W4 (a) - Macro - Fat Flashcards
Fats (Lipids) are hydrophobic? True or False
True, insoluble in water
Are fats and triglycerides interchangeable?
Yes
What 3 fns do lipids provide?
they serve as structural components of cell membranes, function as energy storehouses, and function as important signalling molecules (help body produce and regulate hormones and help with nerve impulse transmission and maintaining tissue structure)
What are lipid molecules broken down into?
smaller molecules of fatty acids and glycerol
What atoms are lipids made up of?
carbon, hydrogen and oxygen atoms
What are the three main types of fats?
Triglycerides (95%); Phospholipids (2% - water soluble, crucial for building cell membranes); Sterols eg cholesterol. However most of the cholesterol in the body is produced by the body.. Cholesterol is an important component of the cell membrane and is required for the synthesis of sex hormones, vitamin D, and bile salts
What chemical features distinguish fatty acids from each other? (5.1)
The number of carbon chain. 18 is the most common, as are long chain (12-24 carbons) often found in meat, fish and veg oil. Med chain (6-10) and short chain (<6) also occur primarily in dairy products; Number of Double Bonds - saturated fatty acids have all their hydrogen atoms and only contain single bonds between their carbon atoms. Unsaturated fatty acids have 2 hydrogen atoms missing and a double bond between it’s carbon atoms. Apolyunsaturated fatty acid has 2 or more carbon to carbon double bonds and mono only one. Linolenic acids, also poly unsat have 3 (carbon to carbon dbl bonds). Location of their double bonds - proximity to the methyl end of the carbon chain which is described by an omge number. A polyunsaturated fatty acid with its first double bond three carbons away from the methyl end is an omega-3 fatty acid. 6 carbons away, omega 6 fatty acid. Note: Mono unsat tend to have their only dbl bond 9 carbons away from the methyl end and are know as Omega-9 mono unsat fatty acids
What role does bile play in lipid absorption?
Bile acts as an emulsifier. It attracts and holds on to fat while it is simultaneously attracted to and held on to by water. Emulsification increases the surface area of lipids over a thousand-fold, making them more accessible to the digestive enzymes.
Once the stomach contents have been emulsified, fat-breaking enzymes work on the triglycerides and diglycerides to severe fatty acids from their glycerol foundations. As pancreatic lipase enters the small intestine, it breaks down the fats into free fatty acids and monoglycerides.
Bile salts envelop the fatty acids and monoglycerides to form micelles. Micelles have a fatty acid core with a water-soluble exterior. This allows efficient transportation to the intestinal microvillus.
Inside the intestinal cells, the monoglycerides and fatty acids reassemble themselves into triglycerides. Triglycerides, cholesterol, and phospholipids form lipoproteins when joined with a protein carrier, a chylomicron, which now enters the lymphatic system, bypassing the liver, and will soon be released into the bloodstream via the jugular vein in the neck.
Cholesterol absorption is aided by an increase in dietary fat components and is hindered by high fibre content.
How does the degree of unsaturation influence fat and oils in food?
Firmness at room temp most poly unsat veg oils are liquid at room temp, more sat animal fats, solid. Generally the shorter the carbon chain the softer the fat is at room temp eg coconut oil vs butter
How can fat lead to CV disease?
A serious impact of excess fat is the accumulation of too much cholesterol in the arterial wall, which can thicken the walls of arteries and lead to cardiovascular disease
What are trans fatty acids and how do they influence heart disease?
They are partially hydrogenated oils (when hydrogen is added to vegetable oil causing it to become solid at room temp). Helps food shelf life. Influence heart disease by increasing LDL and decreasing HDL
How do phosopholipids differ from triglycerides in structure?
Like triglycerides, phospholipids have a glycerol backbone. But unlike triglycerides, phospholipids only have two fatty acid molecules attached to the glycerol backbone,
Tell me about cholesterol
Foods derived from both plants and animals contain sterols, but only those from animals contain significant amounts of cholesterol—meats, eggs, seafood, poultry, and dairy products. Sterols other than cholesterol are naturally found in plants. Being structur- ally similar to cholesterol, plant sterols interfere with cholesterol absorption. By inhibiting cholesterol absorption, a diet rich in plant sterols lowers blood cho- lesterol levels.
What are the fns of sterols?
Many vitally important body compounds are sterols. Among them are bile acids, the sex hormones (such as testosterone), the adrenal hormones (such as cortisol), and vitamin D, as well as cholesterol itself.
What is acceptable macronutrient dist range (AMDR)?
% of macronutrients conume for healthy diet, carbs 45-65%, proteins 15-25%, fats 20-35%
