Test 3 Review Flashcards
What is the purpose of fatty acids?
Energy production
Where are fatty acids stored? In what?
Adipose tissue
Adipocytes
What is the structure of a fatty acid?
A large organic acids with a long reduced aliphatic carbon chain and a carboxyl group
What type of fatty acids are solid at room temp?
Saturated fatty acids
What type of fatty acids are liquid at room temp?
Unsaturated fatty acids, usually
What variations of fatty acids exist?
Saturated, monounsaturated, polyunsaturated, trans fat
What are two other names for triacylglycerols?
Triacylglycerides, triglycerides
What are the characteristics of TAGs?
- Hydrophobic
- Low Thermal Conductivity
- Melting point makes them stable
What are TAGs composed of?
Glycerol and fatty acids
Phospholipids have what unique property which makes them suitable for membranes?
Amphipathic
(Hydrophobic and hydrophilic)
Where are phospholipids found?
In cell membranes
2 Acyl groups and a phosphate group attached to a glycerol backbone is known as as:
Phosphatidate
What is Phosphatidate composed of?
2 Acyl groups and a phosphate group attached to a glycerol backbone is known as as:
What is the difference between a phospholipid and phosphatidate?
Phosphatidate is the parent compound of glycerophospholipids, the most common kind of phospholipids.
Where are steroids found?
In membranes
They are amphipathic
What are steroids derived from?
Cholesterol
What do steroids act as?
Hormones
What is a cell membrane?
An amphipathic bilayer
What is the purpose of a membrane?
Separation of aqueous solutions, surrounding cells and organelles
What is found in membranes?
Peripheral and integral proteins
Steroids
Where are TAGs stored?
In adipose tissue
Specifically adipocytes (82%)
What protein grants access to TAGs?
Perilipin
TAG synthesis: Step 1
Enzyme:
Reactant:
Product:
Glycerol-3-Phosphate Dehydrogenase
Dihydroxyacetone Phosphate
Glycerol-3-Phosphate
TAG synthesis: Step 2
Enzyme:
Reactant:
Product:
Acyl-CoA Synthetase
Fatty Acid
Acyl-CoA
TAG synthesis: Step 3
Enzyme:
Reactant:
Product:
Glycerol-3-Phosphate Acyl Transferase
Acyl-Coa + Glycerol-3-Phosphate
Lysophosphatidic Acid
TAG synthesis: Step 4
Enzyme:
Reactant:
Product:
Lysophosphatidic Acid Acyltransferase
Acyl-CoA + Lysophosphatidic Acid
Phosphatidate
Exercise speeds Fatty Acid Oxidation mainly by:
Increasing FFA concentration
Exercise speeds Fatty Acid Oxidation mainly by increasing FFA concentration. How?
- Stimulation of Lipolysis in adipose tissue
- Augmented blood flow to muscle
- Enhanced FAT/CD36 translocation to plasma membrane
- Stimulation of Lipolysis in muscle
- β-oxidation rates are high because products are rapidly consumed
Where do Lipolysis occur?
In the cytosol of adipose and muscle tissue
What are the products of Lipolysis?
Fatty acids and glycerol
In the first step of lipolysis, what is the:
Enzyme:
Purpose:
Reactants:
Products:
Triacylglycerol Lipase (HSL)
Hydrolyzes ester bonds 1 and 3
Triacylglycerol
Monoacylglycerol
In the second step of lipolysis, what is the:
Enzyme:
Purpose:
Reactants:
Products:
Monoacylglycerol lipase
Hydrolyzes the final ester bond
Monoacylglycerol
Fatty Acids
What is the main factor that regulates lipolysis?
Hormones
Exercise stimulates _____ from the _____. This binds to ____ which is a _____ receptor. This leads to a _____
Epinephrine and norepinephrine release
Adrenal Medulla and sympathetic neurons
β-adrenergic receptors
G-protein coupled
Cascade of intracellular signaling events. Activation of adenylyl cyclase increases cAMP, which activates Protein Kinase A (PKA), which activates HSL.
PKA activates which two enzymes related to lipolysis?
Triacylglycerol Lipase (HSL)
Perilipin
When does the rate of lipolysis peak?
5 minutes
How does insulin regulate lipolysis?
Insulin inhibits catecholamine action. This activates phosphodiesterase which deactivates cAMP. Phosphatase is then activated which dephospharylates HSL and Perilipin
What is the fate of products made in lipolysis?
