Lecture 13 Lipids/Fats Flashcards
How many essential lipids are there?
2
List the dietary functions of lipids? (There’s 7)
- Concentrated source of energy
- Components of all cell membranes
– Every plant or animal cell membrane has fat in it - Precursor for hormones, bile, Vit D etc.
- Source of essential fatty acids
- Increase absorption of fat soluble vitamins
- Insulates organs and nerves
- Improve diet palatability
Why does fat go to the top?
Because its hydrophobic.
Whats most of our carcass made of?
Water
Why do we have an issue?
We have to figure out how to fix. We must make fat water soluble
What does 1g of dry glycogen bind to?
2g of H20
How much energy does 1g of anhydrous fat store? And what does this explain?
6.75 times more energy thank glycogen.
Explains why fat was evolutionary
advantageous as an energy storage
compared to CHO
What does omega mean?
Its ways we identify fatty acids
Whats the difference between oil and lard?
Melting point
Whats important to know in terms of energy in fat?
twice as much energy in fat as there is proteins and carbohydrates
Why is there so much more energy in fat? And per weight basis it contains more?
Because fat is more reduced. It has more hydrogen so the % of total molecular weight hydrogen makes more of a %
So when you are gonna burn a fuel the fuel that has more hydrogen in it is going to have more energy. Its more reduced, you get more hydrogen through the electrode transport chain. More potential for ATP.
How does a cell generate ATP?
Oxidate Phosphorylation.
Whats the key of the TCA cycle?
Kicks off NAD+ AND NADH
What do fatty acids contain more of compared to carbohydrates?
- Compared to carbohydrates, fatty acids
contain more hydrogen molecules per unit of carbon, thus, they are in a more reduced form
– Hydrogen: 1 positively charged proton and 1 negatively charged electron
Why do carbohydrates contain less energy than lipids?
- Carbohydrates are partially oxidized so they contain less potential energy (H+ and e-) per unit of carbon
Whats the functions of bodyfat?
- Cushions body organs
- Insulates the body
- Source of stored calories in times of
sickness or fast
How much does 1lb of adipose tissue contain in kcalories?
3500 kcalories
Name classification of lipids? (5)
1-Fats and Oils (Triglycerides)
2- Glycolipids
3- Phosphoglycerides
4- Steroids
5- Eicosanoids
Fatty acids can be divided into two groups, what are they?
-Saturated (dosnt contain any double bonds)
-Unsaturated(Contains at least 1 double bond)
Whats the chemistry of lipids?
Carbons must have 4 bonds around them
Can be a double bond
Carbon can attach to O,H or C in fats
Tell me a bit about carbon chains?
-Vary in length
-Vary in saturation
1-Saturated (or) 2- Unsaturated
In saturated carbon chains what are they like?
-Maximum hydrogens, no double bonds
-Typically solid at room temperature
In unsaturated carbon chains what are they like?
-At least one double bond
-Typically liquid at room temperature
-Location and orientation of double bonds (non-conjugated, conjugated: cis, trans)
In short chain fatty acids how many carbons is there and what are these know as?
2-6 Carbons - VFA’s
In medium chain fatty acids how many carbons is there?
8-12 Carbons
In long chain fatty acids how many carbons is there?
14-24 Carbons
As the chain length increases the……
Melting point increases
Fatty acids synthesised by plants and animals have how many carbons?
Has an even number of carbons, mostly long chain, 16-18 carbon fatty acids are most prevalent
What is good to know about fatty acids?
With a few exceptions, natural fatty acids:
-Contain an even number of carbon atoms.
-Have a carboxyl group (-COOH) at one end
-Have a methyl group (CH3) at the other end
Animals oils are typically…
Solid
Veg oils are typically….
Liquid