Lipids Flashcards
(24 cards)
5 classes of lipids
- fatty acids
- triacylglycerol (TAG)
- phospholipid
- glycolipid
- steroids
consequences of essential fa deficiency
growth retardation reproductive failure kidney and liver disorders depression ADHD
usually associated with intestinal absorption disorders
micelles define
when ampiphatic lipids have their hydrophobic heads on the inside and tails on the outside and form a soluble capsule. assist large chain FAs in entering the cell l
lipoproteins define
soluble proteins that combine with and help transport fats
- hydrophobic molecules inside like TAG, CE (cholesterol esters)
- hydrophilic molecules outside like PP lipids, unesterified cholesterol, apolipoproteins
types of chylomicrons
a type of lipoprotein
- VLDL (very low density - lipids»_space; proteins)
- LDL (low den - lipids > proteins)
- HDL (high den)
VLDL
produced in the liver
carries TAG, CE, cholestrol to peripheral tissues
LDL
is converted from IDL, which is VLDL after TAG has been released
delivers CE and cholesterol to peripheral tissues
too much LDL in the blood will lead to obesity and atheoscelerosis
HDL
removes excess cholesterol from the cell and return it to liver for elimination and for bile and hormone synthesis
malonyl coa define
inhibits CPT I and II and prevents entry of long chain fa into mitochondrial intermembrane space and matrix
CPT I deficiency
affects the liver
causes coma when fasting because b oxidation cannot occur and body relies on liver for glucose supply
CPT II deficiency
affects skeletal and cardiac muscle, causes muscle weakness
peroxisomes function
small organelles in cell cytoplasm that reduced long chain C atoms before entering the mitochondria
examples of ketones
acetone
acetoacetate
3 - hydroxybutyrate
3 main characteristics of ketone bodies
- soluble in blood, does not bind to lipoprotein or albumin
- produced in the liver when amount of acetyl coa exceeds oxidative capacity of liver
- used by peripheral tissues and cardiac muscle, CANNOT by used by the liver
ketonemia vs ketonuria
ketone bodies build up in blood and in urine
FA degradation vs synthesis
Degradation:
- occurs in the mitochondrial matrix
- multiple enzymes
- NAD, FAD
synthesis:
- occurs in the cytosol of mitochondria
- ACP
- enzyme complex
- NADPH, FADH2
sites of FA synthesis
- liver
- breasts
- adipose tissues
citrate vs carnitine shuttle
Citrate shuttle = OAA and acetyl-CoA combined to form citrate. The citrate shuttle can then allow citrate to get OUT of the mitochondria and into the cytoplasm for fatty acid synthesis. Basically what happens after this is citrate will be cut back into Acetyl-CoA and OAA. Acetyl-CoA can then be used for synthesis of fatty acids.
Carnitine shuttle = Allow FAs to get INTO the mitochondria for fatty acid oxidation by tacking part of the FA to a molecule of carnitine, forming acyl-carnitine. The enzyme responsible for this is CPT1. The acyl-carnitine molecule then goes through a a CACT channel into the matrix and gets converted back into Fatty-acyl-CoA by CPT2. Fatty acid oxidaton then occurs.
ACP define
Acyl carrier protein
this is the protein that guides the intermediates of FA synthesis
enzyme thioesterase define
the thing that cleaves off FA when it is done with synthesis and release it as free molecule
cholesterol
building blocks of steroid hormones
precursors of vitamin D, bile acids, etc.
synthesized in the liver and obtained through eating.
comes from acetyl CoA
HMG -COa reducatse
enzyme that is essential in acetyl coa –> cholesterol synthesis
eicosanoids
derived from eicosanoid acids that are synthesized throughout the body
derived from omega 3/6
control over inflammation and immunity in the body
Ex) arachnoid acid, prostaglandins, thromboxane, leukotriene
sources od NADPH
PP pathway
Citrate shuttle
