with the same
molecular formula, but different atomic arrangement Example: Glucose and fructose are both C6H12O6
Fructose is sweeter than glucose
![Page 73: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/73.jpg)
Monosaccharides Can Have 3 to 8 Carbons
![Page 74: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/74.jpg)
Linear and Ring Forms of Glucose
![Page 75: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/75.jpg)
B. B. DisaccharidesDisaccharides: : ““DiDi”” double & double & ““saccharsacchar”” sugar sugar
Covalent bond formed by condensation reaction Covalent bond formed by condensation reaction between 2 monosaccharides.between 2 monosaccharides.
ExamplesExamples::
1. 1. MaltoseMaltose: Glucose + Glucose. : Glucose + Glucose.
• Energy storage in seeds. Energy storage in seeds.
• Used to make beer.Used to make beer.
2. 2. LactoseLactose: Glucose + Galactose. : Glucose + Galactose.
• Found in milk.Found in milk.
• Lactose intoleranceLactose intolerance is common among adults. is common among adults.• May cause gas, cramping, bloating, diarrhea, etc.May cause gas, cramping, bloating, diarrhea, etc.
3. 3. SucroseSucrose: Glucose + Fructose. : Glucose + Fructose.
• Most common disaccharide (table sugar). Most common disaccharide (table sugar).
• Found in plant sap.Found in plant sap.
![Page 76: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/76.jpg)
Maltose and Sucrose are Disaccharides
![Page 77: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/77.jpg)
C. Polysaccharides: “Poly” many (8 to
1000)
Functions: Storage of chemical energy and
structure.
Storage polysaccharides: Cells can store simple sugars in polysacharides and hydrolyze them when needed.
1. Starch: Glucose polymer (Helical) Form of glucose storage in plants (amylose) Stored in plant cell organelles called
plastids
2. Glycogen: Glucose polymer (Branched) Form of glucose storage in animals (muscle
and liver cells)
![Page 78: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/78.jpg)
Structural Polysaccharides: Used as structural components of cells and tissues.
1. Cellulose: Glucose polymer. The major component of plant cell walls. CANNOT be digested by animal enzymes. Only microbes have enzymes to hydrolyze
cellulose, found in digestive systems of: Cows, goats, and rabbits Termites
2. Chitin: Polymer of an amino sugar (with NH2 group)
Forms exoskeleton of arthropods (insects) Found in cell walls of some fungi
![Page 79: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/79.jpg)
![Page 80: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/80.jpg)
![Page 81: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/81.jpg)
II. Proteins: Large three-dimensional macromolecules responsible for most cellular functions
Polypeptide chains: Polymers of amino acids linked by peptide bonds in a specific linear sequence.
Protein: Macromolecule composed of one or more polypeptide chains folded into a specific three-dimensional conformation.
![Page 82: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/82.jpg)
Proteins Have Important and Varied Functions:Proteins Have Important and Varied Functions:
1.1. EnzymesEnzymes: : Catalysis of cellular reactionsCatalysis of cellular reactions
2. 2. Structural ProteinsStructural Proteins: : Maintain cell shapeMaintain cell shape
3. 3. TransportTransport: : Transport in cells/bodies (e.g. hemoglobin). Transport in cells/bodies (e.g. hemoglobin).
Channels and carriers across cell membrane.Channels and carriers across cell membrane.
4. 4. CommunicationCommunication: : Chemical messengers, hormones, and Chemical messengers, hormones, and
receptors.receptors.
5. 5. DefensiveDefensive: : Antibodies and other molecules that bind to Antibodies and other molecules that bind to
foreign molecules and help destroy them.foreign molecules and help destroy them.
6. 6. ContractileContractile: : Muscular movement.Muscular movement.
7. 7. StorageStorage: : Store amino acids for later use (e.g. egg white).Store amino acids for later use (e.g. egg white).
Protein functionProtein function is is dependentdependent upon its upon its 3-D shape3-D shape..
![Page 83: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/83.jpg)
Polypeptide: Polymer of amino acids connected in a specific sequence
A. Amino acid: The monomer of polypeptides
Central carbon with:H atomCarboxyl groupAmino groupVariable R-group
Amino Acid Structure: H |
(Amino Group) NH2---C---COOH (Carboxyl group)
| R(Varies for each amino acid)
![Page 84: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/84.jpg)
A Protein’s Specific Shape (Conformation) Determines its Function
Conformation: The 3-D structure of a protein.
Determined by the amino acid sequence.
Four Levels of Protein Structure
1. Primary structure: Linear amino acid
sequence, determined by gene for that
protein.
2. Secondary structure: Regular
coiling/folding of polypeptide. Alpha helix or beta sheet. Caused by H-bonds between amino acids.
![Page 85: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/85.jpg)
3. Tertiary structure: Overall 3-dimensional
shape of a polypeptide chain.
4. Quaternary structure: Only found in
proteins with 2 or more polypeptides.
Overall 3-D shape of all polypeptide chains.
Example: Hemoglobin (2 alpha and 2 beta
polypeptides)
![Page 86: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/86.jpg)
![Page 87: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/87.jpg)
![Page 88: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/88.jpg)
![Page 89: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/89.jpg)
What determines a protein’s Conformation ?
A. Primary structure: Exact location of each amino acid along the chain determines folding pattern
Example: Sickle Cell Hemoglobin protein
Mutation changes amino acid #6 on the alpha chain.
