Download Essential Nutrients

Chapter 8
Section 8.1
Essential Nutrients
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Chemicals of Life
• Living things are composed of nonliving chemicals.
• These chemicals are often grouped into
four major organic compounds:
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Carbohydrates
Lipids
Proteins
Nucleic Acids
1. Carbohydrates
• Carbohydrate – a molecule composed
of sugar subunits that contain carbon,
hydrogen and oxygen in a 1:2:1 ratio.
• Ex. Triose Sugars – C3H603
Hexose Sugars –C6H12O6
• The main function of a carbohydrate is
energy storage.
• Humans cannot make carbohydrates,
we must rely on consuming them from
plants.
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Carbohydrate Chemistry
• Carbohydrates are either single sugar units
or polymers of many sugar units.
• A polymer – is a molecule composed of
three or more subunits.
• When you think of polymers think of long
molecules formed by linking many small
similar chemical subunits.
• Carbohydrates can be classified according to
the number of sugar units they contain.
• Monosaccharide – a single sugar unit.
• Disaccharide – a sugar formed by joining two
monosaccharide subunits.
• Polysaccharide – a sugar composed of three or
more single sugar units.
Monosaccharides
Disaccharide
Polysaccharide
2. Lipids
• Lipids - fats and oils that are
insoluble in water (do not
dissolve).
• Their main functions are
energy storage and the
formation of cellular
membranes
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Lipid Chemistry
• Most lipids are composed of two
subunits: glycerol + fatty acids.
• There are two main groups of
lipids:
- Triglycerides
- Phospholipids
• Triglyceride – is a lipid composed
of glycerol and three fatty acids.
• There are two types of
triglycerides: saturated fatty acids
and unsaturated fatty acids.
Saturated Vs. Unsaturated
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Saturated Fatty Acids
Unsaturated Fatty
Acids
- no double covalent bonds
between carbon atoms, so
it contains all the possible
H atoms it can bond with
- has double bonds between
some carbon atoms,
leaving room for additional
H atoms
- cause the resulting fat to
be solid at room temp.
- cause resulting fat to be
liquid at room temp
- referred to as fat
- referred to as oils
Saturated Vs. Unsaturated
• Phospholipid – a lipid with a
phosphate molecule attached to the
glycerol.
• To form a phospholipid a negatively
charged phosphate replaces one of the
fatty acids attached to the glycerol in a
triglyceride.
Phospholipids are said to
be polar because they
have a negatively charged
head (phosphate) and a
positively charged tail (2
fatty acids).
3. Proteins
• Protein – a molecule made up of a chain
of amino acids.
• Amino acid – a chemical that contains
nitrogen; can be linked to form proteins.
• The main functions of proteins are
transport, blood clotting, support, immunity
and muscle action.
• Examples of Proteins
- Hemoglobin, collagen, antibodies and
enzymes.
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Protein Chemistry
• Proteins are made of several amino acids
linked together.
• Amino acids are linked together by a
peptide bond.
• Due to the peptide bonds a chain of three
or more amino acids can also be known
as a polypeptide.
Amino Acids
Peptide Bonds
Denaturation and Coagulation
• Denaturation – the process that occurs when the bonds
of a protein molecule are disrupted, causing a temporary
change in shape.
Ex  Oxygenated hemoglobin vs. deoxygenated
hemoglobin
• Coagulation – the process that occurs when the bonds
of a protein molecule are disrupted, causing a
permanent change in shape.
Ex  Boiling an egg.
• These processes can be caused by excess heat,
radiation or change in pH.
4. Nucleic Acids
• Nucleic Acids – polymers of
nucleotides.
• Their main function is the
transfer and expression of
genetic information.
• Examples of Nucleic Acids
are: DNA and RNA
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Chemistry of Nucleic Acids
• A nucleotide is a five carbon sugar
attached to 1 of the 4 nitrogen
containing bases:
- Adenine
- Guanine
- Cytosine
- Thymine
• Many nucleotides put together make up
the nucleic acid.
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Forming Organic Compounds
• 3 of the 4 organic compounds (carbs, lipids
and proteins) are formed in the same way.
• This process is known as dehydration
synthesis (dehydrolysis).
• Dehydration synthesis – the process by
which larger molecules are formed by the
removal of water from two smaller
molecules.
• In dehydration synthesis an OH group is
removed from one molecule and an H is
removed from the other compound.
• This forms a water molecule and connects
the two molecules by a covalent bond.
Breaking Organic Compounds
• These same 3 compounds are broken in
the same way.
• This process is the reverse of dehydration
synthesis and is known as hydrolysis.
• Hydrolysis – the process by which larger
molecules are split into smaller molecules
by the addition of water.
• In hydrolysis when water is added the
molecule breaks into its subunits.
• An OH group is added to one molecule
and a H is added to the other molecule.
Formation of a Disaccharide
or Polysaccharide
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Formation of a Lipid
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Formation of a Protein
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