lipids Flashcards

1
Q

what do all lipids have in common with respect to solubility

A
  • they all have low solubility in aqueous solutions
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2
Q

what does 20:2 (Δ^8,11) mean when describing a fatty acid?

A
  • there are 20 saturated carbons and 2 unsaturated carbons
  • carbons 8 and 11 are the start of the double bond
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3
Q

how do hydrocarbon chain length and saturation affect the melting point of fatty acids? How do these affect the tightness of packing between fatty acids into aggregates?

A
  1. longer chain and higher saturation = higher melting point, lower solubility
  2. longer chain = tighter packing because more interactions
  3. unsaturated fatty acids have more kinks, which reduces tightness of packing
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4
Q

for unsaturated fatty acids, is the conformation around the double bond usually cis or trans?

A
  • almost always cis
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5
Q

what is the basic structure of a triglyceride

A
  • three fatty acids with ester linkage to a glycerol
  • can have the same or different types of fatty acids
  • can be saturated, unsaturated, or combo
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6
Q

what is more soluble, a fatty acids, or triglyceride? why?

A
  • carboxylic acids are more polar than the OH groups on a glycerol
  • polarity from carboxylic acids lost in ester bonds to the glycerol
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7
Q

what fuel storage lipid is contained in adipocyte cells?

A
  • triacylglycerols
  • form oily droplets int he cytoplasm of eukaryotic cells
  • adipocytes store fat droplets that nearly fill the cell
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8
Q

why are fats better for long-term storage of energy compared to carbohydrates?

A
  • carry more energy because theyre more reduced
  • they are hydrophobic and therefore unhydrated, so the organism doesn’t have to carry water weight to store it
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9
Q

how do sphingolipids and glycerolipids differ?

A
  • sphingolipids have an amide linkage to fatty acid, glycerolipids are ether-linked
  • glycerol backbone vs sphingosine backbone
  • triglycerides are a type of glycerolipids
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10
Q

what are three major parts of the cholesterol molecule?

A
  1. polar head group
  2. steroid nucleus (four connected rings)
  3. alkyl side chain
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11
Q

structurally, how are steroid hormones different from cholesterol?

A
  • ## steroids lack the hydrocarbon chain (more polar)
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