CC - LIPIDS Flashcards
are large molecules made up of elements – C, H, O
Fats or Lipids
Fats or Lipids are large molecules made up of elements – _, _, _
C, H, O
Fats/Lipids Hydrogen to Oxygen ratio is higher than __
2:1
Due to such a _________, ____ contains more energy storing carbon hydrogen bonds than _________
molecular arrangement ; fat ; carbohydrate
_____ are non-polar, insoluble molecules, So they are perfect _______ .
Fats ; storage molecules
Thus our body converts all the excess ______ taken through’ diet into ____.
sugar ; fat
Oils and fats are made up of more than one component.
- Glycerol
- Fatty acids
_____ is a 3 carbon molecule each with a hydroxyl group (-OH).
Glycerol
forms the backbone of fat molecule.
3 carbon molecule
Fatty acids are long chains with only _____ and ______ in a chain and at the end there will be another group, _______
carbon ; hydrogen ; carboxyl group ( -COOH)
Roles of Lipids
- Source of energy
- Integral part of cellular membranes that assist in cell structure
- Converted to hormones or hormone precursors
- Insulators for nerve conduction and heat retention
Classification of Lipids
Simple
Compound
FA’s esterified with glycerol
Simple Lipids
same as simple, but with other compounds also attached
Compound Lipids
fats containing phosphoric acid and nitrogen (lecithin)
Phospholipids
FA’s compounded with CHO, but no N
Glycolipids
substances from the above (simple and compound) derived by hydrolysis
Derived Lipids
large molecular wt. alcohols found in nature and combined w/ FA’s (e.g.cholesterol)
Sterols
the _____ of a lipid have no double bonds between carbons in chains they are tightly packed (like building a wall with bricks)
SFA’s - saturated fatty acid
stearic melts at ____ clog arteries as ______
70oC ; atherosclerosis
more than one double bond in the chain because of double bonds PUFA do not pack well.
Polyunsaturated Fatty Acids
most common polyunsaturated fats are _____, _____ and _______.
oleic, linoleic, and linolenic acid
oleic melts at ____
26oC
unsaturated fats have lower ______, ______ objects
melting points ; irregular-shaped
Linear chain of C-H bonds
Fatty Acids
Fatty acids terminate with a ______ group
carboxyl
Fatty acid is an integral part of _________
triglycerides/phospholipids
Body makes most ______ and _______ store large amounts of energy
fatty acids ; fatty acids
Essential fatty acids
linolenic and linoleic acid
Fatty acid is Acquired by ____
diet
Composed of 3 fatty acid molecules, which includes glycerol
Triglycerides
Triglycerides is ______ = water insoluble
Hydrophobic
Triglycerides comprises _____ of fat stored in tissue
95%
Come from the diet - Plant or animal sources
Exogenous
Synthesized by the body
Endogenous
Composed of 2 fatty acid molecules
Phospholipids
Phospholipids is ______ meaning has both hydrophilic and hydrophobic parts
Amphipathic
Phospholipids is found on surfaces of _______.
lipid layers
Phospholipids is synthesized in the ______
liver
Synthesized in animals, plants, our bodies
Cholesterol
Functions of Cholesterol
- Promotes fat absorption in intestine via bile acids
- Produces some hormones
- Transforms Vitamin D in the skin
- Component of cell membranes (Amphipathic)
Originates in animal products
Exogenous
Exogenous is also absorbed via _____ secretions, _____ secretions, and turnover of __________
biliary ; intestinal ; intestinal mucosal cells
Produced in the liver and intestine from acetyl-CoA
Endogenous
General Structure of Lipoproteins
- Size of the molecule correlates with lipid content
- Composed of both lipids and proteins
- Outer layer of proteins called the apolipoprotein
Size of the molecule correlates with ______ content
lipid
Lipoprotein is composed of both _____ and _______
lipids ; proteins
In lipoprotein, outer layer of proteins called the ________
apolipoprotein
Five categories of Lipoprotein
- Chylomicrons
- VLDL
- IDL
- LDL
- HDL
Largest and least dense of the lipoproteins
Chylomicron
Lipid-rich transport vessel that carries triglyceride in circulatory system to cells
Chylomicron
Chylomicron is observed as a _____ layer in a samle
creamy
very low density lipoproteins
VLDL
Carry triglycerides to cells for energy use and storage
VLDL
VLDL is ____ made
liver
VLDL specimen appears ______ in fasting samples
turbid
High density lipoproteins
HDL
Gather excess cholesterol and return them to liver
HDL
HDL is made in _____ and ______
liver and intestine
Low-density lipoproteins
LDL
Deliver cholesterol to peripheral cells and liver following triglyceride removal
LDL
Function of Apolipoproteins
- Maintain structural integrity
- Binding site for cell receptors
- Activator/Inhibitor of various enzymes
TYPES OF APOLIPOPROTEINS
APO A-I
APO B
APO C
APO E
Major protein on HDL
APO A-I
Principal protein LDL, VLDL and chylomicrons
APO B
APO B TWO FORMS
B-100 AND B-48
Activates lipoprotein lipase (LPL) to break down triglycerides
APO C
Promotes binding of LDL, VLDL
APO E
Three pathways
- lipid absorption
- exogenous
- endogenous
3 pathways depend on ______ lipoprotein particles
apo-B
3 pathways transport _______ and ________ to peripheral cells
dietary lipids ; hepatic-derived lipids
3 pathways critical transport mechanism of _____ to peripheral cells
fatty acids
the fourth pathway
Reverse cholesterol transport
Maintains cholesterol equilibrium
enzymes involved in digestion of lipids
Lingual Lipase
Pancreatic Lipase
Colipase
Lipid Esterase
Phospholipases
provides a stable interface with aqueous environment of stomach
Lingual Lipase
major enzyme affecting triglyceride hydrolysis
Pancreatic Lipase
protein anchoring lipase to the lipid
Colipase
secreted by pancreas, acts on cholestrol esters, activated by bile
Lipid Esterase
cleave phospholipids, activated by trypsin
Phospholipases
they form the spherical structures (micelles) assisting in absorption
bile
hydrophobic portion (______) are located to the inside of the micelle, with _______ (hydrophillic portion) to the outside
tails of FA ; heads
Biles move lipids from the ________ to the _______
intestinal lumen ; cell surface
in bile, absorption is by ______ (complete for FA and monoglycerides, less for others)
diffusion
short chain FA’s are absorbed and enter the portal ____ to the _____
vein ; liver
those FA’s with more than 10 carbons are resynthesized by the ____ to _______
liver ; triglycerides
they (FA’s) are then converted into ______ and pass to the _____
chylomicrons ; lymphatic system
some FA’s entering the liver are ______ for energy, others ______
oxidized ; stored
blood lipids:
45% P-lipids
35% triglycerides
15% cholestrol esters
5% free FA’s
During digestion, ______ cuts off fatty acids and converts dietary lipids to compounds with _______ properties
pancreatic lipase ; amphipathic
_______, ________ and ________ are also transformed to amphipathic lipids
Triglycerides, phospholipids and cholesterol esters
These lipids form aggregates with bile acids in the intestine-called _______
micelles
Absorption occurs when ______ contact membranes of the _______ cells
micelles ; intestinal mucosal
Short chain fatty acids, enter circulation, picked up by ______, taken to ______
albumin ; liver
Long chain fatty acids, monoglycerides, diglycerides Re-esterified in intestinal cells to form ______ and _______
triglycerides ; cholestyl esters
