Lipids (mini-test) Flashcards
Are lipids fats?
no
are fats completely hydrophobic?
yes
90% of lipids in food are ________________
fats/triglycerides
What are the functions of lipids?
-store molecules for energy (9 cal per g in fats, 4 cal per g in protein/carbs, lipids are stored in adipose tissue and is insoluble in water while soluble in organic solvents and lipids, we have endless power to store fat)
-structural components of cellular membranes (phospholipid bilayer)
-hormones and vitamins (cholesterol is an important precursor molecule for the synthesis of vitamin D and the steroid hormones like cortisol and estrogen)
-protective molecules (lipids help prevent damage to organs and keep you from getting wet bc of a waxy texture, and helps us insulate)
T/F: there are good and bad lipids
true
What are the 3 major groups of fatty acids?
1) saturated FA
2) unsaturated FA
3) trans fat
What is a fatty acid?
a carboxylic acid with a long carbon-hydrogen tail, which is either saturated or unsaturated
Which fatty acid group has the highest melting temp?
saturated FA
What does saturated FA mean?
saturated with hydrogens, and theres only single bonds
Are saturated FAs solid or liquid at room temp?
solid
What are the food sources for saturated fat?
-animal fat (lard)
-real butter
Are saturated FAs high or low energy?
high energy compared to unsaturated FAs (this is bc saturated FAs have more hydrogens)
Which fatty acid type naturally has a double bond or multiple double bonds?
cis unsaturated fatty acids
What are unsaturated fatty acids?
-FA with a double bond, or multiple double bonds
-if its a cis configuration then its natural and there is a C=C that is kinked because the hydrogens bonded to the carbons are on the same side
-if its a trans configuration then its unnatural/bad for you, it has double bond but is NOT kinked because the hydrogens are on opposite sides, so a trans unsaturated FAs looks similar to a saturated FA
What is a mono-unsaturated FA (MUFA)? What are its characteristics and where is it found?
-1 double bond in the FA
-liquid at room temp but will become solid in cold temp
-olive oil is a MUFA
What are poly-unsaturated FAs (PUFAs)? What are its characteristics and where is it found?
-FA has more than 1 double bond
-liquid at room temp and in cold
-found in fish oil and veggie oil (veggie is cheaper)
What are the characteristics of trans fat? How is it formed?
-double bond(s) that have no kink bc H on opposite sides
-all trans fat is solid at room temp
-unnatural
-formed from partial hydrogenation (hydrogen gas) which causes the unsaturated fat to transition from a cis form to a trans form
-hydrogenation causes an increase in energy because of an increase in hydrogens, so it will become a solid that is spreadable like margarine
-the increase in hydrogens increases the melting temp because energy is increased
-trans fat increases LDL which ultimately increases heart disease
-trans fat is the most stable FA type, so it has an increased shelf life compared to anything else and prevents rancid
Which fatty acid is 18:2?
linoleate, also called linoleic acid
Is linoleate an omega 3, 6, or 9?
omega 6
Linoleate is rich in which food?
veggie oil
What are the 3 essential fatty acids?
1) linoleate (also called linoleic acid)
2) linolenate (also called linolenic acid)
3) arachidonate (also called arachidonic acid)
Which fatty acid is 18:3?
linolenate (also called linolenic acid)
Is linolenate (also called linolenic acid) an omega 3, 6, or 9?
omega 3
linolenate (also called linolenic acid) is rich in which food?
fish oil
butter/animal fat is rich in which 2 fatty acids?
palmitate and stearate
note: a grass-fed cow would have more stearate, while a grain fed cow would have more palmitate
What is the average number of carbons for FAs?
12-20 (usually even numbers)
Are fatty acids amphipathic?
yes
Which fatty acid is 16:0? What do these numbers mean?
-palmitic acid, also called palmitate
-its a saturated FA (SFA)
-the 16 is the number of carbons and the 0 is the number of double bonds (this is known as the delta system)
Which FA is the most abundant in the body/food?
palmitic acid, also called palmitate (it increases blood cholesterol levels and increases risk of heart disease)
Which FA is 18:0?
stearic acid, also known as stearate (its a saturated FA)
Which FA is 18:1, also known as C18:1, C18:1(9) or 18:1 delta 9? What do these numbers mean?
-oleic acid also known as oleate
-its a mono unsaturated FA
-the carbons and double bond are a part of the delta system, the delta showing which carbon has the double bond (smallest number is the one C on left)
Oleic acid also known as oleate is rich in which foods?
avocado and olive oil
Which FA is C20:4, also known as C20:4 (5, 8, 11, 14), or 20:4 delta 5, 8, 11, 14? What do these numbers mean?
-arachidonic acid, also known as arachidonate
-its a poly-unsaturated fatty acid
-the carbons and double bonds are a part of the delta system BUT because it has multiple double bonds it can be calculated which omega it is, per the omega system
-so in this case you take the total carbons number and subtract it by the last C double bond number, which here it would be 6, so this is an omega 6
arachidonic acid, also known as arachidonate is derived from which other FA?
linoleate (also called linoleic acid)
Which FA is conditionally essential?
arachidonic acid, also known as arachidonate