NUTRTION 445
EXAM 3 - STUDY GUIDE
Know the different categories of lipids important in human nutrition.
- Fatty acids
- Triacylglycerol
- Sterol & Steroids
- Phospholipids
- Glycoplipids
- Lipoprotein
Know the basic structures of saturated and unsaturated fatty acids, triacylglycerol, cholesterol and
phospholipid. (Be able to recognize them if given a diagram)
Saturated
- Myristic Acid (14:0)
- Palmitic Acid (16:0)
- Stearic Acid (18:0)
- Arachidic Acid (20:0)
- Lignoceric Acid (24:0)
Unsaturated Fatty Acid
- Palmitoleic Acid (16:1 delta 9)
- Oleic Acid (18:1 delta 9)
- Linoleic Acid (18:2 delta 9,12)
- Alpha-linoleic Acid (18:3 delta 9,12,15)
- Arachadonic Acid (20:4 delta 5,8,11,14)
What is the difference between cholesterol and a cholesterol ester?
- Cholesterol Esters, derivatives of cholesterol, have an ester bond is formed between the
carboxylate group of a fatty acid and the hydroxy. It undergoes hydrolysis to free cholesterol
and a fatty acid. When its esterfied it is more stable in the cytoplasm
- Function : Cholesterol plays a major role in the metabolic functions and hormone productions
and transported to the cells through the bloodstream to perform its function. Cholesterol esters
aids the cholesterol in the absorption of cholesterol so it is properly delivered to the cells.
Know fatty acid nomenclature (delta and omega system).
- Delta : start counting from the carboxyl carbon
- Omega: start counting from the methyl end
What 3 desaturases do humans have?
- Humans are incapable of forming double bonds beyond the delta-9 carbon in the chain.
o Delta – 9, 6 and 5
What are the primary saturated fatty acids that can increase CVD risk?
- Myristic, palmitic and lauric acids, raise the LDL-C levels, which increases CVD risk
Know major polyunsaturated fatty acids and their main functions.
- Alpha-linoleic Acid (18:3)
- Eicosepentaenoic acid (20:5)
- Docosahexaenoic acid (22:6)
Know the essential fatty acids and the fatty acids that can be derived from essential fatty acids.
- Arachoidonic Acid can be synthesized from Linoleic Acid
- EPA and DHA can be made from alpha linolenic acid
What are the dietary sources of SFA, MUFA and PUFA?
- MUFA : Canola oil, olives, olive oil, peanuts, peanut oil, and nuts such as pecans, almonds
- PUFA : sunflower oil, walnuts, fish products, french dressing
- SFA: animal fat, vegetable oils, palm and canola oils
What are the main functions of cholesterol?
- A subcategory of sterols
- Serves as precursor for many steroids in the body (bile acids estrogen,androgen, Vitamin D)
Know the 4 different kinds of phospholipids based on their base group. (Slide 21 -10/22)
, - Phosphatidyl Choline
- Phosphitidyl Serine
- Phosphatidyl inositol (used for signaling inside the cell)
- Phospatidyl ethanolamine
What is the relationship between fatty acid content and membrane fluidity?
- Double bond = less membrane fluidity
What is lecithin?
- An enzyme(LCAT) that forms cholesterol esters by catalyzing the transfer of fatty acids to free
cholesterol within an nascent HDL particle
What is the function of the following phospholipases: PLA, PLA2, PLC or PLD?
- Phospholipases : help break down in the gut and eventually becomes a part of the chylomicron.
- PLA2- made by the pancrease and hydrolyzes dietary and biliary phospholipids. It tagets sn-2
position of glycerol
-
Know the major apolipoproteins (A1, A2, A4, B100, B48, C2, E) and their functions.
- A1 : activator for Lecithin Cholesterol acyltransferase
- A4 : secreted with chylomicrons by transferred to HDL
- B100 : Ligand for LDL receptor
- B48 : chylomicrons , synthesized in intestines
- C2 : activator of lipoprotein lipase
- E: synthesized in liver, added to HDL and then transferred to VLDLs
Describe the role of the liver and adipose tissues in lipid metabolism
Role of liver
- The liver synthesizes bile salts (cholesterol metabolism), lipoproteins, and new lipids from
nonlipid precursers (de novo lipogenesis)
- Mobilizes triglycerides
Role of adipose
- Store triacylglycerides from chylomicrons and VLDL after lipoprotein lipase action
- Metabolism of triacylglycerol during fasting
- Adipocytes carry out lipolysis and release FA into the blood
-
What lipid profiles are positively or negatively correlated with CVD?
- HDL – negative
- Positive – LDL, VLDL, Triacylglycerides
What are the mechanisms by which saturated and unsaturated fatty acids influence CVD?
- Long-chained fatty acids (Saturated and Unsaturated) increase the risk of CVD since they are
all hypercholesterolemic, increasing the levels of total cholesterol or LDL-C levels
What are the mechanisms by which trans fatty acids impact CVD risk?
- Trans fatty acids lower HDLs and increase LDLs and the impact on CVD is greater than
saturated and unsaturated fatty acids
What are the mechanisms by which n3 fatty acids affect CVD?
Understand chylomicron and VLDL metabolism.
- Chylomicrons
o Formed from TAGs, 1st enters the lymphatic vessels, then bloodstream, broken down
into FFA and DA by lipoprotein lipase, which is absorbed by the tissue cells. Then, it
goes back to the liver as chylomicron remnents by hepatic lipase
- VLDLs
o TAG is broken off by lipoprotein lipase, which uses ApoC-2 for the interaction. After
TAG is broken off, IDL and then LDL (cholesterol rich). ApoC-2 activates lipoprotein
lipase
EXAM 3 - STUDY GUIDE
Know the different categories of lipids important in human nutrition.
