Lipids (classification, fatty acids, steroids, eicosanoids, vitamin D)

lipid molecules that act like hormones; regulate inflammation, pain, fever, and smooth muscle contraction (think childbirth)

prostaglandins

lipid molecules that promote blood clotting and vasoconstriction (made by platelets)

thromboxanes

lipid molecules that are involved in inflammation and allergic response - ASTHMA (not prostaglandins)

leukotrienes

lipid molecules that are pigments found in plants that give yellow, organge and red colours (some are precursors to Vit A)

carotenoids

group of lipid compounds with Vit E activity; act as antioxidants

tocopherols

lipid molecules that are involved in electron transport and energy production in cells

quinones

two features of all lipids

1. soluble in solvents with low polarity

2. are nonpolar

what type of lipids serve as protective coatings in plants and animals?

waxes

which type of simple lipids are composed of esters of long chain fatty acids and long chain alcohols (not glycerol)?

waxes

two types of simple lipids

triacylglycerols and waxes

what type of simple lipids is composed of esters of fatty acids and glycerol?

triacylglycerols

which type of lipids made up of multiple components, usually fatty acids, an alcohol and additional molecules such as phosphates, sugars or proteins?

complex lipids

four examples of complex/compound lipids

phospholipids, glycolipids, lipoproteins and sphingolipids

two common (but not necessary) features of derived lipids

hydrocarbon rings and a long hydrocarbon side chain

compounds produced from hydrolysis of simple and complex lipids

derived lipids

five examples of derived lipids

cholesterol, steroid hormones, fatty acids, glycerol and fat soluble vitamins

classification of lipids based on structure: what are the three classes of lipid structures?

simple, complex and derived lipids

classification of lipids based on function: what are the five major functions of lipids?

1. energy storage

2. membrane components and surface coverings

3. signalling

4. cofactors

5. pigments

example of lipid cofactors (think vitamins)

DEKA vitamins

if a fatty acid contains double bonds is it saturated or unsaturated?

unsaturated

carbons in fatty acids are numbered from which end?

carboxylic end

how would you name a saturated fatty acid with 18 carbons?

octadecanoate

how would you name an monounsaturated fatty acid with 18 carbons?

octadecenoate

what is the name of the C2 carbon in a fatty acid chain? (the first carbon after the carboxylic group)

alpha

how would you name the C3 carbon in a fatty acid chain? (second carbon after the carboxylic group)

beta

how would you name the last carbon in a fatty acid chain?

omega

how would you name an unsaturated fatty acid with 18 carbons and 2 double bonds?

octadecadienoate

how would you name an unsaturated fatty acid with 18 carbons and 3 double bonds?

octadecatrienoate

Δ⁹ is used to denote a double bond present between which two carbons (counting from carboxylic end)

C9 and C10

Δ¹² is used to denote a double bond present between which two carbons (counting from carboxylic end)

C12 and C13

name of linoelic acid (LA) in delta notation

Δ9,12-octadecadienoic acid

name of linoleic acid (LA) in shorthand notation

18:2-6

name of alpha linolenic acid (ALA) in the delta notation

Δ9,12,15-octadecatrienoic acid

name of alpha linolenic acid (ALA) in the shorthand notation

18:3-3

mammals cannot introduce double bonds beyond which carbon?

C9

is gamma linolenic acid (GLA) with the structure 18:3n-6 an omega 3 or omega 6 fatty acid?

omega 6

is alpha linolenic acid (ALA) with the structure 18:3n-3 an omega 3 or omega 6 fatty acid?

omega 3

name of eicosapentaenoic acid in the shorthand notation

20:5n-3

how would you name a fatty acid with the structure 22:6n-3?

docosahexaenoicacid (DHA)

how would you name a fatty acid with the structure 20:5n-3?

eicosapentaenoic acid (EPA)

is linoleic acid omega 3 or omega 6?

omega 6

is alpha linolenic acid omega 3 or omega 6?

omega 3

example of an omega 6 PUFA synthesised by humans

arachidonic acid

example of omega 3 PUFAs synthesised by humans

docosahexaenoic acid and eicosapentaenoicacid

do omega 6 PUFAs tend to produce pro or anti inflammatory metabolites? (answer with 3 words)

pro inflammatory metabolites

do omega 3 PUFAs tend to produce pro or anti inflammatory metabolites? (answer with 3 words)

anti inflammatory metabolites

are eicosanoids produced from omega 3 or omega 6 fatty acids or both?

