Biochem m3 &4

• Lipids are a ________ group of compounds that are related more by their physical than by their chemical properties.


  heterogeneous
• True or false. Lipids are lighter than water.


  True
• Lipids are poor conductors of ____ and ________ and therefore serve as excellent insulators for the body, slowing the loss of heat through the skin.

  Heat, electricity
• This are a major source of energy for the body, and they also provide the hydrophobic barrier


  Lipids
• Fats and oils can be hydrolyzed in the presence of an acid, a base, or specific enzymes known as ______


  lipase
• The hydrolysis of fats and oils in the presence of a base is used to make soap and is called ______


  saponification
• biomolecules that are soluble in organic solvents and insoluble in water.

  Lipids
• Hydrolyzable lipids are derived from

  Fatty acid
• Naturally occurring fatty acids have an _____

  number of C atoms.

  even
• Non-polar portion =


  Hydrophobic
• _____ fatty acids have no double bonds

  in their long hydrocarbon chains.

  Saturated
• ______ fatty acids have 1 or more double

  bonds (generally cis) in their long hydrocarbon

  chains.

  Unsaturated
• As the number of double bonds in the fatty acid

  increases, the melting point _______


  decreases
• These are esters formed from a fatty acid and a

  high molecular weight alcohol.

  Waxes
• true or false. Waxes are vey hydrophilic

  False
• waxes are hydrolyzed with _____

  in the presence of acid or base to re-form the

  carboxylic acid and alcohol they came from.

  Water
• ______ are three esters

  formed from glycerol and three molecules of

  fatty acids.

  Triacylglycerols
• How many fatty acids does glycerol have

  3
• _____ triacylglycerols have three identical fatty

  acid side chains.

  simple
• _____ triacylglycerols have two or three different

  fatty acids

  mixed
• ________ triacylglycerols have 1 C=C  bond.


  Monounsaturated
• Polyunsaturated triacylglycerols have ____ C=C

  bonds.

  Many
• Phospholipids are lipids that contain a ___ atom.


  P
• ________ are the main component of most cell membranes

  Phosphoacylglycerols
• What are the two main types of phosphoacylglycerols

  Cephalin and lecithin
• The two fatty acid side chains form two _____

  “tails” that lie parallel to each other

  non polar
• true or false. Sphingomyelins contain a glycerol backbone


  false. Sphingomyelins do not contain a glycerol

  backbone, they have a sphingosine backbone 

  instead.
• True or false. Sphingomyelins do not contain an ester; their single fatty acid is bonded to the backbone by an amide bond.


  True
• Phospholipids, the major component of cell

  membranes, contain a  ____ polar head and

  two _____ nonpolar tails.


  hydrophilic, hydrophobic
• When phospholipids are mixed with water, they assemble in a _____ ____


  Lipid bilayer
• Larger polar molecules need _______ _____

  to cross efficiently.

  facilitated transport
• These are a group of lipids whose carbon

  skeletons contain several fused rings

  Steroids
• It is the most prominent steroid, is 

  synthesized in the liver and found in almost all 

  body tissues.

  Cholesterol
• Cholesterol is _______ in the aqueous medium

  of blood.

  insoluble
• It transport cholesterol from the liver to the tissues

  Low-density lipoproteins
• High-density lipoproteins (HDLs) transport

  cholesterol from

  Tissues back to the liver
• It is called bad cholesterol


  Low-density lipoproteins
• It is called good cholesterol

  High-density lipoproteins
• It is a is a molecule that is synthesized in

  one part of an organism, which then elicits a

  response at a different site.

  Hormonw
• Male sex hormones are

  Androgen