B1.1.7 Triglycerides and Phospholipids Flashcards

1
Q

Which 3 elements do lipids contain?

A

Carbon

Hydrogen

Oxygen

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2
Q

Which part of a phospholipid is hydrophilic?

A

The phosphate ‘head’

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3
Q

Identify the molecule

A

Polyunsaturated fatty acid

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4
Q

What does hydrophobic mean?

A

water hating

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5
Q

How does the structure of triglycerides relate to their properties?

A
  • High ratio of carbon-hydrogen bonds make them an excellent energy source
  • Low mass to energy ratio- animals don’t have to carry a heavy energy store around.
  • Non-polar molecules are insoluble in water so they do not affect osmosis in cells.
  • High ratio of hydrogen to oxygen atoms so water released when trigylcerides are oxidised. Good for animals in deserts.
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6
Q

Identify the molecule

A

Monounsaturated fatty acid

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7
Q

Identify the molecule

A

Phosphate molecule

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8
Q

What state do monounsaturated and polyunsaturated fats take at room temperature?

A

Liquid - they are oils.

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9
Q

What is mean by a saturated fatty acid?

A

A fatty acid that contains no double bonds between the carbon atoms

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10
Q

Identify the molecule

A

Glycerol

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11
Q

Phospholipids are p___________ molecules

A

polar

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12
Q

What state do saturated lipids take at room temperature?

A

Solid - they are fats

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13
Q

What is meant by a polyunsaturated fatty acid?

A

A fatty acid that contains more than 1 double bond between its carbon atoms.

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14
Q

What does hydrophilic mean?

A

attracted to water

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15
Q

What type of bond forms between glycerol and fatty acid molecules?

A

Ester bond

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16
Q

Identify the molecule

A

Triglyceride

17
Q

Identify the molecule

A

Saturated fatty acid

18
Q

What type of reaction takes place when a fatty acid molecule is removed from a glycerol molecule?

A

Hydrolysis

19
Q

What type of reaction takes place when a glycerol molecule joins with a fatty acid molecule?

A

Condensation reaction

20
Q

Describe how you would carry out an emulsion test for lipids

A

The emulsion test for lipids:

  • Add 2cm3 of food and add to a test tube.
  • Add 5 cm3 of ethanol
  • Shake the tube thoroughly to dissolve any lipid.
  • Add 5cm3 of water and shake gently
  • A cloudy-white colour indicates a positive result.
21
Q

Which part of a phospholipid is hydrophobic?

A

The fatty acid ‘tails’

22
Q

What decides the properties of different fats and oils?

A

Variations in their fatty acid chains

23
Q

List the roles of lipids in living organisms.

A
  • Cell membranes
  • Energy store
  • Waterproofing
  • Heat insulation
  • Electrical insulation
  • Protection of organs e.g. kidneys
24
Q

Why are triglycerides called triglycerides?

A

They contain 1 glycerol molecule (glyceride) and 3 fatty acids (tri)

25
What is meant by a monounsaturated fatty acid?
A fatty acid that contains 1 double bond between 1 pair of its carbon atoms.
26
Describe the structure of a phospholipid
1 glycerol molecule attached to 2 fatty acid molecules and 1 phosphate molecule
27
How does the structure of phospholipids relate to their properties?
* Polar molecules - meaning that they can form a barrier (cell membrane) between water inside and outside a cell. * The phospholipid can form glycolipids by combining with carbohydrates. These are important in cell recognition.
28
Name the 2 main groups of lipid
Triglycerides (fats and oils) Phospholipids
29
What happens when a phospholipid is placed in water?
The hydrophilic head positions itself towards water. The hydrophobic tail positions itself away from water
30
Identify the molecule
Phospholipid
31
List the characteristics shared by all lipids
* They contain: Carbon, Hydrogen and Oxygen * Lower proportion of oxygen to carbon and hydrogen than carbohydrates. * Insoluble in water * Soluble in organic solvents e.g. alcohols
32
name the bond between the glycerol and the fatty acid chains in a lipid molecule
ester
33
How can you tell the difference between a fatty acid that is saturated and how which is not?
saturated FA have no double bonds between carbon atoms
34
what is the difference between a triglyceride and a phospholipid?
in a phospholipid, one FA is replaced with a phosphate
35
name the reaction to breakdown phospholipids to release the phosphate
hydrolysis
36
name the element found in all amino acids but not in triglycerides?
Nitrogen
37
Compare and contrast structure of triglycerides and phospholipids
Both have ester bond both contain glycerol fatty acids on both can be saturated or unsaturated Both contain C, H, O but phospholipids have also P Triglycerides have 3 FA, Phospholipds have 2 FA and 1 phosphate group
38
Compare and contrast the properties of triglycerides and phospholipids
Both insoluble in water Triglycerides are hydrophobic/non polar but phospholipids have hydrophobic and hydrophillic (polar) regions Phospholipids form a micelle bilayer but triglycerides dont