PHYSCI 5 Lecture 10: PHYSCI 5 Week 4 A
■Lipids have vital functions and are commonly known as fats
■Their intake should be monitored and while they can be beneficial, these should
be avoided
■They can be triglycerides and fatty acids , phospholipids and cholesterol and the
2 forms of lipids in food are oils and fats
■Oils are liquid at room temp
■Fats are solid at room temp
■They are water insoluble and hydrophobic - things are water soluble are
hydrophilic
■Types of lipids
■Triglycerides
■Most common that we consume in our diet
■Made of 1 glycerol and 3 fatty acids (this part is not soluble )
■Glycerol is sugar alcohol
■Fatty acids are unique in structure and function and based on
saturation
■Fatty acids are unique because of their storage and
metabolism
■Triacylglycerols
■Length
■Size determines how it can be metabolized - the
number of carbon atoms can be done in two ways -
through the carbon of the carboxyl group - alpha carbon
- or counted from the last carbon on the opposite end -
omega carbon
■Length determines rate of absorption and digestion
■The length is
●Short chain - less than 6C
●Medium chain - 6-12
●Long chain 12+
■Level of saturation
■Long chains of carbon atoms connected together by
covalent bonds
●Fatty acid is saturated if all bonds are connected
to H
●If there is 1 double bond it is monounsaturated
●Unsaturated are liquid at room temperature
○Less surface area and aggregate less d
are corn oil and safflower oils
○Plant fat
■Olive oil and canola oil and
peanut oil are high in
monounsaturated fatty acids
and are liquid
■Polyunsaturated
●Saturated are solid at room temperature due to
change in the shape of the molecule
○Saturated have more surface area and
aggregate together to be solid at room
temp
○Animal fat
■2 different shapes of fatty acids - cis and trans
●Cis - bulky groups are on the same sides
○Bend and kinks and has less surface
area that does not form bonds with
neighbors and low interactions
○Found in lots of vegetable oils
●Trans - bulky groups on opposite sides
○High surface area and solid
■Beneficial CIS>trans
■Trans increases amount of cardiovascular diseases
■Dairy has minor amounts of trans fat
■Very popular in food production because they are stable
and give longer shelf life and prevent tancidity and
added to many cakes and cookies
■Hydrogenation
●Food companies synthesize this because it's not
very prominent in nature
●Higher risk of cardiovascular diseases,
hypertension and type 2 diabetes
■Essential fatty acids in triglycerides
■Cis fatty acids are important to consume in the diet
■Cis fatty acids are unsaturated - at least one double
bond in carbon chain
■The double bond cannot be placed before the ninth
carbon from the omega carbon
■Essential fatty acids are important in growth and clot
prevention and decrease risk of heart diseases
●Most common is eicosanoids - eicosa = 20 in
greek because they are made from fatty acid
that are 20 carbons in length and produced
many in cells as prostaglandins, thromboxanes
and leukotrienes and function as blood clot
prevention, smooth muscle regulation in blood
vessels and digestive organs and immune
functions
●Omega 3 - alpha linolenic acid
○Cannot be made in the body
■In leafy greens, flax seeds,
walnuts and fish
■Epa and DHA fund in salmon
and tuna
■EPA and DHA assoc with
lowering cardiovascular disease
risk
●Omega 6 linoleic acid
○Cannot be made in the body
○Found in soy, vegetable nuts like
sunflower, forn, soy and peanut oils
○Too much omega 6 will become
inflammatory and so cannot be high
■Types of Lipids, phospholipids
■Amphipathic whether one part is water soluble and the other is water
insoluble
■Found in many foods - egg yolk lecithins and peanuts are are used as
additives because of unique amphipathic property that make food more
blended
■Listed as emulsifiers
■Similar in structure to triglycerides and have 3 molecules plus one
glycerol and made of 1 lrl and 2 fatty acid molecules and one phosphate
containing groups
■The phosphate difers
■Water soluble generally and constitute the plasma membrane
of cells used to transport molecules to the blood and important
in lipid digestion
■Not essential because they can be made in our cells
■Types of Lipids: Sterols
■Multi Ring structure and found in plants and animals and made in
bodies
■Plant sterols are not well absorbed in our digestive system and actually
decrease absorption of animal sterols
■Animal cholesterol in the diet is in the form of ester cholesterol
and easily absorbed
■Cholesteryl ester have fatty acid chain attached to ring
structure
●Most common dietary cholesterol
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PHYSCI 5 Full Course Notes
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Document Summary
Lipids have vital functions and are commonly known as fats. Their intake should be monitored and while they can be beneficial, these should be avoided. They can be triglycerides and fatty acids , phospholipids and cholesterol and the. 2 forms of lipids in food are oils and fats. They are water insoluble and hydrophobic - things are water soluble are hydrophilic. Most common that we consume in our diet. Made of 1 glycerol and 3 fatty acids (this part is not soluble ) Fatty acids are unique in structure and function and based on saturation. Fatty acids are unique because of their storage and metabolism. Size determines how it can be metabolized - the number of carbon atoms can be done in two ways - through the carbon of the carboxyl group - alpha carbon. Or counted from the last carbon on the opposite end - omega carbon. Length determines rate of absorption and digestion.