lipids Flashcards
are lipids water soluble?
why are they not considered polymers?
no
Lipids are not considered polymers because they do not consist of repeated monomer units linked together through covalent bonds, which is a defining characteristic of polymers. Instead, lipids are a diverse group of organic molecules that have unique and variable structures.
polymers
a uniform repetition of monomeric units.
what are the main biological functions of lipids?
Energy storage
Heat/Insulation
Structural components of cell membrane communication
name the types of lipids
Fatty acids
Triacylglycerols
Phospholipids
Sphingolipids
Steroids
what is the general formula for fatty acids?
what do we mean when we say fatty acids are amphipathic?
H(CH2)nCOOH
means they have both hydrophilic and hydrophobic regions
what is the typical range for the number of carbons in fatty acid chains that are found in plants and animals?
between 16 and 18
by what means are lipids mostly circulated around the body
by being bound to albumin
what are fatty acids found at high levels in the plasma during fasting?
The increase in fatty acids in the plasma during fasting is directly connected to the process of lipolysis. Lipolysis is the biochemical process by which stored triglycerides (fat) in adipose tissue are broken down into their constituent fatty acids and glycerol. These released fatty acids are then released into the bloodstream, leading to higher plasma levels of free fatty acids (FFAs) during fasting. this helps to produce energy
features of saturated fatty acids
they have only single bonds between their carbons
they have a linear appearance
they are solid at room temperature
features of unsaturated fatty acids
One or more C=C bonds
They have C=C double bonds that give distinct bend
Reduces Tm(melting point), therefore, they are liquid at room temp
what effect does a low saturation have on the melting point of fatty acids
it results to a low melting point
Describe the composition of triglycerides(triacylglycerols) (TAGs)
Glycerol head group attached to 3 fatty acid chains
how are TAGs stored?
they are stored as cytoplasmic lipid droplets
enzyme that hydrolyses lipids into glycerol and 3 fatty acids
lipase
homogenic fatty acids
heterogenic fatty acids
fatty acids of the same structure
fatty acids of different structures
saturated fats
example
fats composed of saturated fatty acids
most animal fats
examples of unsaturated fats
plant and fish fats (aka oils)
where in mammals are fats stored?
in the adipose tissue
which stores more energy, carbohydrates or fats
fats store double the amount of energy that carbohydrates store
composition of phospholipids
glycerol, two fatty acids and a phosphate group
sphingolipid composition
sphingosine, one fatty acid, and an R-group
functions of sphingolipids
Cell recognition
Cell Signaling
Lipid rafts
steroids
Steroids are lipids with a common carbon skeleton consisting of four fused carbon rings
what results to there being different steroids
different functional groups being attached to the rings
what is the base for all steroid hormones and bile acids
cholesterol
name some steroid hormones
cholesterol
Oestrogen
testosterone
progesterone
Glucocortecoids
where in the mammalian system is cholesterol synthesized
the liver
what is the total average body composition of cholesterol?
what percentage of this is part of the cell membrane structure
150g
90 percent
lipid transport is undertaken by
apolipoproteins
briefly describe lipid transport
Dietary lipids are transported from the intestine to the liver (exogenous)
Lipids are then transported from the liver to peripheral tissues (endogenous)
what are the classes of lipoproteins?
Chylomicron
VLDL(Very Low-Density Lipoproteins)
LDL(Low-Density Lipoproteins)
HDL(High-Density Lipoproteins)
which one of the classes of lipoproteins has the lowest density(i.e low protein: lipid ratio)
chylomicrons
which one of the classes of lipoproteins has the highest weight of triacylglycerols
chylomicrons
which one of the classes of lipoproteins has the second highest triacylglycerols as % of weight
VLDL
glyceride
type of lipid composed of glycerol and fatty acids
