Lipids for Jo

Question	Answer
What are LIPIDS?	1 - FATS AND OILS 2 - ORGANIC COMPOUNDS made mostly of CARBON AND HYDROGEN and containing small amounts of OXYGEN
Are Lipids soluble?	They are INSOLUBLE in Water They are SOLUBLE in Organic Solvents such as Acetone, Chloroform and Ether.
How much of the body mass to Lipids represent?	18 to 25%
Lipids can be divided in 3 groups and 5 sub-categories. Which ones?	SIMPLE LIPIDS: Triglycerides (Fats and Oils) COMPOUND LIPIDS: Phosphoglycerides, Sphingolipids, Glycosplingolipids DERIVED LIPIDS: Steroids
What are the building blocks of SIMPLE LIPIDS?	Glycerol and Fatty Acids
How do Glycerol and Fatty Acids come together and what do they form?	They are linked by a CONDENSACTION REACTION that creates an ESTER and Water
How many hydroxyl groups does Glycerol have?	Three
How many Fatty Acids are combined to a molecule of Glycerol in a TAG? What is created from this reaction? Triacyl Glycerol (Triglyceride)	3 Fatty Acids are combined They create 1 Ester and 3 molecules of water
Describe a molecule of a Saturated Fatty Acid and of an Unsaturated Fatty acid	Both have a non polar hydrocarbon chain Both have a polar carboxyl group at one end Saturated FA possess only single bonds in their chain Unsaturated FA possess one or more double bonds in their chain
What is the structural difference between Saturated and Unsaturated FA?	SATURATED FA have straight chains (single bonded) and pack closely together. Solid at room temperature. UNSATURATED FA have bends in their chains (double bonded) and can't pack as closely together. Liquid at room temperature
What kind of Fatty Acid is present in Animals TAGs?	Saturated Fatty Acids they create FATS
What kind of Fatty Acid is present in Plants TAGs?	Unsaturated Fatty Acids they create OILS
Name three functions of the Fatty Acids	- They can be broken down and release energy through oxidation - They can be built up as TAGs and form an energy store - They can be converted into phospolipids and become constituents of the cell membrane
Name four functions of the Triglycerides	- Primary Function: Energy store - they release energy - they produce metabolic water - In Animals they protect vital organs, provide insulation and buoyancy.
Where are the Triglycerides stored?	- in The Adipose Tissue under the skin and around the organs - in the cytoplasm, suspended in droplets
How many tryglicerides can the adipose tissue store?	Unlimited
Use another name for Phosphoglycerides	Phospolipid
How many types of Compound Lipids are there and what are their names?	PHOSPHOGLYCERIDES (Phospolipids) Sphingolipids
What are Phospolipids	They are compound lipids formed of 1 Glycerol, 2 Fatty Acids (non polar) and 1 polar group attached to a phosphate molecule, that can form hydrogen bonds.
How are molecules with both polar and non polar portions called?	AMPHIPATHIC
What happens to the phospate group of most phospolipids?	It is esterified to the hydroxyl group of one of several alcohols, choline, ehthanolamine, glycerol, inositol.
Describe Sphingolipids	Sphingolipids have one Sphingosine backbone that contains an hydrocarbon chain itself, and it connects to one fatty acid via an AMIDE BOND and one phosphate molecule.
What is the main difference between Phospholipids and Sphingolipids?	Phospolipids have a glycerol backbone, Sphingolipids have a sphingosine backbone.
What are Glycolipids?	Glycolipids are derived from Sphingosine, but have one or more sugar residues in place of the phosporylated head group.
Describe Steroids	Steroids have four rings of carbon atoms, and they are more rigid than other lipids. Most steroids are synthetised from cholesterol.
What is Cholesterol?	Cholesterol is a Steroid. it is the metabolic precursor of steroid hormones. It has a large nonpolar region consitgting of the four rings and a hydrocarbon chain.
Name three functions of Cholesterol	As a precursor of the steroid hormones it is a structural component of membranes, precursor to bile acids and an important component of plasma lipoproteins.
What is the basic framework of the plasma membrane around the cells and other making up the organelles?	a Lipid Bilayer
What is the Lipid Bilayer made of?	75% phospholipid 20% cholesterol 5% glycolipid
Why does the bilayer arrangement occur?	Because lipids are amphipathic molecules, the polar hydrophilic heads lie on the outside and the non-polar hydrophobic tails lie on the inside.
What is the role of lipids in the cell membrane?	They act as a barrier to the entry or exit of charged or polar substances. Glycolipids also act as cell-identity markers.
What are the types of proteins found in the plasma membrane?	Integral proteins span the entire width of the bilayer and Peripheral proteins float on the surface of it.
What are the main roles of the proteins in the plasma membrane?	Some Integral proteins act as channels to transport polar molecules, other act as transporters that bind to polar substances and change shape during the transport across the membrane. Some act as cell identity markers or bind to other substances such as hormones.
How is the structure of the plasma membrane known and why?	It is known as the fluid mosaic model, because the proteins are free to rotate and move in their own half of the bilayer.

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	Created by Luca Massaro over 8 years ago