Terminology (Lecture 3) Flashcards
Cholecystokinin (CCK) effect
Causes Gallbladder and Pancreas to contract and release enzymes + bile
Secretin Effect
Causes gastric acid secretion
Mixed Micelles
Amphipathic - hydrophobic inside, hydrophilic outside
Brush Border Membrane
In Enterocytes
Primary site of lipid absorption
In what organelle are broken down lipids resynthesized?
Endoplasmic Reticulum
Chylomicrons are surrounded by
- Phospholipids
- Unsterified Cholesterol
- Apolipoprotein
How do lipids enter the bloodstream?
Chylomicrons exocytized from enterocytes into the lacteals (lymph vessels) and then enter bloodstream
too large to enter bloodstream from any source other than the lymph
What tissues absorb chylomicrons from blood?
Fat and Muscle cells
Glycerol use
—> G3P in the Liver for glycolysis or Gluconeogenesis
Main Fatty Acid Esters
Triacylglycerol
Cholesterol Esters
Phospholipids
Location of unsterified (free) FA’s
Transported in circulation with albumin protein
“Listening to albums feeling free, driving in circles”
Fatty Acid chain lengths
12 to 20
Main Fatty Acid components
Carboxylic acid on one end (monocarboxylic acid)
No Double bonds (saturated)
Double bonds (unsaturated)
Why are unsaturated FA’s liquid at RT?
Contain cis double bonds which lengthen structure and lower bp
How far are double bonds spaced?
If more than one, they are spaced every 3 carbons
20:4 (5,8,11,14)
20 Carbons long
4 double bonds (5–6, 8-9, 11-12, 14-15)
Omega Terminology for Linoleic Acid 18:3 (9,12,15)
18:3w-3
Alpha-Linolenic Acid Derivatives
Omega-3 FA’s
3 parts to name
Essential
Linoleic Acid derivatives
Omega-6 FA’s
Essential
How are excess proteins + carbs stored?
Triacylglycerols
FA Synthesis locations
- Mostly liver
- Lactating mammary glands
- Adipose tissue
FA Synthesis Step 1
Acetyl-CoA converted into citrate, transported to cytosol and reconverted
FA Synthesis step 2
A) Acetyl-CoA —> Acetyl-ACP
B) Acetyl-CoA —> Malonyl-CoA
FA Synthesis Step 3
A) Acetyl-ACP —> Acetyl-Synthase
B) Malonyl-CoA —> Malonyl-ACP
FA Step 4
Acetyl-Synthase and Malonyl-ACP combine, undergoing energy consuming reactions to form Palmitate
uses Fatty Acid Synthase (FAS)
FA Synthesis Cont.
End product Palmitate can be added to, 2 carbons at once in the smooth ER
Uses NADPH
Desaturation of FA’s
In the Smooth ER
Cis double bonds inserted by Desaturases
Can only introduce between carbons 9 and 10 (no further)
Storage of FA’s
(1-3) FA’s esterified to a molecule of glycerol… = Monoglycerol, Diglycerol, and Triglycerol
- Usually Saturated
- Usually Unsaturated
- Either
Form anhydrous droplets in adipocytes
Cystolic Lipid Droplets (made of TAG’s)
Major energy reserve of the body
Activation of FA’s
Fatty acyl-CoA synthetases (thiokinases) attach CoA to activate
Alternate storage of FA’s
Little TAG’s stored in liver and exported as VLDL
Beta Oxidation
2-C fragments removed from carboxyl end of activated FA’s
Produces acetyl CoA, NADH, and FADH2
Beta Oxidation Location
Mitochondria
Carnitine Shuttle
How Long Chain Fatty Acids (LCFA’s) get to mitochondria for Beta Oxidation
Even FA beta oxidation end products
Fatty acyl CoA and Acetyl CoA
NADH and FADH2
Odd FA Beta Oxidation
Final 3-C molecule Propionyl CoA metabolized to Succinyl CoA —> Krebs Cycle
Acetyl-CoA from Beta-Oxidation
Converted by liver mitochondria into Ketone bodies
Ketone bodies
Acetoacetate, 3-hydroxybutyrate, and acetone
Ketoacidosis symptom
Fruity breath from acetone
Sphingomyelin
Only major Sphingophospholipid in humans
Myelin nerve fibers
Major structural component in membranes
Phospholipid Synthesis Location
Occurs in Smooth ER
Then transported to Golgi, organelle membranes, plasma membranes, or exocytized
Most Abundant Phospholipids
Phosphatidylethanolamine and phosphatidylcholine
Glycolipids
Carb and lipid components
Derived from ceramides
Essential membrane component and nerve tissue component
Carbohydrate portion is ANTIGENIC
Cerebrosides
Neutral Glycosphingolipids
Ceramide with glucose or galactose
Acidic glycosphingolipids
Negative charge from
NANA acid - gangliosides
Sulfate groups - sulfatides
Glycosyl Transferases + UDP sugar donors
Transfer glycosyl monomers
Make glycosphingolipids in Golgi
Glycosphingolipid production site
Golgi Apparatus
Eicosanoids stem from..
20+C polyunsaturated fats
Collective name for Prostaglandins, Leukotrienes, and Thromboxanes
Eicosanoids
Eicosanoids function
Inflammatory Response
Hypersensitivity to pathogens
Precursor of prostaglandins and thromboxane
Linoleic acid (Omega-6)
Eicosanoids include
- Leukotrienes
- Prostaglandins
- Thromboxanes
Cholesterol functions
- Modulate membrane fluidity
- Precursor of bile acids, steroid hormones, and vitamin D
What organ regulates cholesterol?
Liver
Cholesterol enters the liver as…
- Dietary cholesterol
- Self-made cholesterol
- From extrahepatic tissues
Cholesterol leaves the liver…
- As unmodified cholesterol in bile
- As bile salts secreted into the intestinal lumen
- As VLDL
Sterols
8-10 C steroids
Branched at C17
Cholesterol Synthesis pt. 1
Acetyl-CoA to HMG CoA
Cholesterol Synthesis pt. 2
HMG-CoA to Squalene
Cholesterol Synthesis pt. 3
Squalene to Cholesterol
Ring structure of Cholesterol
Can’t be metabolized to CO2 and H2O
How is cholesterol eliminated?
As bile
Rate limiting step of bile acid synthesis
Cholesterol 7-alpha-hydroxylase
Before bile acids leave the liver
Conjugated to glycine or taurine
Bile contains
- Bile Salts
- Cholesterol
- Phospholipids
- Bile Pigments
Yellow-green Bile
Produced by hepatocytes
Stored in the gall bladder
Chylomicrons
Assembled in intestine
Transport lipids to peripheral tissues
VLDL
Produced in liver
Transports lipids to peripheral tissues
Become LDLs when depleted
LDL
Transport “bad cholesterol” to tissues
HDL
Brings cholesterol from tissues back to liver
“Good cholesterol”
Cholecystokinin
Cause contraction and enzyme release in pancreas + gallbladder
Secretin
Causes enzyme release in pancreas
Lipoprotein Lipase
Breaks down TAGs in bloodstream so they can cross into tissues
Palmitic Acid
16 Carbons (max for fatty acid synthase)
Terminal FA in FA synthesis
