Lipids And Membranes Flashcards
What are the generalized concepts of Fatty Acid?
-monocarboxylic
-linear
-even number of C
-unsaturated
-cis (naturally occurring), trans (produced by hydrogenation)
Properties of Fatty Acid
-Pka- 4.5 ~ 5.0
-Melting point
—- increases with longer chain length
—- decreases as number of double bonds increases
-Solubility- fatty acid with up to C6 and then only in non polar solvents
- Amphipatic
- structure - formation of micelles.
How is the hydrophobic affect achieved ?
The fatty acids are amphipathic. The hydrophilic head interacts with water and the hydrocarbons interact with each other via vdw forces minimizing the contact with water
Similar to carbohydrates, what are the two main functions of lipids
Starage and membrane lipids (lipids)
CARBOHYDRATES;
Structure
Storage
Energy transport
Information
What are the different types of storage lipids and membrane lipids?
Storage lipids - triglycerides
Membrane lipids - Glycerophospholipids, sphingolipids
What does triglycerides measn
1 glycerol with 3 fatty acids
Fatty acids are also called ( fatty acyl units)
Therefore triglycerides can also be called
Triacylglycerol
Properties of triglycerides
1- melting point varies similar to other lipids
2- most abundant of all lipids
3- insulation - adipocytes cells under skin
4- energy storage in fat cells, seeds
5-buoyancy- lipids are less dense then water, oil density changes with temperatures
6- releases 2x more energy
Why does lipids /triglycerides provides 2x more energy then carbohydrate?
More H in lipids - eg the tail of fatty acid
And triglycerides have 3 tails
What is the difference between fat and lipids
Lipids are liquid at room temperature
Fats are solid at room temperature
Why are oils liquid at Rtp?
Low melting point
Meaning they have shorter chains or more double bonds
Because they are highly unsaturated
Why does more double bonds decreases melting point when it should be the other way around?
More double bonds dec melting point because
1- we learnt that naturally occurring/ usually the lipids have cis bonds
2- cis bond dec the intermolecular interactions , less energy required to break bonds therefore lower melting point
3- cis bonds make it difficult to closely/ tightly pack the FA
What is saponification
Saponification is the process of forming soap
Write down the equation of soap making
Describe the process of saponification.
Lipases hydrolyze the TAC
The R grouos attracted to do dirt and grease
The polar O and Ka will drag it into water
Micelles forms , containing dirt
Membrane lipids- Glycerophospholipids are derivatives of ?
Phosphatidic acid
There can be variations in the Glycerophospholipids, which are derivatives of Phosphatidic acids, by varying its head molecule. What are the 3 types of Glycerophospholipids that can form?
Phosphatidylethanolamine
Phophatidylserine
Phosphatidylcholine (Lecithin)
Draw these three types of Glycerophospholipids.
Which type of Glycerophospholipids forms a bilayer in water and is a part of cell membrane?
Phosphatidyl choline
Name the saturated lipid chains
ACLPS
2, 10, 12, 16, 18
Acetic
Capric
Lauric
Palmitic
Steric
What are steroids
Lipids containing 4 fused rings
Steroid nucleus
Made of 4 rings- 3 with 6 carbons and one ring with 5 carbons
Almost planar and conformationally rigid
Sex hormones , bile salts and some poisons
Made of isoprene
What are the two types of steroids
Structural
Non structural
Name the structural steroids
Cholesterols
Explain cholestrol
Polar oh at c3
Aliphatic 8 carbon chain at c17
Part of membrane (35% of total lipid)
Cholestrol is stored and transported as ————-
As cholesteryl esters - the cholestrol is esterfied to the fatty acid chain ( c8)
Why is cholesterol stored and transported as cholesteryl esters?
Become more hydrophobic for storage and transport in lipoprotein complexes
How does the density pf lipoproteins decrease?
The density of lipoprotein coat is greater then the density of the core
The larger the core, the lower the density
What are the four types of lipoproteins?
1- chylomicrons
2- VLDL
3-LDL
4-HDL
Which of these are bad cholestrols
Chylomicrons , VLDL, LDL
Transported from liver , intestines to tissues
Why are these lipoproteins bad ?
As they transport , they spread the excess everywhere
This Leads to clogging of arteries, causing heart disease
Good cholestrol
HDL
from tissues to liver and intestine
What are the non structural steroids?
Testosterone
Estradiol
Not in membrane
What is the function of phospholipid bilayer membrane?
Define cell boundaries
Regulates traffic
Compartmentalize internal space
Organize complex reaction seq
Imp for energy conservation and cell to cell communication
Fluid mossaic model
- lipids are arranged in a bilipid structure where the hydrophobic tails are inside and the hydrophilic heads are out
- the lipids in the membrane are not static and continiously moving
-The flexibity and fluidity of membrane keeps changing based on fa tails and cholestrol
REDUCE FLEX
—- high content of cholestrol
— saturated fatty acid tails -less double bonds - lessflexible - the two mono layers are different from each other
- the inside is also different from outside
There are two types pf proteins involved in membrane . Name them and compare and contrast them
Peripheral -
- dont move
- bound electrostatically or
- bound covalently
- electrostatic-ally bound proteins Released by high salt concentration
Integral -
Move and diffuse laterally in the PLANE of the blipped layer ( just like lipids)
Removed by organic extraction or detergent
What are the function of membrane proteins?
Structural - holds the lipod bilayer together
Dynamic
- tranport proteins ( pump / carriers/ permease)
Receptor proteins( antigens )
Enzymes
Others
