Lipid metabolism

Give 4 functions of lipids in the body

Fat has a much higher _____ _________ than carbohydrates or proteins

When _________ ________ exceeds __________, excess is laid down as fat.

Which tissue uses fat as their preferred energy source?

Triglycerides are ______ fats consisting of a ________ molecule which 3 _______ _______ attached. It is a concentrated store of energy.

What are fatty acids?

_________ fatty acids must be obtained from the diet

Humans cannot create double bonds in fatty acids less than position ___

Name 2 places where fatty acid synthesis can take place?

Where in the cell does fatty acid synthesis take place?

What are 3 substrates needed in fatty acid synthesis?

How is citrate formed?

How is the Acetyl CoA transported from the mitochondria to the cytosol for fatty acid synthesis?

What is its mechanism?

How is this transfer mechanism helpful?

Where else can NADPH be obtained from?

What is the first step in fatty acid synthesis?

Which enzyme catalyses this reaction?

What stimulates and inhibits this reaction?

Which vitamin is required for this reaction?

What must Malonyl-CoA and Acetyl CoA bind to in order to be activated?

Acetyl-ACP and Malonyl-ACP combine in a __________ reaction to give ________-____ (4C), releasing _____.

Acetoacetyl-ACP undergoes a ________ reaction, then a __________ reaction, then another _________ reaction. The product is ________-____ and 2 molecules of _______ are used.

Butyryl-ACP combines with another _______-___ molecule to elongate the chain of fatty acids.

All the enzymes required in the elongation of the fatty acid chains form a complex called _____ _____ ________.

Fatty acid synthase exists as a dimer. What does this mean?

Cholesterol is ________ and virtually ________ in water. It is the precursor of _______, ______ and _____ ______.

How is cholesterol transported in circulation?

Where in the body is cholesterol synthesised?

Where in the cell is cholesterol mostly synthesised?

Synthesis of cholesterol is a complex process with many steps. What is the main regulatory step?

What inhibits that enzyme and thus synthesis of cholesterol?

Therefore why is it difficult to reduce circulating cholesterol levels by diet alone?

What are the 3 key steps in releasing energy from fat stores, and where do they take place?

What happens during mobilisation?

What happens to the glycerol?

What happens to the free fatty acids?

In the liver cytoplasm, free fatty acids are activated by _____ to form ______ ______ ____. This is combined with ________ using the enzyme __ __ __ __, to give _____ _____ ________.

The _____ _____ ________ is transported into the matrix of the mitochondria in the liver by _________. In the matrix, __ __ __ __ enzyme converts ______ ______ _________ back into _____ ______ ___ and _________. This transfer process is only needed for longer chain FA.

Once inside the matrix, _______ ____ undergoes __ __________. This process removes __ carbon units and produces _________ ____ , _____ and _____, by a series of reactions.

What is the fate of the FADH2 and NADH produced from beta oxidation?

If there is carbohydrate metabolism also occuring, the ______ ____ produced will enter the ____ ______. However usually if ______ ________ of ______ _____ is taking place, there is little glucose available, so the _____ _______ is not taking place - _________________ is instead making glucose. This process uses _____________ and so _______ ____ builds up and is instead converted to ________ _______.

What are the 3 ketone bodies?

Acetyl CoA is converted to acetoacetate in 3 stages: 1. Acetyl CoA --> _________ ____
2. ________ ____ --> __ __ __ ____
3. __ __ __ ____ --> Acetoacetate

Acetoacetate can then be reduced to give the other ketone bodies: __ __ _____________ _____ and ________.

What causes the sweet fruity smell of people's breath who have ketosis?

Who may be particularly susceptible to this?

Which tissues use ketone bodies as a source of energy?

Which tissue will use ketone bodies for energy during times of starving?

What are 4 effects of insulin in response to high levels of glucose?

What 2 substances stimulate mobilisation of triglycerides in adipose tissue?