Fat Digestion Flashcards
Aliphatic meaning
Open chains of carbon atoms rather than rings
Source of basic lipids
From diet (e.g. meat), as well as our own bodies synthesising it
Energy yield from 1 mol of fat
120 mol ATP - 16kJ/mol
Energy yield from 1 mol glucose
32 mol ATP - 36kJ/mol
How fats are separated out, considering that enzymes exist in an aqueous solution and can’t get into fat?
Emulsification with bile salts, derived from the liver. Allows mixing in water. Fat breaks into micelles.
Enzymes involved in breaking the ester linkages between fatty acids and glycerol
Lipase & colipase. First diacylglycerol is formed, then monoacylglycerol, etc.
Where fat is sent for processing
Muscle, adipose tissue, liver, etc. Fatty acids can’t be used to fuel the brain.
Roles of phospholipids
Biomembrane structure & bio-signalling
Roles of sphingolipids
Biomembrane structure and bio-signalling
Role of cholesterol
Used with bile salts in energy and used as steroid hormones in bio-signalling
Role of triglycerides
Energy
Role of fatty acids
Biomembrane structure, bio-signalling and energy
Where is the alpha carbon on fatty acid chains
In the carboxyl group; it is the carbon attached to the carbon with a double bond to oxygen
Where is the beta carbon on fatty acid chains
The carbon adjacent to the alpha carbon
Amount of double bonds in stearic acid and length of the molecule
No double bonds and 18 carbons in total, including the carboxyl group
To what degree are animal fats saturated
Mainly saturated
To what degree are tropical oils of palm and coconut saturated
Mainly saturated
To what degree are some common vegetable oils saturated, such as olive and canola?
Mainly monounsaturated
To what degree are the majority of vegetable oils saturated? For example, corn oil and sunflower oil
Mainly polyunsaturated, w6 linoleic
What weight of glycogen associates with what weight of water?
1g glycogen with 2g water
What is triacylglycerol converted to in the small intestine? And why?
Fatty acid and monoacylglycerol. Two fatty acids are removed. This is to remove them into micelles. Simultaneous digestion by lipase and colipase, then stabilized by bile salts.
What cells absorb mycelles from digestion of fats by lipase?
Epithelial cells
What is formed in the golgi apparatus of epithelial cells when triacylglycerides combine with proteins?
Chylomicrons
Describe what happens to chylomicrons after leaving epithelial cells
They enter lymph capillaries and get transported away by lacteals.
What happens to fat during excess
Lipogenesis; acetyl-coa to triacylglycerol, stored in adipose tissue. Fatty acyl coa and glycerol-3-phosphate are turned into triacylglycerol
What organ are fatty acids used in
Muscle
Where is glycerol sent to and why
The liver and adipose tissue
Role of LPL (lipoprotein lipase) in chylomicrons
Fatty acids released from triacylglycerides, mainly sent to muscles
