Week 9 Flashcards
What are the 4 ways fat can be metabolised?
- Digest fat and store it in the adipose
- Digest fat and use the energy (beta oxidation)
- mobilise fat from the adipose and use the energy (beta oxidation and ketone body formation)
- Excess carbohydrates can be transferred into fat and stored (liver; lipogenesis)
What helps to emulsify fat droplets?
Bile salts
Where are triglycerides and phospholipids resynthesized?
In epithelial cells
What are chylomicrons made up of?
- Triglycerides
- Phospholipids
- Cholesterol
- Proteins
What is lipoprotein lipase? (LPL)
an enzyme on the endothelial surface
What stimulates and inhibits the expression of LPL?
The insulin in the adipocytes will stimulate it but insulin will inhibit the secretion of LPL in skeletal muscle
LPL in skeletal muscle is activated by glucagon and epinephrine
How are fatty acids made?
Through the hydrolysis of triglycerides
What is Beta-oxidation?
The cleaving of fatty acids
Where does beta-oxidation occur?
in the outer and inner mitochondrial membrane
How are fatty acids transported?
Attached to a CoA from the Acyl CoA synthase creating Fatty Acyl CoA
As fatty acyl CoA cant pass the mitochondria membrane what is it converted into so It can pass?
It is turned into fatty acylcarnitine by carotene palmitoyl transferase 1
What are the 4 reactions in beta oxidation?
- Oxidation reaction
- Hydration Step
- Oxidation step
- Cleavage of beta alpha bond
What are the 4 enzymes in beta-oxidation?
- Acyl-CoA dehydrogenase
- Enoyl-CoA hydratase
- Beta hydroxyacyl CoA dehydrogenase
- Thiolase
What are the products of beta oxidation?
- Fatty acyl CoA
- Acetyl CoA
How does beta oxidation change when a double bond is present?
The first reaction (the oxidation step) is skipped
What is the equation for the number of acetyl CoA that will be produced?
Number of carbons/2
the 2 is for the number of carbons in acetyl CoA
What is the equation for the number of NADH produced?
of acetyl CoA - 1
What is the equation for the number of FADH produced?
of NADH - how many double bonds
What vitamin is essential for fatty acid breakdown?
Vitamin B12
What is medium chain acyl CoA dehydrogenase deficiency?
An inherited defect in beta oxidation
If diagnosed, how is medium chain acyl CoA dehydrogenase deficiency managed?
By avoiding prolonged fasting
What substrates are required for fatty acid synthesis?
Malonyl CoA and 2 NADPH
What regulates acetyl CoA carboxylase?
- AMPK can act as a regulator
- insulin will stimulate
- glucagon will limit it
When does ketone body synthesis occur?
When the body is out of OAA and Acetyl CoA levels are high
What are the two enzymes for ketosis?
Beta hydrobutyrate dehydrogenase and thiolase
What are the problems of ketosis?
- reduces the use of glucose
- increased acetyl CoA
- Increased blood acidity
- tissues without mitochondria’s cannot use them
