L14: Fatty Acid and TG Metabolism Flashcards
Composition of fatty acids?
Hydrophobic tail
Hydrophilic head
Glycerol + 3 fatty acids = ?
Triacylglycerol
____ is the storage and transport form of amino acids
Triacylglycerol
What bonds connect fatty acids to glycerol?
Ester bonds
(acid + OH)
Which type of tissue stores triacylglycerol?
Adipose
Saturated fatty acids lack a ___ in their tail while unsaturated have one
kink
Example of saturated fatty acid? unsaturated?
saturated = butter
unsaturated = olive oil
True or False: Saturated fatty acids are usually a liquid at room temperature whereas unsaturated fatty acids are usually solids at room temperature
False
saturated FA = solid
unsaturated FA = liquid
Omega refers to location of ___ double bond, starting from end of FA tail
first
What are the two essential fatty acids (cannot be made by diet, but be obtained via diet)
1) alpha-linoleic acid (omega-3-fatty acid)
2) linoleic acid (omega-6-fatty acid)
Essential fatty acids are important for ___ signaling and function of ____
lipid; nervous system
___: artificial creation of an unsaturated fatty acid that is SOLID at room temperature
Trans fat
How does the double bond change in trans fats?
Double bond changed from cis to trans (makes tail more linear, similar to saturated fatty acid)
Fatty acids are made at the ___ level and on a large scale in the ___ and ____
cellular; lactating mammary; liver
When nutrient levels are high, intermediates will be transported ___ of the mitochondria and used to create ____ ____
out; fatty acids
True or False: CoA can pass through the inner mitochondrial matrix
False - it cannot
What are the types of CoA pools that exist?
1) Mitochondrial CoA pool
- cannot cross inner mitochondria membrane
2) Cytosolic CoA pool
- cannot EXIT mitpcondrial matrix
Attaching CoA to a molecule will __ molecule from crossing inner mitochondrial membrane
prevent
_____ is an enzyme involved in the first step of fatty acid synthesis.
What happens when it is inhibited?
Isocitrate dehydrogenase
- Citrate accumulation
In the first step of fatty acid synthesis, high levels of ATP lead to?
Transport of citrate from mitochondrial to cytosol
How does high ATP affect Isocitrate dehydrogenase in step 1 of fatty acid synthesis?
High ATP inhibits isocitrate dehydrogenase
In the first stage of fatty acid synthesis, high levels of ATP leads to inhibition of ____, which leads to build up of ___ in the mitochondria and, eventually, its exported into the ___, where it continues to accumulate
isocitrate dehydrogenase;
citrate; cytosol
Why is citrate able to leave the mitochondria in step 1 of fatty acid synthesis?
It is not bound to CoA
Step 2 of fatty acid synthesis occurs in the ___.
Here, citrate is cleaved by which enzyme to reproduce oxaloacetate and acetyl CoA?
cytosl
ATP Citrate Lyase
How does ATP Citrate Lyase add back CoA to the citrate molecule in step 2 of fatty acid synthesis?
Takes CoA from cytosolic pool
In stage 3 of fatty acid synthesis, acetyl CoA is converted to ___ via which enzyme?
malonyl CoA
Acetyl-CoA-Carboxylase
- requires ATP and CO2
What is the rate limiting, irreversible step of fatty acid synthesis?
Stage 3: Acetyl CoA to Malonyl CoA in the cytosol
(Acetyl-CoA-Carboxylase)
Describe stage 4 of fatty acid synthesis?
Production of palmitate from malonyl-CoA
-Using malonyl CoA, Fatty Acid Synthase will take two of its carbons and incorporate them into growing fatty acid chain (1 C lost via CO2)
Each malonyl-CoA unit incorporated increases fatty acids by _ carbons until _ carbons are reacher
2 carbons; 16 carbons (palmitate)
___: the base fatty acid produced, can be modified into numerous other fatty acids; is saturated
Palmitate
True or False: Palmitate is the end product of fatty acid synthesis
True
True or False: fatty acid synthesis is a energy consuming process
True
Polymerization of which enzyme allows for its activation?
ACC
Acetyl-CoA-Carboxylase
What is the positive allosteric regulator for ACC?
Citrate
Rising ____ inhibits polymerization of ACC subunits
palmitate (negative feedback)
