quizlet

    Cards (41)

    • 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)
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