quizlet

• Name two groups of lipids

  Triglycerides + Phospholipids
• How are triglycerides formed?


  condensation of one molecule of glycerol and three molecules of fatty acid.

  
• In a condensation _ reaction between 3 fatty acids and a glycerol molecule an ester bond is formed
• 3 fatty acids + a glycerol molecule =


  Triglyceride + 3H₂O
• Condensation reaction to form a tryglyceride (Application)

  
• Hydrolysis of a triglyceride produces...


  3 fatty acids and a glycerol molecule
• Lipids are made of the elements...


  carbon, hydrogen, oxygen
• What determines the differences in the properties of triglycerides?

  Variations in the fatty acids
• What is a saturated fatty acid?


  A fatty acid with a carbon chain that has no C=C double bonds
• What is a mono-unsaturated fatty acid?


  A fatty acid with a carbon chain that has asingle C=C double bond
• What is a polyunsaturated fatty acid?


  A fatty acid with a carbon chain that hasmore than one double carbon bond
• Fats are ______ at room temperature


  Solids (saturated)
• Oils are ______ at room temperature

  liquids (unsaturated)
• Describe the Structure of a phospholipid


  made of1 glycerol,2 fatty acidsand1 phosphate.

  phosphate forms ahydrophillichead.

  fatty acids formhydrophobictails.

  
• state 4 roles of Lipids


  -Source of energy

  -Waterproofing

  -Insulation

  -Protection
• Why are lipids good at waterproofing?


  They areinsoluble in water.
• give an example of lipid waterproofing in plants


  plants have waxy lipid cuticles
• give an example of lipid waterproofing in mammals


  Mammals produce anoily secretion, fromsebaceous glandsin the skin.
• why are lipids good insulators?


  they'reslow conductors
• give an example of how lipids are used as insulators in the body


  they make up the myelin sheath.
• How are lipids used as protection


  Stored around delicate organs (e.g. the kidneys)
• Why are unsaturated triglycerides liquids at room temperature?


  The double C=C bondscause the molecule to bend. Therefore,molecules cannot pack together closely, making them liquid (oils) at room temp.
• what is the main function of triglycerides


  STORAGE MOLECULES (in organisms)
• Why are triglycerides a good energy source?

  
  

  High ratio of energy storing C-H bonds to carbon atoms
• Why are triglycerides good storage molecules?


  -Low mass to energy ratio

  -insoluble in water (Large, non polar molecules) , storage does not causeosmotic movementin cells or affectwater potential
• Why are triglycerides are good source of water?


  High ratio of hydrogen to oxygen atoms-Release waterwhen oxidised

  (e.g. source of water for desert organisms)
• explain why triglycerides are insoluble in water, but soluble in other solvents (3)


  they are hydrophobic because they are non-polar.They can't form hydrogen bonds with water molecules.
• Describe what is meant by " a phospholipid is a polar molecule"


  Hydrophilic'head' (phosphate)interacts/attracted to water, not fat.

  Hydrophobic'tail' orients itselfaway from water, mixesreadilywith fat.

  
• Properties of phospholipids related to structure


  -Polar molecules. Form a bilayer in (aq) environment

  -Hydrophilic phosphate heads hold at the surface of a cell.

  -Phospholipid structure allows them to formGlycolipids
• in an aqueous environment, phospholipid molecules form a _______ within cell surface membranes.


  Bilayer
• What process are glycolipids important in within the cell surface membrane?


  Cell recognition
• How does the polarity of a phospholipid aid its function in cell membranes?


  allows phospholipids to form a hydrophobic barrier between the inside and outside of the cell through their bilayer structure

  
• what kind of reaction happens when a phospholipid molecule reacts with glycerol?


  condensation
• define amphipathic


  having both a hydrophilic region and a hydrophobic region
• How does a phospholipid monolayer act as a surfactant


  reduces the surface tension of water
• what type of molecule can pass through a phospholipid bilayer?

  small, non polar molecules (e.g. oxygen)
• what elements do phospholipids contain

  carbon, hydrgen, oxygen, phosphorus
• phospholipid structure


  2 fatty acid 'tails', glycerol molecule, phosphate group

  
• how do phospholipids contribute to membrane stability

  -They are free to move within bilayer

  -will not move into any position where hydrophobic tails are exposed to water

  -making them fluid and stable
• Explain why triglycerides are not considered to be polymers. (1)


  -not made of monomers/many repeating units (ms)