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STRUCTURE AND FUNCTION OF
LARGE BIOLOGICAL MOLECULES

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On molecular scale
carbohydrates, proteins, nucleic acids are huge and therefore called
macromolecules
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Large biomolecules are
constantly broken down and synthesized by the cell
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Hydrolysis breaks down large molecules
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These processes are made easier by enzymes
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Carbohydrates

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Carbohydrates include sugars and polymers of sugars
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Monosaccharides generally have a molecular formula of
(CH2O)n
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Depending on the location of the carbonyl
group, the sugar can be either an aldose or a ketose
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ketone has a carbonyl group within
the carbon skeleton
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Some of these
disaccharides are maltose,sucrose and lactose
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Sucrose or table sugar is formed by glucose and
fructose
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Polysaccharides are macromolecules, made of few hundred or few thousand
monosaccharides
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Some are storage units,others
are building materials for structures that protect the cell
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These are the store units in animals and
plants
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Chitin is used by the arthropods to build their exoskeletons
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Lipids are grouped together because they share 1 important trait
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Lipids are a class of biomolecules that aren’t true polymers and aren’t
big enough to be called macromolecules
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Biologically important lipids are fats, phospholipids and steroids
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Glycerol
is an alcohol, in which each of its three carbons bear a hydroxyl group
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When making fat,3 fatty acid molecules are joined to one glycerol by an
aster linkage
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Saturated fats
have no double bonds
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Phospholipids are similar to fat molecules but have 2 fatty acids joined to glycerol
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Proteins

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Thus, giving phospholipids hydrophobic and
hydrophilic ends
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They surround the cell as a phospholipid bilayer , protecting the cell from external
environment and controlling the flow of substances in and out of the cell
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Amino acids all have an amino group
and a carboxyl group
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Some proteins regulate and control the speed
of all chemical reactions in the cells
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The resulting bond is called peptide linkage and the chain of amino acids a
polypeptide
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Defensive blood cells move through the blood as antibodies,
protecting the organisms
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Receptor

proteins receive and transmit signals into cells
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Sometimes though proteins may unravel, losing its
specific shape and function in a process called denaturation
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There are 2 types of nucleic acids:DNA and RNA
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RNA(ribonucleic acid) delivers information from DNA to ribosomes and
helps secrete proteins
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Each nucleotide
consists of 3 parts
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Sugar in the DNA is
deoxyribose, in RNA it is ribose
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Each DNA nucleotide has one of four nitrogenous bases:
adenine(A), thymine(T), cytosine(C) and guanine(G)
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To build a polypeptide, sugar of one nucleotide bonds
to a phosphate group of the next nucleotide, making a
sugar-phosphate backbone
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DNA molecule contains
2 polynucleotide strands, which wind around each other
forming a double helix
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Nucleotide

Pairs: adenine-thymine, cytosine-guanine in RNA adenine-uracil

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The 2 DNA strands are held together by hydrogen bonds
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