Fatty acids undergo β-oxidation in Cytosol
Glycerol is used in gluconeogenesis mostly
Fatty acids are released from ____ (tissue) into the ____.
Adipose tissue
Bloodstream
Which part of the broken down TAG needs a carrier?
Fatty acids, because they are hydrophobic
Why do fatty acids need to be carried into the bloodstream?
The are huge and hydrophobic
What carries fatty acids into the bloodstream?
Albumin
How are fatty acids brought into the cell?
FAT (CD/36) and FABP
Glycerol typically goes to which organ?
Liver
What purpose does glycerol serve in the liver?
Becomes G3P which can be converted into DHAP by glycerol kinase
Where does β-oxidation occur?
In the mitochondrial matrix
A fatty acid longer than ____ cannot pass which membrane?
14
Inner mitochondrial membrane
What three proteins are needed to help fatty acids enter the matrix? Where are they located?
CAT 1 - Outer Mito. Membrane
Translocase - Inner Mito. Membrane
CAT 2 - Inner Mito. Membrane
(Carnitine Acyl-Transferase)
What are the four reactions of β-oxidation?
- Dehydrogenation (FADH2 made)
- Hydration
- Dehydrogenation (NADH made)
- Splitting
What are the products of each round of β-oxidation?
1 FADH2
1 NADH
1 Acetyl-CoA
1 Fa-CoA
How many rounds of beta oxidation occur? Formula?
As many as necessary
For palmitate with 16 C:
16/2 - 1 = 7 rounds
How is it that Fatty Acids produce more ATP than glucose?
Many more carbons. The products (FADH2, NADH, Acetyl-CoA) enter electron transport chain to generate ATP through oxidative phosphorylation
Where are fatty acids synthesized?
In the Cytosol
What is the starting compound for fatty acid synthesis?
Acetyl-CoA
What is the multi enzyme complex?
Fatty Acid Synthase
What is the reducing agent involved with the multi enzyme complex?
NADPH
What is the first compound to bind to the multi enzyme complex?
Acetyl-CoA
What is the second compound to bind to the multi enzyme complex?
Malonyl-CoA
What compound is lost during fatty acid synthesis?
CO2
How many carbons are added at a time during fatty acid synthesis?
2 carbons at a time
What are two other enzymes involved in fatty acid synthesis?
Elongases - Add carbons after palmitate is formed
Desaturases - Remove saturated fatty acid electrons
When palmitate is oxidized what are the products? How many of each?
Acetyl-CoA (8)
FADH2 (7)
NADH (7)
What are the inputs in fatty acid synthesis?
Acetyl-CoA and Malonyl-CoA
What are essential fatty acids?
Fatty acids that humans cannot synthesize on our own. We must consume them
What is Omega-3 and Omega-6?
Polyunsaturated Fatty Acids
Double bond on 3rd carbon and 6th carbon
Where are ketone bodies formed?
Liver
What are the names of the ketone bodies we know?
Acetoacetate
Hydroxybuterate
What compound initially determines ketone body formation?
Oxaloacetate
When this compound accumulates, ketone bodies are formed:
Acetyl-CoA
Where does ketone body oxidation occur?
Extra-hepatic tissues
How much ATP is formed from ketone bodies during exercise?
7%
What are three factors that determine Fatty Acid presence in the blood?
- Lipolysis in adipose tissue
- Blood flow
- Fatty acid uptake in muscle
How does acetyl-CoA affect the FA gradient between the blood and cell?
Acetyl-CoA controls the gradient by regulating FA synthesis, uptake, oxidation, and storage.
What are the FFA concentrations in the blood during:
Light intensity:
Moderate intensity:
High intensity:
Low
Moderate
Low
TAG synthesis: Step 5
Enzyme:
Reactant:
Product:
Phosphatidate Acid Phosphatase
Phosphatidate
Diacylglycerol
TAG synthesis: Step 6
Enzyme:
Reactant:
Product:
Diacylglycerol Acyltransferase
Acyl-CoA + Diacylglycerol
Triacylglycerol
What compound decrease fatty acid oxidation?
Malonyl-CoA
Step 1 of Fatty Acid Synthesis:
Enzyme:
Reactants:
Products:
Acetyl-CoA Carboxylase
Acetyl-CoA
Malonyl-CoA
Step 2 of Fatty Acid Synthesis:
Enzyme:
Reactants:
Products:
Fatty Acid Synthetase
Malonyl-CoA
Acyl group is elongated by 2 carbons, up to 16
