Transcript The Chemistry of Life

The Chemistry of Life
The Properties of Water
The Water Molecule
The water molecule (H20) is neutral.
 Polar molecules- a molecule in which the
charges are unevenly distributed. They also
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can attract to each other.
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Ex. Water is a polar molecule because the oxygen
end is slightly negative and the hydrogen end is
slightly positive.
The Water Molecule
Hydrogen Bond- the attraction between
the hydrogen atom on one water
molecule and the oxygen atom on
another water molecule.
 They are not as strong as covalent or
ionic bonds.
 These bonds give water its special
properties.
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The Water Molecule
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Cohesion – an attraction between molecules
of the same substance.
Example : Water forms beads on smooth surfaces;
insects can walk on a pond’s surface.
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Adhesion – an attraction between molecules
of different substances.
Example : reading the volume in a graduated
cylinder at eye level shows the
water dipping in the center.
Solutions and Suspensions
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Mixture – a material composed of two or
more elements or compounds that are
physically mixed together but not
chemically combined.
Example: Stirring together salt/pepper,
sugar/sand.
Solutions
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It is a mixture in which all the components are
evenly distributed throughout the mixture.
 Table salt in warm water – the sodium and
the chloride ions are attracted to the polar
water molecules thus the salt dissolves into
the water.
 Solute – substance that is dissolved. Ex. salt
 Solvent – substance in which the solute
dissolves. Ex. water
Suspensions
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Mixture of water and nondissolved
material.
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Ex. Blood that circulates through your body; Italian
dressing
Acids, Bases, and pH
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pH scale – measurement system that
indicates the concentration of hydrogen
(H+) ions in a solution.
• Scale from 0 to 14.
• Pure water has a pH of 7.
• Water molecules can form a hydrogen ion (H+)
or a hydroxide ion (OH-)
Acids, Bases, and pH
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Acids – any compound that forms H+
ions in a solution.
• The lower end (below 7) of a pH scale.
• Has a higher concentration of H+ ions than OHor pure water.
• The lower the pH the greater the acidity.
• Ex.-Stomach acid, lemon juice, tomato juice,
acid rain.
Acids, Bases, and pH
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Bases – a compound that produces OHions in a solution. Alkaline
• The higher end (above 7) of a pH scale.
• Has a lower concentration of H+ ions than OHor pure water.
• The higher the pH the stronger the base.
• Ex.-oven cleaner, bleach, ammonia solutions,
soap.
Carbon Compounds
The Chemistry of Carbon
Organic Chemistry
The study of all compounds that contain
bonds between carbon atoms.
 Carbon compounds are also called
organic compounds.
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Polymerization
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Process in which macromolecules are
formed. Macromolecules are very large
molecules.
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Monomers are small units that join
together to make macromolecules, or
polymers.
4 groups of organic compounds
found in living things:
Carbohydrates
 Lipids
 Nucleic acids
 Proteins
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Carbohydrates
Made up of carbon, hydrogen, and
oxygen atoms.
 Living things use it as their main source
of energy.
 Living things store sugar as complex
carbohydrates known as starches.
 Ex. pasta
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Carbohydrates
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Monosaccharides - a single sugar molecule. Ex.Galactose which is a component of milk; Fructose
which is found in many fruits.
Polysaccharides - a large macromolecule formed
from monosaccharides. Many animals store excess
sugar in a polysaccharide called glycogen, or animal
starch.
Carbohydrates

When glucose is low, liver releases glycogen.
 Muscles store glycogen for muscle contraction.
 Plants use a polysaccharide known as plant starch to
store sugar.
 Cellulose is a polysaccharide made by plants which
is tough and flexible and gives plants their strength.
Ex. Wood and paper
Lipids
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Made mostly from carbon and hydrogen atoms.
Fats, oils and waxes.
Used in living things to store energy.
Some are important parts of biological membranes
and waterproof coverings.
Made up on compounds called fatty acids and
glycerol.
Steroids are lipids
Lipids
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Saturated - the fatty acid contains the maximum possible
number of hydrogen atoms.
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Unsaturated – the fatty acid has at least one carbon-carbon
double bond. Ex. Olive oil.
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Polyunsaturated – the fatty acid contains more than one double
bond. Ex. Corn oil, canola oil.
Nucleic Acids
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Contain hydrogen, oxygen, nitrogen, carbon, and
phosphorus.
Nucleotides – are monomers that makeup nucleic
acids.
Each nucleotide consists of a 5-carbon sugar, a
phosphate group, and a nitrogenous base.
They store and transmit hereditary, or genetic,
information.
2 Kinds of Nucleic Acids
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Ribonucleic acid (RNA)
• Contains the sugar ribose
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Deoxyribonucleic acid (DNA)
• Contains the sugar deoxyribose
Proteins
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Contain nitrogen as well as carbon, hydrogen, and
oxygen.
 Are polymers of molecules called amino acids.
 Are one of the most diverse macromolecules.
 Some proteins control the rate of reactions and
regulate cell processes.
 Some are used to form bones and muscles.
 Others transport substances into or out of cells or
help fight disease.
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Alanine
Serine
Chemical Reactions & Enzymes
Chemical Reaction – a process that changes
one set of chemicals (reactants) into another
set of chemicals (products).
 Chemical Reactions - always involve the
breaking of bonds in reactants and the
formation of new bonds in products.
 Some chemical reactions release energy
(often spontaneously), and others absorb
energy.
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Chemical Reactions & Enzymes
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Activation energy – the starting energy a chemical
reaction needs to get started.
Catalyst – a substance that speeds up the rate of a
chemical reaction.
Enzymes – are proteins that act as biological
catalysts. They speed up chemical reactions by
lowering the activation energy.
Regulation of Enzyme Activity
Enzymes that help digest food work
best at certain pH values.
 Many are affected by changes in
temperatures. Temps close to 37
degrees C (normal body temp.)
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