Transcript carbs and lipids

BIOMOLECULES
• You are what you eat:
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CARBOHYDRATES
LIPIDS
PROTEINS
NUCLEIC ACIDS
Carbohydrates
MONOSACCHARIDES
• All have the
formula (CH2O)n
• The most common
and
important
monosaccharide is
glucose, which is
a six-carbon or
hexose sugar, so
has the formula
C6H12O6.
• Glucose is the most abundant organic
compound in nature.
• Reactions of cellular respiration
transform glucose into ATP energy.
• Most important sugar in our diet
• Diabetics lack hormone insulin, which
allows glucose to enter into cells to be
used in mitochondria.
• There
are
many
isomers of glucose,
(same chemical formula
but different structural
formulae).
• These isomers include
fructose and galactose.
• Fructose:
found
in
honey,
tree
fruits;
berries; melons; and
some root vegetables,
such as beets, sweet
potatoes, parsnips and
onions
• Galactose: found in dairy products, in sugar
beets and gums. Galactose is less sweet than
glucose and not very water-soluble.
• Humans do not have the enzymes needed to
use galactose directly. It must be converted
into glucose first.
Disaccharides
• Sugars that consist of two monosaccharides,
joined by a glycosidic bond.
• Examples are: maltose (glucose-glucose),
sucrose (glucose-fructose), and lactose
(galactose-glucose)
• The formation of a glycosidic bond involves
the formation of water as a by-product and
is a dehydration synthesis reaction. (aka:
condensation reaction)
Polysaccharides
• Large carbohydrate chains made up of more
than 10 subunits.
• Are a way of storing glucose until it is
required – starch in plants and glycogen in
humans
• Also structural role: cellulose makes up
plant cell wall
LIPIDS
• Diverse group: fats, phopholipids,steroids,
and waxes
• Structurally: are not made up of repeating
sub units.
• Common Properties:
– they are all hydrophobic and do not
dissolve in water
– They all contain hydrogen, oxygen and
carbon
4 types of lipids:
1.Fats –aka Triglycerides
– long term energy
storage.
– concentrated source of
energy- 1 g of fat has
more than twice the
energy of 1 g of
carbohydrate
– Also cushion organs and
insulate
• Structure of fats: 3 fatty acids + glycerol =
triglyceride
• Formed by dehydration synthesis reaction
• Fatty acids have long hydrocarbon chains
with a carboxyl group at one end.
• Saturated fatty acids can lie closely
together and form weak Van der Waal
bonds between molecules. They are solids
at room temperature. They are usually
animal fats.
• Unsaturated fats are loosely packed
because of the kinks in the hydrocarbon
chain. They are oils at room temperature,
and are usually from plants.
• Trans-fatty acids: “the hidden fats”
– are produced when hydrogen is added to
unsaturated fats. (Hydrogenation)
– Trans fats are solids at room temperature
– Trans fats cause significant and serious
lowering of HDL (good) cholesterol and a
significant and serious increase in LDL (bad)
cholesterol; make the arteries more rigid; cause
major clogging of arteries; cause insulin
resistance; cause or contribute to type 2
diabetes, and heart disease.
– Now mandatory labeling of amount of trans
fats in Canada. ( December 12, 2005)
• Phospholipids: are part of cell
membrane. They help to regulate what
substances can enter cells and which can’t.
• Steroids: cholesterol ( important in cell
membranes), hormones such as testosterone and
estrogen.
• They all have a 4 ring structure
• Waxes: are formed from fatty acids and
long-chain alcohols. They are
commonly found wherever
waterproofing is needed, such as in leaf
cuticles, insect exoskeletons, birds'
feathers and mammals' fur.