Defective hemoglobin causes red blood cells to assume sickle shape, which damages tissue and capillaries.
Sickle cell anemia gene is carried in 10% of African Americans.
![Page 90: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/90.jpg)
B. Chemical & Physical Environment: Presence of other compounds, pH, temperature, salts.
Denaturation: Process which alters native conformation and therefore biological activity of a protein
pH and salts: Disrupt hydrogen, ionic bonds.Temperature: Can disrupt weak
interactions.Example: Function of an enzyme depends on
pH, temperature, and salt concentration.
![Page 91: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/91.jpg)
III. Nucleic Acids: Store and Transmit Hereditary Information for All Living Things
There are two types of nucleic acids in cells:
A. Deoxyribonucleic Acid (DNA)
Has segments called genes which provide information to make each and every protein in a cell
Double-stranded molecule which replicates each time a cell divides.
B. Ribonucleic Acid (RNA)
Three main types called mRNA, tRNA, rRNA RNA molecules are copied from DNA and used to make gene
products (proteins). Usually exists in single-stranded form.
![Page 92: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/92.jpg)
DNA and RNA are Polymers of NucleotidesNucleotide: Subunits of DNA or RNA.
Nucleotides have three components:
1. Pentose sugar (ribose or deoxyribose)2. Phosphate group to link nucleotides (-PO4)
3. Nitrogenous base (A,G,C,T or U) Purines: Have 2 rings.
Adenine (A) Guanine (G)
Pyrimidines: Have one ring. Cytosine (C) Thymine (T) in DNA or uracil (U) in RNA.
![Page 93: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/93.jpg)
![Page 94: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/94.jpg)
James Watson and Francis Crick determined the 3-D shape of DNA in 1953
Double helix: The DNA molecule is a double helix.Antiparallel: The two DNA strands run in opposite
directions. Strand 1: 5’ to 3’ direction (------------>) Strand 2: 3’ to 5’ direction (<------------)
Complementary Base Pairing: A & T (U) and G & C. A on one strand hydrogen bonds to T (or U in RNA). G on one strand hydrogen bonds to C.
Replication: The double-stranded DNA molecule can easily replicate based on A=T and G=C pairing.
---
SEQUENCE of nucleotides in a DNA molecule dictate the amino acid SEQUENCE of polypeptides
![Page 95: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/95.jpg)
DNA is a Double Helix Held Together by H-Bonds
![Page 96: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/96.jpg)
A Gene is a specific segment of a DNA molecule with information for cell to make one polypeptide
DNA (transcribed into single stranded RNA “copy”)
! ! mRNA (single stranded “copy” of the gene) ! !Polypeptide (mRNA message translated
into polypeptide)
![Page 97: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/97.jpg)
![Page 98: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/98.jpg)
IV. Lipids: Fats, phospholipids, and steroids
Diverse groups of compounds.Composition of Lipids: C, H, and small amounts of O.
Functions of Lipids:Biological fuelsEnergy storageInsulationStructural components of cell membranesHormones
![Page 99: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/99.jpg)
Lipids: Fats, phospholipids, and steroids
1. Simple Lipids: Contain C, H, and O only.
A. Fats (Triglycerides). Glycerol : Three carbon molecule with three hydroxyls. Fatty Acids: Carboxyl group and long hydrocarbon
chains.Characteristics of fats:
Most abundant lipids in living organisms. Hydrophobic (insoluble in water) because nonpolar. Economical form of energy storage (provide 2X the
energy/weight than carbohydrates). Greasy or oily appearance.
![Page 100: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/100.jpg)
Lipids: Fats, phospholipids, and steroids
Simple Lipids: Continued
Saturated fats: Hydrocarbons saturated with H. Lack -C=C- double bonds.Solid at room temp (butter, animal fat, lard)
Unsaturated fats: Contain -C=C- double bonds.Usually liquid at room temp (corn, peanut, olive
oils)Trans fats: Fats that are artificially created by
chemically saturating unsaturated fats. Margarine (partially hydrogenated oils)
![Page 101: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/101.jpg)
![Page 102: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/102.jpg)
![Page 103: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/103.jpg)
2. Complex Lipids: In addition to C, H, and O, also contain other elements, such as phosphorus, nitrogen, and sulfur.A. Phospholipids: Are composed of:
Glycerol 2 fatty acids, Phosphate group
Amphipathic Molecule Hydrophobic fatty acid “tails”. Hydrophilic phosphate “head”.
Function: Primary component of the plasma membrane of cells
![Page 104: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/104.jpg)
![Page 105: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/105.jpg)
![Page 106: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/106.jpg)
B. Steroids: Lipids with four fused carbon ringsIncludes cholesterol, bile salts, reproductive, and
adrenal hormones. Cholesterol: The basic steroid found in animals
Common component of animal cell membranes. Precursor to make sex hormones (estrogen, testosterone) Generally only soluble in other fats (not in water) Too much increases chance of atherosclerosis.
C. Waxes: One fatty acid linked to an alcohol. Very hydrophobic. Found in cell walls of certain bacteria, plant and insect
coats. Help prevent water loss.
![Page 107: Chapter 2 The Chemistry of Microbiology. I. Elements: Substances that can not be broken down into simpler substances by chemical reactions. There are](https://reader035.vdocuments.us/reader035/viewer/2022062408/56649ed95503460f94be80d4/html5/thumbnails/107.jpg)