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Bio-Chemistry
- 2. MacroMolecules
Macro = large
Molecules = 2 or more atoms
covalently bonded
Usually referred to as polymers
Like a chain
Made from several repeating subunits
The repeated subunits are called
monomers.
Like links in a chain
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- 3. Types of Macromolecules
There are four of them.
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids
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- 4. • Monomer – monosaccharide
• Chemical formula: (CH2O)n
• Carbon chains or rings with H’s, OH groups and a C=O
or carbonyl group. Depending on the placement of
the carbonyl group they may be aldoses or ketoses.
Carbohydrate Structure
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- 6. • Most monosaccharides have 3, 5, or 6 carbons.
– 3 carbons = triose
– 5 carbons = pentose
– 6 carbons = hexose
• Different placement of the OH groups creates several
different monosaccharides with the same chemical
formula.
Carbohydrate Structure
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- 8. • Polysaccharides consist of many monosaccharides
joined together by glycosidic bonds.
• One function of polysaccharides is energy storage
– it is hydrolyzed as needed.
• Other polysaccharides serve as building materials for
the cell or whole organism.
• Common polysaccharides:-
Starch
Glycogen
Cellulose
Chitin
Carbohydrate Structure
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- 9. • Starch is a storage polysaccharide composed entirely
of glucose monomers
– Great big chain of glucose molecules
Carbohydrate Structure
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- 10. Biological Uses of Polysaccharides
• Plants store starch within plastids, including
chloroplasts.
• Plants can store surplus glucose in starch and
withdraw it when needed for energy or carbon.
• Animals that feed on plants, especially parts rich in
starch, can also access this starch to support their
own metabolism.
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- 12. Functions of Carbohydrates
• Energy production (glucose and fructose) and
storage (glycogen and starch).
• Cell identity markers – carbohydrate chains attached
to cell membrane proteins identify the type of cell.
• Building blocks for other molecules such as, DNA
and RNA, amino acids and lipids.
• Structural - cellulose, chitin, peptidoglycans.
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- 13. Lipids
• Lipids are an exception among macromolecules
because they do not have polymers.
– Though lipid structure is easily recognized
• Lipids all have little or no affinity for water.
• Lipids are highly diverse in form and function.
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- 14. Lipids - Diverse
Hydrophobic Molecules
1. Fats store large amounts of energy.
2. Phospholipids are major components of cell
membranes.
3. Steroids include cholesterol and certain hormones.
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- 15. 1. Fats store large amounts of energy
• Although fats are not strictly polymers, they are large
molecules assembled from smaller molecules by
dehydration reactions.
• A fat is constructed from two kinds of smaller
molecules, glycerol and fatty acids.
Structures and functions lipids
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- 16. • Glycerol consists of a three carbon skeleton with a
hydroxyl group attached to each.
• A fatty acid consists of a carboxyl group attached to
a long carbon skeleton, often 16 to 18 carbons long.
Structures and functions lipids
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- 17. • The many nonpolar C-H bonds in the long
hydrocarbon skeleton make fats hydrophobic.
• In a fat, three fatty acids are joined to glycerol by an
ester linkage, creating a triacylglycerol.
Structures and functions lipids
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- 18. • The three fatty acids in a fat can be the same or different.
• Fatty acids may vary in length (number of carbons) and in
the number and locations of double bonds.
• If there are no carbon-
carbon double bonds,
then the molecule is a
saturated fatty acid - a
hydrogen at every
possible position.
Structures and functions lipids
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- 19. • If there are one or more carbon-carbon double
bonds, then the molecule is an unsaturated fatty
acid - formed by the removal of hydrogen atoms
from the carbon skeleton.
• Saturated fatty acids are
straight chains, but
unsaturated fatty acids
have a kink wherever
there is a double bond
Structures and functions lipids
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- 20. Saturated vs. Unsaturated
• Fats with saturated fatty acids are saturated fats.
– Most animal fats
– solid at room temperature.
– A diet rich in saturated fats may contribute to cardiovascular
disease (atherosclerosis) through plaque deposits.
• Fats with unsaturated fatty acids are unsaturated
fats.
– Plant and fish fats, known as oils
– Liquid are room temperature.
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- 21. 2. Phospholipids are major components of cell
membranes
• Phospholipids have two fatty acids attached
to glycerol and a phosphate group at the third
position.
• The “head” likes water
• The “tail” hates water
Structures and functions lipids
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- 22. • The interaction of phospholipids with water is complex.
– The fatty acid tails are hydrophobic, but the phosphate group
and its attachments form a hydrophilic head.
Structures and functions lipids
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- 23. • At the surface of a cell phospholipids are arranged as
a bilayer.
– the hydrophilic heads are on the outside in contact with the aqueous
solution and the hydrophobic tails form the core.
– The phospholipid bilayer forms a barrier between the cell and the
external environment.
• They are the major component of cell membranes.
Structures and functions lipids
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- 24. 3. Steroids include cholesterol and certain hormones.
• Steroids are lipids with a carbon skeleton
consisting of four fused carbon rings.
– Different steroids are created by varying functional groups
attached to the rings.
Structures and functions lipids
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- 25. • Proteins are instrumental in about everything that an
organism does.
– structural support,
– storage
– transport of other substances
– intercellular signaling
– movement
– defense against foreign substances
– Proteins are the main enzymes in a cell and regulate
metabolism by selectively accelerating chemical reactions.
• Humans have tens of thousands of different proteins,
each with their own structure and function.
Proteins
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- 26. Proteins
1. A polypeptide is a polymer of amino acids
connected to a specific sequence .
2. A protein’s function depends on its specific
conformation.
Many Structures, Many Functions
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- 27. • Proteins are the most structurally complex molecules
known.
– Each type of protein has a complex three-
dimensional shape or conformation.
• All protein polymers are constructed from the same
set of 20 monomers, called amino acids.
• Polymers of proteins are called polypeptides.
• A protein consists of one or more polypeptides
folded and coiled into a specific conformation
Proteins
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- 28. A polypeptide is a polymer of amino acids
connected in a specific sequence
• Amino acids consist of four components attached
to a central carbon, the alpha carbon.
• These components include a hydrogen atom, a
carboxyl group, an amino group, and a side chain.
• Polypeptides are made of amino acids
– Amino acids CONTAIN NITROGEN (N)
Proteins
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- 30. • The repeated sequence (N-C-C) is the polypeptide
backbone.
• Attached to the backbone are the various R groups.
• Polypeptides range in size from a few monomers to
thousands.
Proteins
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- 32. Nucleic Acids
• Contain genetic information
– Provides instructions for making polypeptides
• Each monomer is a nucleotide
• Nucleotides are composed of
1. 5 carbon sugar
Deoxyribose
ribose
2. Phosphate group
3. Nitrogenous base
Adenine (A)
Thymine (T) in DNA, Uracil (U) in RNA
Guanine (G)
cytosine
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- 33. • Deoxyribonucleic acid (DNA)
– Sugar is deoxyribose
– Shape is a double helix
• Ribonucleic acid (RNA)
– Sugar is ribose
– Uses a different nitrogenous base
– Uracil (U) instead of thymine (T)
– Shape may be a single or double helix
Nucleic Acids
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- 34. THE END
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