Download Document

TORTORA • FUNKE
• CASE
Microbiology
AN INTRODUCTION
EIGHTH EDITION
B.E Pruitt & Jane J. Stein
Chapter 2, part B
Chemical Principles
PowerPoint® Lecture Slide Presentation prepared by Christine L. Case
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Important Biological Molecules
• Organic compounds always contain carbon
and hydrogen.
• Inorganic compounds typically lack carbon.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Inorganic Compounds: Water
• Polar molecule
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.4a
Inorganic Compounds: Water
• Solvent
• Polar
substances
dissociate,
forming
solutes
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.5
Inorganic Compounds: Water
• H+ and OH participate in chemical reactions
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Inorganic Compounds: Water
• Hydrogen bonding
between water
molecules makes
water a temperature
buffer.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.4b
Acids, Bases, and Salts
• An acid is a
substance that
dissociates into one
or more H+.
HCl  H+ + Cl
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.6a
Acids, Bases, and Salts
• A base is a
substance that
dissociates into one
or more OH.
NaOH  Na+ + OH
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.6b
Acids, Bases, and Salts
• A salt is a substance
that dissociates into
cations and anions,
neither of which is H+
or OH.
NaCl  Na+ + Cl
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.6c
Acid-Base Balance
• 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.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Acid-Base Balance
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.7
Organic Compounds
• 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.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Table 2.3.1
Organic Compounds
• Small organic molecules can combine into large
macromolecules.
• Macromolecules are polymers consisting of many
small repeating molecules.
• The smaller molecules are called monomers.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Organic Compounds
• Monomers join by dehydration synthesis or
condensation reactions.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.8
Carbohydrates
• Are important for structure and as energy sources.
• Consist of C, H, and O with the formula (CH2O)n
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.8
Carbohydrates
• Monosaccharides are simple sugars with 3 to 7
carbon atoms.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.8
Carbohydrates
• Disaccharides are formed when two monosaccharides
are joined in a dehydration synthesis.
• Disaccharides can be broken down by hydrolysis.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.8
Carbohydrates
• 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.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Lipids
• Are the primary components of cell membranes.
• Consist of C, H, and O.
• Are nonpolar and insoluble in water.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Simple 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.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.9c
Complex lipids
• Contain C, H, and
O + P, N, or S.
• Membranes are
made of
phospholipids
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.10a
Steroids
• Consist of four
carbon rings, with
an –OH group
attached to one
ring.
• Are part of
membranes.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.11
Proteins
• Are essential in cell structure and function.
• Enzymes are proteins that speed chemical reactions.
• Transporter proteins move chemicals across
membranes.
• Flagella are made of proteins.
• Some bacterial toxins are proteins.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Proteins
• Consist of subunits called amino acids.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Table 2.4.1
Proteins
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Table 2.4.2
Amino Acids
• Exist in either of
two
stereoisomers, D
or L.
• L-forms are most
often found in
nature.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.13
Peptide Bonds
• Peptide bonds between amino acids are formed by
dehydration synthesis.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.14
Levels of Protein Structure
• The primary structure is a polypeptide chain
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.15a
Levels of Protein Structure
• The secondary structure occurs when the amino acid
chain folds and coils in a regular helix or pleats.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.15b
Levels of Protein Structure
• The tertiary structure occurs when the helix folds
irregularly, forming disulfide bonds, hydrogen bonds,
and ionic bonds between amino acids in the chain.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.15c
Levels of Protein Structure
• The quaternary structure consists of two or more
polypeptides.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.15d
Level of Protein Structure
• Conjugated proteins consist of amino acids and other
organic molecules:
• Glycoproteins
• Nucleoproteins
• Lipoproteins
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Nucleic Acids
• Consist of nucleotides.
• Nucleotides consist of a:
• Pentose
• Phosphate group
• Nitrogen-containing (purine or pyrimidine) base
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.16
DNA
• Has deoxyribose
• Exists as a
double helix
• A hydrogen
bonds
with T
• C hydrogen
bonds
with G
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.16
RNA
• Has ribose
• Is single-stranded
• A hydrogen bonds
with U
• C hydrogen bonds
with G
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.17
ATP
• Has ribose, adenine, and 3 phosphate groups
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.18
ATP
• Is made by dehydration synthesis.
• Is broken by hydrolysis to liberate useful energy for the
cell.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings