Lipids Flashcards
Are lipids hydrophilic or hydrophobic?
What property does this lead to?
Hydrophobic
Insoluble in water
What are the three types of lipids used as fuel molecules?
Fatty acids
Triacylglycerols
Ketone bodies
What are the three classes of lipids?
Fatty acid derivatives
Hydroxy-methyl-glutaric acid derivatives
Vitamins
What class of lipids are fatty acids, triacylglycerols and ketone bodies a part of?
Fatty acid and triacylglycerols - fatty acid derivatives
Ketone bodies - hydroxy-methyl-glutaric acid derivatives
Key point about ketone bodies
Water soluble
Where are triacylglycerols stored?
So when are they utilised? (3)
Adipose tissue
In prolonged exercise, starvation and pregnancy
Are triacylglycerols hydrophobic or hydrophilic?
So how are they stored?
Hydrophobic
Anhydrous form
What stage of catabolism are triacylglyerols metabolised?
Where?
Stage 1
Extracellular in the GI tract
What are fatty acids stored as?
Where are they stored?
Where are they converted into this?
Triglyceride
Adipose tissue
GI tract
What are fatty acids packaged into? (2)
Where are they then released?
Lipoproteins
Chylomicrons (lipoproteins and lipids compacted together)
Circulation via lymphatics
What are triglycerides released as when required?
What complex are they transported to the tissue as?
Fatty acids
Albumin-fatty acid complex
What are fatty acids activated by during their catabolism?
Where?
Linking to the CoA
Mitochondria
What is the fatty acid-CoA complex transported by?
Across where?
Carnitine shuttle
Across the inner mitchondrial membrane
What type of reactions do fatty acids go through in their catabolism?
What is removed each sequence?
Oxidative
C2
Why are carnitine shuttles used?
Fatty acid CoA complexes do not readily cross the inner mitochondrial membrane
What controls the rate of fatty acid oxidation?
Why?
Carnitine shuttles
As they are regulated by AMP and insulin
What does beta oxidation generate?
Acetyl CoA
Reducing powers
Compare the energy store of fats compared to carbohydrates
Fats is a higher energy fuel
What reaction is fatty acid and glycerol metabolism?
Beta oxidation
Where does beta oxidation occur?
What does it require?
What is it regulated by?
Mitochondria
O2
AMP and insulin
What are the two key examples of glycerol?
Glycerol phosphate
23bisphosphoglycerate
Where is glycerol phosphate produced? (2)
Adipose tissue and the liver
What is a use of glycerol phosphate?
Triglyceride and phospholipid biosynthesis
Where is 23bisphosphoglycerate produced?
Red blood cells
Function of 23bisphosphoglycerate
Regulator of haemoglobin O2 affinity
Where is glycerol metabolised?
Liver
Where are ketone bodies generated?
In what organelle?
From what?
Liver
Mitochondria
Acetyl CoA
When is the production of ketone bodies high?
When what is in excess?
During fasting
CoA
What is the solubility of ketone bodies?
Acid or base?
Soluble
Acidic
Where are ketone bodies used?
Peripheral tissues (muscle)
What is produced when the insulin:glucagon is high?
As, what is inhibited and activated?
What does this indicate about food intake?
Cholesterol
Lyase and reductase
Fed
What is produced when the insulin:glucagon is low?
As, what is inhibited and activated?
What does this indicate about food intake?
Ketone bodies
Reductase and lyase
Starved
Saturation of fatty acids?
Saturated or unsaturated
Fatty acids are amphipathic, what does this mean?
Contain hydrophilic and hydrophobic groups
Why are some fatty acids essential?
Mammals cannot introduce a double bond beyond C9
