Chapter 5: Lipids Flashcards
Primary Functions of Lipids
Major component of cell membranes (flexibility and integrity)
synthesis of hormones
Concentrated source of energy
Contribute to satiety (feeling full)
Some fats are essential nutrients
Transport and enhance absorption of fat-soluble vitamins A, D, E, and K and phytochemicals
what’s a lipid
Group of compounds made up of carbon, hydrogen, and oxygen
Generally insoluble in water
Diverse in structure and function
types of lipids
fatty acids, triglycerides, sterols, and phospholipids
1cholesterol
2 in cell membranes
3 major energy source
4 most abundant and storage of fat
steroids
phospholipids
fatty acids
triglycerides
Fatty Acids
Consist of a linked chain of carbon atoms with hydrogen atoms attached to each carbon
‒ A methyl group is at one end of fatty acid chain and carboxylic acid group attached at other end
how to differ fatty acid
in chain length and saturation
Determines their function and role in health and disease
Saturation = how many hydrogen atoms fill the available carbon bonds
Saturated Fatty Acids (state at room temp and food source)
Fully hydrogenated
Typically solid at room temperature
Food sources:
Animal products (e.g. meat and dairy)
Tropical oils (e.g. coconut, palm)
Monounsaturated Fatty Acids
One double bond or point of unsaturationin carbonchain
Liquid at room temperature
Plant food sources
Olives, avocados, and some nuts, like peanuts and almonds
Polyunsaturated Fatty Acids
More than one point of unsaturation or more than one double bond
Liquid at room temperature
Food sources:
Most vegetable oils (e.g. safflower, soybean)
Triglycerides (“Fats”)
Three fatty acid chains attached to three carbons on a glycerol molecule
Storage form of fat
Most abundant dietary lipid
Help transport fat-soluble vitamins (A, D, E, K)
storage form of fat and carbs
triglycerides and glycogen
where are fats storage
adipose tissue, heart muscle, skeletal muscle
Sterols
Sterols have four carbon rings and a hydrocarbon side chain
ex: cholesterol
the liver is the site of cholesterol systhesis
TRUE
does cholesterol provide energy?
Is it found on plant food?
NO AND NO
what helps in the process if bile acid, steroid hormones, vitamin D production
cholesterol
Phospholipids
Three-carbon glycerol molecule with two fatty acids and a phosphate group on the third carbon
the unique structural arrangement allows phospholipids to suspend fat in water
Phospholipid Functions
Primary component of cell membranes
Component of lipoproteins that transport lipids in the blood
Lecithin is a phospholipid found in the body as well as in food products
Can be found in egg yolks, liver, and some plant foods
Not an essential nutrient (as body produces sufficient amounts)
Functions as an emulsifier which keeps water and lipids from separating
Lipid Digestion
Limited amount of lipid digestion in mouth and stomach via lipases
Digestion in small intestine facilitated by:
Bile acids (PRODUCED IN THE LIVER FROM CHOLESTEROL)
Emulsification
Pancreatic lipase
MYOCELl
cant move out instine wall and deliver into the interior of mucosa cell
how digestion of lipids takes place in small intestines
bile acids (fa and water soluble sides) attach to lipid globules
lipids are suspend in water and dispersed into smaller droplets
pancreatic lipase digests the triglycerides to monoglycerides and free fatty acids
digested lipids and bile acids are packed into micelles for delivery to the surface of mucosal cells
lipids leave micelle and are absorbed by transporters
lipids are repacked by cell into a chylomicron which move out of the cell and into lymph vessel
enzyme action from pancretic results in
free fatty acids and monoglyceride
lipid transport structure
lipoprotein
the largest and least-dense lipoproten that have the highest amount of triglycerides than cholesterol and transport dietary fats and cholesterol from intestines to muscle and adipose tissue to liver through lymph
chylomicron
a lipoprotein which caries mainly triglycerides from liver to muscle and adipose tissue
VLDL
VLDL synthesis site
liver
VLDL is converted to it, but it primarly carries cholesterol to all cells in the body
“bad cholesterol”
LDL
good cholesterol
bind excess cholesterol and delivers to liver
HDL
calculation and normal range of lipoprotein
170-200
VLDL (30mg/dL) + LDL (100mg/dL)+ HDL (40mg/dL)
Essential Fatty Acids
Must be supplied through the diet
Body cannot synthesize
examples of essential fatty acid (classification)
Linolenic acid (omega-3) and linoleic acid
Both long-chain (omega-6) polyunsaturated fatty acids with 18 carbon molecules
Omega-3 fatty acid—(alpha) linolenic acid and Omega-6 fatty acid—linoleic acid
importance
Required for synthesis of hormone-like compounds (eicosanoids)
EPA vs DHA
eicosapentaenoic acid and docosahexaenoic acid
what is use of trans fat
Makes it more solid at room temperature and more stable (more resistant to becoming rancid)
how reactions produces trans fat
partial hydrogenation of polyunsaturated fats
what’s the AMDR for fat
20% to 35%