- Fatty acids
- Triacylglycerol
- Sterol & Steroids
- Phospholipids
- Glycoplipids
- Lipoprotein
Know the basic structures of saturated and unsaturated fatty acids, triacylglycerol, cholesterol and
phospholipid. (Be able to recognize them if given a diagram)
Saturated
- Myristic Acid (14:0)
- Palmitic Acid (16:0)
- Stearic Acid (18:0)
- Arachidic Acid (20:0)
- Lignoceric Acid (24:0)
Unsaturated Fatty Acid
- Palmitoleic Acid (16:1 delta 9)
- Oleic Acid (18:1 delta 9)
- Linoleic Acid (18:2 delta 9,12)
- Alpha-linoleic Acid (18:3 delta 9,12,15)
- Arachadonic Acid (20:4 delta 5,8,11,14)
What is the difference between cholesterol and a cholesterol ester?
- Cholesterol Esters, derivatives of cholesterol, have an ester bond is formed between the
carboxylate group of a fatty acid and the hydroxy. It undergoes hydrolysis to free cholesterol
and a fatty acid. When its esterfied it is more stable in the cytoplasm
- Function : Cholesterol plays a major role in the metabolic functions and hormone productions
and transported to the cells through the bloodstream to perform its function. Cholesterol esters
aids the cholesterol in the absorption of cholesterol so it is properly delivered to the cells.
Know fatty acid nomenclature (delta and omega system).
- Delta : start counting from the carboxyl carbon
- Omega: start counting from the methyl end
What 3 desaturases do humans have?
- Humans are incapable of forming double bonds beyond the delta-9 carbon in the chain.
o Delta – 9, 6 and 5
What are the primary saturated fatty acids that can increase CVD risk?
- Myristic, palmitic and lauric acids, raise the LDL-C levels, which increases CVD risk
Know major polyunsaturated fatty acids and their main functions.
- Alpha-linoleic Acid (18:3)
- Eicosepentaenoic acid (20:5)
- Docosahexaenoic acid (22:6)
Know the essential fatty acids and the fatty acids that can be derived from essential fatty acids.
- Arachoidonic Acid can be synthesized from Linoleic Acid
- EPA and DHA can be made from alpha linolenic acid
What are the dietary sources of SFA, MUFA and PUFA?
- MUFA : Canola oil, olives, olive oil, peanuts, peanut oil, and nuts such as pecans, almonds
- PUFA : sunflower oil, walnuts, fish products, french dressing
- SFA: animal fat, vegetable oils, palm and canola oils
What are the main functions of cholesterol?
- A subcategory of sterols
- Serves as precursor for many steroids in the body (bile acids estrogen,androgen, Vitamin D)
Know the 4 different kinds of phospholipids based on their base group. (Slide 21 -10/22)
, - Phosphatidyl Choline
- Phosphitidyl Serine
- Phosphatidyl inositol (used for signaling inside the cell)
- Phospatidyl ethanolamine
What is the relationship between fatty acid content and membrane fluidity?
- Double bond = less membrane fluidity
What is lecithin?
- An enzyme(LCAT) that forms cholesterol esters by catalyzing the transfer of fatty acids to free
cholesterol within an nascent HDL particle
What is the function of the following phospholipases: PLA, PLA2, PLC or PLD?
- Phospholipases : help break down in the gut and eventually becomes a part of the chylomicron.
- PLA2- made by the pancrease and hydrolyzes dietary and biliary phospholipids. It tagets sn-2
position of glycerol
-
Know the major apolipoproteins (A1, A2, A4, B100, B48, C2, E) and their functions.
- A1 : activator for Lecithin Cholesterol acyltransferase
- A4 : secreted with chylomicrons by transferred to HDL
- B100 : Ligand for LDL receptor
- B48 : chylomicrons , synthesized in intestines
- C2 : activator of lipoprotein lipase
- E: synthesized in liver, added to HDL and then transferred to VLDLs
Describe the role of the liver and adipose tissues in lipid metabolism
Role of liver
- The liver synthesizes bile salts (cholesterol metabolism), lipoproteins, and new lipids from
nonlipid precursers (de novo lipogenesis)
- Mobilizes triglycerides
Role of adipose
- Store triacylglycerides from chylomicrons and VLDL after lipoprotein lipase action
- Metabolism of triacylglycerol during fasting
- Adipocytes carry out lipolysis and release FA into the blood
-
What lipid profiles are positively or negatively correlated with CVD?
- HDL – negative
- Positive – LDL, VLDL, Triacylglycerides
What are the mechanisms by which saturated and unsaturated fatty acids influence CVD?
- Long-chained fatty acids (Saturated and Unsaturated) increase the risk of CVD since they are
all hypercholesterolemic, increasing the levels of total cholesterol or LDL-C levels
What are the mechanisms by which trans fatty acids impact CVD risk?
- Trans fatty acids lower HDLs and increase LDLs and the impact on CVD is greater than
saturated and unsaturated fatty acids
What are the mechanisms by which n3 fatty acids affect CVD?
Understand chylomicron and VLDL metabolism.
- Chylomicrons
o Formed from TAGs, 1st enters the lymphatic vessels, then bloodstream, broken down
into FFA and DA by lipoprotein lipase, which is absorbed by the tissue cells. Then, it
goes back to the liver as chylomicron remnents by hepatic lipase
- VLDLs
o TAG is broken off by lipoprotein lipase, which uses ApoC-2 for the interaction. After
TAG is broken off, IDL and then LDL (cholesterol rich). ApoC-2 activates lipoprotein
lipase