both

3 common precursors for eicosanoids

arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid

classnof lipid based signalling molecules which act as local mediators

eicosanoids

unsaturated fatty acids are usually … at room temperature because the … interrupt regular packing of the …

liquid, double bonds, chains

the more unsaturated a fatty acid the lower of higher the melting point?

lower

components of triacylglycerols

glycerol + 3 fatty acids

two types of phospholipids

glycerophospholipids and sphingolipids

components of sphingolipids

sphingosine, 1 fatty acid, phosphate and choline

components of glycerophospholipids

glycerol, 2 fatty acids, phosphate and an alcohol

four examples of alcohols found in glycerophospholipids

choline, ethanolamine, serine and inositol

components of glycosphingolipids

sphingosine, glucose or galactose and 1 fatty acid

do glycerophospholipids usually have a saturated or unsaturated FA on C1 of glycerol?

saturated

do glycerophospholipids usually have a saturated or unsaturated FA on C2 of glycerol?

unsaturated

components of lecithin (phosphatidylcholine)

glycerol, phosphate, 2 fatty acids and choline

although lecithin is sometimes used generically to refer to a wide variety of lipids it is most commonly associated with which molecule?

phosphatidylcholine

as all membrane lipids have both a hydrophobic andhydrophilic part they are said to be …

amphipathic

is cholesterol present in membranes of prokaryotic cells?

no

is cholesterol present in membranes of eukaryotic cells?

yes

is cholesterol present in membranes of chloroplasts?

no

is cholesterol present in membranes of mitochondria?

yes

cholesterol is the precursor to which 5 major classes of steroid hormones?

progesterones, estrogens, androgens, glucocorticoids and mineralocorticoids

what class of steroid hormones regulates metabolism, stress response and suppress the immune system (are anti-inflammatory)?

glucocorticoids

what class of steroid hormones regulates electrolyte, salt and water balance (increase sodium reabsorption and potassium excretion in kidneys)?

mineralocorticoids

cholesterol is the precursor to which three classes of biological compounds

1. steroid hormones

2. bile salts

3. vitamin D

leukotrienes are produced from arachidonate by which enzyme?

lipoxygenase (LOX)

prostaglandin synthase has which two distinct activities?

cyclooxygenase (COX) and peroxigenase (POX)

prostaglandin synthase produces prostaglandin H₂ which is the precursor for… (3 words)

prostacyclin, thromboxanes and other prostaglandins

aspirin inhibits which enzyme

COX (1 and 2)

where are corticosteroids produced

adrenal cortex

prostaglandin H₂ is converted to produce prostacyclin (PGI₂) by which enzyme?

prostacyclin synthase

prostaglandin H₂ is converted to produce thromboxane A₂ (TXA₂) by which enzyme?

thromboxane synthase

prostaglandin H₂ is converted to produce various prostaglandins (PGE₂, PGD₂ and PGF_2a) by which type enzymes? —> these enzymes are for example called PGE synthase

terminal prostaglandin synthases

the COX activity of prostaglandin synthase converts arachidonic acid to which intermediate?

PGG2

the peroxidase activity (POX) of prostaglandin synthase converts PGG₂ into which molecule which acts as a precursor used by terminal synthases?

PGH2

which form of vitamin D is the active form

1,25 hydroxyvitamin D

UVB converts … to … in the skin (vit D synthesis)

7 dehydrocholesterol to cholecalciferol

in the liver … is converted to … ( first activation in vit D synthesis)

cholecalciferol to calcidiol

another names for calcidiol and calcitriol

25 hydroxyvitamin D3 and 1,25 dihydroxyvitamin D3

in the kidneys … is converted to … (second activation in vit D synthesis)

calcidiol to calcitriol

which two types of vitamin D do we get prom diets (D₂ and D₃)

ergocalciferol and cholecalciferol

what is the origin of ergocalciferol (vitamin D₂) that we take in from the diet

fungi/yeast

what is the origin of cholecalciferol (vitamin D₃) that we take in from the diet

animal foods