Download Organic Molecules

Organic Molecules
SC Biology Standard- B3.4- 3.5Summarize how
the structures of organic molecules are relative
to their caloric value and the function of
proteins, carbohydrates and fats in the human
body.
Organic Molecules:
All organisms are made of organic
molecules- which contain carbon
 Most organic molecules are made of
smaller units(monomers) bonded
together to form larger
molecules(polymers)
 ENERGY is stored in the bonds that link
these units together- varies with type of
molecule formed
 This energy = the caloric value
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Continued:
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Proteins, Carbohydrates and fats/lipids
are 3 organic molecules with different
structures and different caloric values
based upon those structures.
Proteins:
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Composed of chains of amino acid monomers
Amino acids are composed of carbon,
hydrogen, oxygen and nitrogen—sometimes
sulfur
20 different amino acids that chemically bond
to make different proteins.
12 of these are made in the body, the rest
must be consumed from foods such as nuts,
beans or meat.
Can be used for energy but only if no carbs or
lipids are available
Carbohydrates:
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Sugars and Starches
Composed of carbon, hydrogen and oxygen
Basic carbs are simple sugarsmonosaccharides such as glucose
Main source of energy for the cell
When carbs are consumed, process of
digestion breaks the bonds between larger
carbohydrate molecules so simple sugars can
be absorbed
Carbs continued:
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The bloodstream carries simple sugars
throughout the body where they cross into the
cell across the cell membrane
 Used as fuel for cellular respiration which
releases energy as ATP
 The caloric value of carbs is dependent upon
the number of carbon-hydrogen bonds.
 If an organism consumes more carbs than
needed for energy requirements, then it is
converted and stored as fat.
Monosaccharides
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Monosaccharides are the simplest
carbohydrate, made from only one sugar
molecule.
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Glucose (Blood sugar)
Galactose (Part of milk sugar)
 Fructose (Fruit sugar)
 Monosaccharides serve as a major fuel for
cells and as raw material for building
molecules
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Disaccharides/Polysaccharides
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Disaccharides are molecules made of two
monosaccharides bonded together.
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Sucrose: glucose + fructose = table sugar
Lactose: galactose + glucose = milk sugar
Maltose: glucose + glucose = alcohol sugar
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Polysaccharides are polymers (made of more
than two) of sugars.
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Polysaccharides have two main
purposes in living things:
Providing structure
 Energy storage
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Lipids/ Fats:
Composed of carbon, hydrogen and
small quantities of oxygen
 Made of two main molecules- glycerol
and fatty acids so structurally different
from carbohydrates
 Fats/lipids have more carbon-hydrogen
bonds than carbs
 Do not form polymers
 Source of energy when carbs are scarce,
but accumulates when plenty of carbs
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Fats/lipids continued:
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When fats are consumed- molecules are
broken down and absorbed into the
bloodstream
 Then blood carries fatty acids and glycerol
molecules throughout the body where they
enter into the cell through the cell membrane
 Stored in the cell for later use or as fuel for
cellular respiration if no carbs are available
 Cellular respiration releases energy held in the
chemical bonds of glycerol and fatty acids
More:
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Due to the structure and number of C-H
bonds, fats contain more energy (ATP)
per gram which explains why fats have a
higher caloric value
Functions:
Proteins are involved in almost every
function of the human body
 More important as Building blocks than
energy. Only energy if there is a
shortage of carbs or lipids
 Used as support for connective tissue
and keratin for hair and nails
 Transport proteins transport many
substances throughout the body
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Function of Proteins continued:
Hormone proteins coordinate activities
such as insulin
 Contractile proteins control movements
such as muscle movement
 Enzymes proteins accelerate the speed
of chemical reactions such as digestive
enzymes
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Function of Carbohydrates
Important source of energy
 Primary source of energy for cellular
respiration
 Some carbs are used for structural
material in plants= cellulose
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Function of lipids:
Used for energy when carbs are scarce
 Provide long term energy storage,
cushion vital organs and insulation for
the body
 Major component of cell membrane and
one of the raw materials necessary for
production of vitamins and hormones
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Identifying Organic compounds
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Must contain carbon
Most inorganic compounds do NOT have
carbon—Carbon dioxide (CO2) is NOT organic
even though it has carbon
Amino acids/ proteins contain an amino group
(-NH2) and an organic acid group (-COOH)
Lipids—the ratio of hydrogen to oxygen is
greater than 2:1.
Carbohydrates-the ratio of hydrogen to oxygen
is exactly 2:1.