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Organic molecules and macromolecules
Organic molecules are based around the carbon atom
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Carbohydrates
Carbohydrates are a group of molecules that includes sugars and starches/ They
represent 1-2% of cell mass
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All human cells have glucose as an energy source
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They play a role in the osmotic balance of the body
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Sugar is a major component of the nucleic acids, DNA and RNA
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Diabetes
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Picking up sugar in the blood
o All cells in the body start to lose water
o Crenation – cells lose water and become shriveled
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The larger the carbohydrate, the less soluble it is in water
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Contain three to seven carbon atoms
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In this synthesis reaction, a water molecule is lost as the bond
is made
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This decomposition process is called hydrolysis and is essentially the
reverse dehydration synthesis
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Sucrose
o Glucose + fructose
Lactose
o Glucose + galactose
o Digested by the enzyme lactase
o 97% is kept in the gut
o If there are low levels – lactose intolerant

Polysaccharides are long chains of simple sugars linked together by dehydration
synthesis
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Only two polysaccharides are of major importance to the body:
starch and glycogen
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o The number of glucose units composing a starch molecule is high and
variable
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- Glycogen
o The storage carbohydrate of animal tissues
o It is stored primarily in skeletal muscle and liver cells
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The need for stable blood sugar concentrations
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Glucose is essential for providing energy to cells, for maintaining osmotic
balance and for forming major structure components within cells such as
glycoproteins, DNA and RNA
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The pancreas
- The pancreas is a mixed gland composed of both endocrine and exocrine
gland cells
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- Among the acinar cells are approximately a million pancreatic isles (islets
and Langerhans), tiny cell clusters that produce pancreatic hormones
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These cells act as tiny fuel sensors, secreting glucagon and insulin
appropriately during the fasting and fed states
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o Glucagon release is suppressed by rising blood sugar levels and
somatostatin
Beta cells are stimulated to secrete insulin chiefly be elevated blood sugar
levels
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Regulation of blood sugar levels by insulin and glucagon
When blood sugar levels are high, the pancreas releases insulin
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Glucagon, released when blood
sugar levels are low, stimulates glycogen breakdown and thereby raises blood sugar;
that is, glucagon is a hyperglycemic hormone
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Proteins are formed from amino acids linked together by peptide bonds
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Proteins are important for providing structure in the human body
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It is easy for the liver to breakdown amino acids into energy
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They are the
body’s most concentrated source of energy fuel
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- Most dietary fat comes in the form of triglycerides
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- Most saturated fat that we consume comes from animal sources and is
generally regarded as harmful in large amounts because it is ‘sticky’ and ‘furs
up’ the blood vessels (atherosclerosis)
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They have low levels of
viscosity, so not so useful in cooking
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- Hydrogenated fats are the unhealthiest
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The phosphorous containing group gives phospholipids their
distinctive chemical properties
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Steroids
Steroids are flat molecules made of four interlocking hydrocarbon rings
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The most important molecule in our steroid chemistry is cholesterol
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Progesterone
o Found in women – promotes gestation
Testosterone
o Found in men – anabolic steroid – build up muscle and bone mass
Aldosterone
o Produced by the adrenal gland – regulates sodium and potassium in
the blood
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Cortisol
o Same as cortisone
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