Transcript Ch 2 - Fort Bend ISD

The Chemistry of Microbiology
Chapter 2
Atoms
• Matter is anything that takes up space and
has mass
• The smallest and basic chemical unit is an
atom
• Consist of negatively charged electron which
orbit around the uncharged neutrons and
positive charged protons
• Elements is matter composed of a single type
of atom
Atoms
• The atomic number depends on the number
of protons in the nucleus in the atom
• The atomic mass is the sum of all the protons,
neutrons, and electron. We mainly add the
protons and neutrons and not the electrons
because the electron have little mass.
• Isotopes are atoms of an element that differ
only in the numbers of neutrons they contain
Chemical Bonds
• Electron shells are the region of space occupied
by electrons
• The atom’s reactivity depends on the number of
electrons on the outermost shell, or valence
electrons.
• Chemical bond is when electrons are transferred
or shared to complete the valence shell.
• The first shell only holds two electrons and the
rest shells hold a maximum of eight electrons
Chemical Bonds
• Electronegativity is the strength of the atom’s attraction for
electrons
• The electronegativity determines whether the bond is
going to be a nonpolar covalent bond, a polar covalent
bond, or an ionic bond
• Nonpolar covalent bond is equal sharing of the electrons.
• Polar covalent bond is unequal sharing of the electrons
• Ionic bond is a bond in which one or more electrons from
one atom are removed and attached to another atom
• Positive charged ions are called cations and negatively
charged ions are called anions
Chemical Bonds
• Molecule consist of two or more atoms held
together by a chemical bond
• A molecule that contains atoms of more than one
element is a compound
• Organic compounds that contain carbon and
hydrogen atoms are called organic compounds
• Hydrogen bond is the electrical attractions
between a partially charged hydrogen atom and a
full or partial negative charge on either a
different region of the same molecule or another
molecule.
Chemical Reaction
• A process where reactants are changed into
products by making or breaking chemical bond
results in a chemical reaction
• Synthesis reactions form larger, more complex
molecules
• In dehydration synthesis a molecule of water is
removed from the reactants as the larger
molecule is formed
• Endothermic reaction requires energy
• Anabolism is the sum of all synthesis reaction in
an organism
Chemical Reaction
• Decomposition reactions break larger molecules into
smaller molecule
• Exothermic reaction releases energy
• Hydrolysis is a decomposition reaction that uses water
as one of the reactants
• Catabolism is the sum of decomposition reaction in an
organism
• Exchange reactions involve exchanging atoms between
reactants
• The sum of all anabolic, catabolic, and exchange
chemical reactions in an organism is metabolism
Water, Acids, Bases, and Salts
• Inorganic molecules lack carbon
• Water is a vital inorganic compound because of its
properties as a solvent
• Acids release hydrogen ions
• Bases release hydroxyl anions
• The pH scale measures the hydrogen ion
concentration in a substance
• Buffers are substances that prevent drastic changes in
pH
• Salt is a compound that dissociates in water into
cations and anions.
Organic Macromolecules
• Functional groups are found in organic
macromolecules
• Monomers are simple subunits that can be
covalently linked to form polymers
• Lipids (include fat, phospholipids, waxes, and
steroids) are hydrophobic (repel water)
macromolecules
Organic Macromolecules
• Fat molecules are formed from a glycerol and
three chainlike fatty acid
• Saturated fatty acid which contains more
hydrogen in their structural formulas than
unsaturated fatty acid
• Unsaturated fatty acid contains double bond
between some carbon acid
• Polyunsaturated fat are double bonds that
exist in the fatty acids of a molecule of fat
Organic Macromolecules
• Phospholipids contain two fatty acid chains and a
phosphate functional group. The phospholipid head is
hydrophilic, where the fatty acid is hydrophobic
• Waxes contain a long chain fatty acid covalently linked
to a long chain alcohol. It is also components of cell
wall and used as energy storage molecules
• Steroid lipids (Cholesterol) help maintain the structure
of the membrane as the temperature increases
• Carbohydrates (monosaccharaides, disaccharides, and
polysaccharides) serve as energy sources and
structural molecule
Organic Macromolecules
• Protein are structural components of cells,
enzymatic catalyst, regulators of various
activities, molecules involved in the
transportation of substances, and defensive
molecules
• Denaturation of a protein disrupts its structure
and its function
• Also, they are composed of amino acids linked by
peptide bonds, and they possess primary,
secondary, and tertiary structure
Organic Macromolecules
• Deoxyribonucleic acid (DNA) and Ribonucleic
acid (RNA) are unbranched macromolecular
polymers of nucleotides, each composed either
of deoxyribose or ribose sugar, ionized
phosphate, and a nitrogenous base.
• Five nitrogenous bases: Adenine, Guanine,
Cytosine, Thymine, and Uracil.
• DNA consist of A, G, C, and T
• RNA consist of A, G, C, and U
• Nucleic acids structure allows genetic diversity
Organic Macromolecules
• Adenosine triphosphate (ATP) is the most
important short-term energy storage molecule
in the cell.