Lipids Flashcards
What makes something a lipid?
-Insoluble in water (hydrophobic)
-Energy dense
-Structural Diverse
Are some lipids amphipathic? What is an example of one? Why is it important?
-Yes, some have both hydrophilic and hydrophobic parts
-Phospholipids are amphipathic
-Amphipathic is important to digestion
What does it mean when a lipid is energy dense?
-1 gram of fat contains 9.45 kcal while protein and carbohydrate only contain 4.1 kcal/g
-lipids have twice the energy as proteins and carbohydrates
What does it mean by a lipid is structural diverse?
-compared to proteins and carbohydrates, lipids are polymers
What are some functional characteristics of lipids related to digestion?
-Energy dense
-Acids in the solubilizing and absorption of lipid soluble vitamins
-Structural contribution to cells
-Act as messengers
How is a lipid being energy dense relate to nutrition? What are examples of this?
-supplies energy in the diet
-also a storage form of energy in the body
-fatty acids in adipose
-adipose tissue: storage form of fat
How do lipids in the diet aid in vitamin lipid digestion?
-Acids in the solubilizing and absorption of lipid soluble vitamins
How do lipids contribute to the structure of cells? What is an example of something lipid based?
-Phospholipids in membranes
-cortisol and any steroids are lipid base
How do we classify lipids?
-By their diverse structures
What are the 2 varieties of lipid structures?
-glycerol based lipid
-anything else
-basically have a glycerol or not
What are examples of non-glycerol based lipids?
-cholesterol
-fatty acids
-steroids
-prostaglandins
-sphingomyelin/cerebrosides: nervous system lipids
What are examples of glycerol based lipid?
-Triglycerides (triacylglycerols)
-Glycolipids
-Phospholipids
-(lipid and a sugar)
What are the two classifications of glycerol based lipids?
-Simple
-Compound
What is a simple glycerol based lipid?
-triglycerides (glycerol and 3 fatty acids)
What is a compound glycerol based lipid?
-Phospholipids and glycolipids (glycerol and 2 fatty acids)
-Phospholipids: adds a phosphate group and possibly an additional functional group
-Glycolipid: adds a sugar like glucose or galactose
Where are triglycerides found?
-oilseeds like
-soybean
-cotton seed
-sunflower seed
-canola
-peanut
-seeds that can be pressed for oils
What is a glycerol composed of?
-3 carbon molecules and 3 oxygen molecules
What is the storage form of fat in humans and animals?
Triglycerides
Are oils from seeds simple or compound glycerolipids?
Simple
What are examples of compound glycolipid and where are they found?
-Phospholipid: found in cell membrane of animals and plants
-Glycolipid: found in plants, structural lipids of plants
Do phospholipids and glycolipids make up a small or large portion of total mass?
Small
How are fatty acids mostly found?
-fatty acids are most often found esterified meaning attached to something
-Fatty aids rarely found free
What are fatty acids often attached to?
-glycerol backbone like
-a triglyceride
-a phospholipid
-or a glycolipids
What do all triglycerides have?
-a glycerol backbone
Are carbons of glycerol in distinct positions in a triglyceride?
Yes
In a triglyceride how many fatty acids are attached to a glycerol backbone?
-3 fatty acids are attached to glycerol backbone
How do fatty acids vary?
-Chain length
-unsaturation: diverse come from fatty acids
What do fatty acids have?
-an aliphatic chain lacking oxygen and a carboxylic acid group
How does chain length vary in fatty acids?
-from 2 to 20 carbons
-generally even numbers of carbons in plants and animals
What are examples of variations in chain length of fatty acids?
-Two carbon acetic acid C2H4O
-Twenty carbon eicosanoid acid C20H40O2
-In animals even number carbon fatty acids
-Same number of oxygen no matter what 2:1 ratio (H:C)
What does saturation mean?
-saturation is a measure of the number of double bonds in a fatty acid
-no double bonds = saturated fatty acid
-meaning all the bond positions of carbons are occupied by other atoms
What does unsaturated mean?
-have multiple double bonds
-one double bond = monounsaturated fatty acid
-two double bonds = polyunsaturated fatty acids
-unsaturated has double bonds btw carbons
What are some common fatty acids?
-16 carbon palmitic acid (saturated)
-18 carbon stearic acid (saturated)
-18 carbon oleic acid (monounsaturated)
-18 carbon linoleic acid (polyunsaturated)
What do double bonds do to a chain of carbons?
-straightens it out
What does cis mean?
-hydrogen on same side of the chain
What does trans mean?
-hydrogens on opposite side of the chain
What does cis geometry implicate about fatty acid shape?
-cis less interaction btw branches
-more space
Is there a higher or lower melting point of a fatty acid has a longer chain length?
-Higher melting point
Is there a higher or lower melting point of a fatty acid if it is more saturated (less unsaturated)?
-means more single bonds
-so lower melting point
What do polyunsaturated fatty acids tend to be at room temperature?
-liquid (oils)
What do longer chains, saturated fatty acids tend to be at room temperature?
-Solid
Do positions of double bonds vary?
-Yes, along the chain
How does double bond position nomenclature work?
-count from the terminal methyl end of the fatty acid
-omega numbers
What does omega w-6 mean? omega-3?
-a double bond is 6 carbons from the methyl end of the fatty acid
-omega 3: 3 carbons in
What are the two essential fatty acids in the diet?
-Linoleic acid
-Linolenic acid
What is linoleic acid?
-18 carbon w-6
-2 double bonds
-omega 6: first double bond at 12th carbon
What is linolenic acid?
-18 carbon w-3
-18 carbons
-3 double bonds
-omega 3: first double bind at 15th carbon
What geometry are linoleic and linolenic acid in?
Cis
Why are linoleic and linolenic acid essential?
-Animals can only add double bonds to fatty acids at position 9 or less along the carbon chain
Where do essential fatty acids have double bonds?
-btw carbon 9 and the methyl end of the fatty acid
Where are essential fatty acids found?
-in cell membranes as fatty acid constituents of phospholipids
What are essential fatty acids used for?
-metabolism: elongated (add more carbons in units of 2) and further desaturated (add more double bonds than in precursor essential fatty acids)
What can linoleic acid (C18:2) become?
-arachidonic acid (C20:4)
What are essential fatty acids precursor to?
-prostaglandins
-thromboxane
-leukotrienes
-short lived local: blood clotting, luteolysis, and immune function
What can linolenic acid (C18:3) become?
-eicosapentaenoic acid (EPA, C20:5)
-docosahexaenoic acid (DHA, C22:6)
~important for nervous system lipids
What omega can fish make?
-omega 3
-they get through diet
Lipid through ruminant?
- Dietary lipids
- Rumen: site of glycolipid hydrolysis and modification of fatty acid profile
- Acid stomach
- Small intestine
Lipid through non-ruminant?
- Dietary lipid
- Acid stomach
- Small intestine: site of glycolipid hydrolysis
How does the rumen modify lipids?
-Microbial lipolysis of glycolipids and biohydrogenation of unsaturated fatty acids
-Emulsification in the small intestine
What do herbivores like ruminants typically consume?
-low lipid diets compared to non-ruminants
Examples of whole plant (forage) lipids?
-glycolipid
-phospholipid
Example of grain (concentrates) lipids?
-triglycerides
Where are glycolipids found?
-structural lipids in plants (hay)
What happens when a ruminant has to much lipids?
-disrupts their digestive