61114
Description
Flashcards by alexlpeart, updated more than 1 year ago
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Created by alexlpeart
over 11 years ago
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| Question | Answer |
| Describe how adrenaline regulates HSL. | Adrenaline cant get into the cell, so must work through a second messenger. It activates Adenylate cyclase which creates cAMP, which causes inactive PK to become active PKA which then causes phosphorylation of HSL (the active form of HSL) |
| Describe how insulin inhibits the phosphorylation of HSL into its active form. | Insulin activates an enzyme called phosphodiesterase which causes the conversion of cAMP into 5-AMP which, preventing the cAMP activating PK to PKA which activates HSL. |
| How does Ca2+ regulate the action of HSL? | Ca2+ activates PKC, CaMKII and AMPK all of which facilitate the production of PKA which facilitates the phosphorylation of HSL meaning it is active. |
| What molecule does leptin activate within the cell to facilitate HSL action? | JAK/STAT |
| How are fatty acids transported into the mitochondria? | Fatty acids combine with CoA in the presence of acyl-CoA synthase to form acyl CoA(outer mitochondrial membrain). The acyl bit of the molecule is then taken by CTPI and combined with carnitine forming acyl-carnitine which moves to CTPII. That the acyl bit of the molecule is then taken by CTPII and removed from the carnitine and put back onto a CoA forming acyl-CoA again (Matrix). |
| Describe beta oxidation, and what products we get from it. What enzyme is measured in studies looking at the mitochondria? | A long chain Fatty acyl-CoA is broken down 2 carbons at a time to form acetyl-CoA, NAHD and FADH2. We would measure 3-hydroxyacyl-CoA dehydrogenase. |
| What is the difference between acyl-CoA and acetyl-CoA? | Acyl-CoA has many carbons (4-24) while acetyl-CoA only has 2 carbons |
| What do we combine with CoA to make Acyl CoA? | Fatty Acid |
| Fatty acids have a hydrophobic ____ and a hydrophilic ____. | Hydrocarbon tail. Carboxylic acid head |
| What is the difference between saturated and unsaturated fats? | Saturated fats have no double bounds with all carbons having the maximum number of hydrogens attached while unsaturated has a double bond. |
| Describe the structure of Triacylglycerol | It has a glycerol backbone and 3 fatty acids attached. |
| Are fats water soluble? How are they transported in the blood? | No, either within albumin as fatty acids or as lipoproteins. |
| Give the 4 types of lipoproteins. | VLDL, LDL, HDL and chylomicrons |
| Describe the process of getting fat from the gut to the correct place in our body. | Triacylglycerides are taken from the gut to the liver by chylomicrons via the thoracic duct. The liver repackages the TG into HDLs, LDLs or if we have got high amounts of free fatty acids VLDLs. These are then transported round the body. |
| LPL activity is activated by ____. This means that .... | Insulin, resulting in increased fat uptake from blood into adipose tissue. |
| What has to happen before we can release TG? What enzyme does this? Give the most common form of this enzyme. | They need to be broken down into Glycerol and free fatty acids. This is catalysised by lipase enzymes. the most common form of this enzyme is HSL |
| Give 5 molecules that stimulate lypolysis. | Exercise (Ca2+), epinephrine, AMP, Adrenergic spill over, Cortisol, Growth hormone, Leptin. |
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