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Biology Paper 1 > Biological Molecules: Lipids > Flashcards

Biological Molecules: Lipids Flashcards

(61 cards)

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1
Q

Name the group represented by COOH:

A

Carboxyl group

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2
Q

What type of R group has a C=C double bond?

A

Unsaturated

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3
Q

What type of R group has a C-C single bond?

A

Saturated

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4
Q

Describe how you would test for the presence of a lipid in a liquid sample of food: (2 marks)

A
  • Add ethanol
  • Then add water and shake
  • A positive result will be a white/milky emulsion
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5
Q

Describe how a triglyceride molecule is formed: (3 marks)

A
  • Formed from one glycerol and three fatty acids
  • Condensation reaction occurs, removing three water molecules
  • Ester bonds form
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6
Q

What is a fatty acid made up of?

A

Hydrocarbon chain attached to a carboxyl group.

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7
Q

What is the general structure of a fatty acid?

A

RCOOH

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8
Q

What is a triglyceride molecule made up of?

A

3 fatty acids
1 glycerol molecule

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9
Q

What are the two types of lipids?

A

Triglycerides
Phospholipid

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10
Q

What is an ester bond?

A

The bond between a glycerol and fatty acid

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11
Q

Why are triglycerides not polymers?

A

Because they are formed of 3 fatty acids and one glycerol molecule, not repeating units of a single monomer.

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12
Q

Name the type of reaction used to break down phospholipids to release phosphate.

A

Hydrolysis

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13
Q

Adding fatty acids into a solution causes the pH of that solution to decrease. Suggest why:

A
  • Fatty acids are acids.
  • A higher concentration of acid in a solution causes the pH to decrease (become more acidic).
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14
Q

What is a monounsaturated fatty acid?

A

An unsaturated fatty acid that only has one double bond between its carbon atoms.

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15
Q

What is a polyunsaturated fatty acid?

A

An unsaturated fatty acid that has more than one double bond between its carbon atoms.

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16
Q

What is the difference between a monounsaturated fatty acid and a polyunsaturated fatty acid?

A

Monounsaturated = Only one double bond between carbon atoms.
Polyunsaturated = More than one double bond between carbon atoms.

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17
Q

Fats, like butter, are made up of ____________ fatty acids.

A

Saturated

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18
Q

Oils, like vegetable oil, are made up of ___________ fatty acids.

A

Unsaturated

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19
Q

Describe the structure of saturated fatty acids:

A

Straight, parallel hydrocarbon chains

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20
Q

Describe the structure of unsaturated fatty acids:

A

Bends in hydrocarbon chains.

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21
Q

Why do triglycerides with saturated fatty acids, like butter, form a solid block at room temperature?

A
  • They have straight, parallel hydrocarbon chains
  • Meaning they don’t take up a lot of space and can be packed tightly together.
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22
Q

Why can’t triglycerides with unsaturated fatty acids, like vegetable oil, form a solid block at room temperature?

A
  • They have bends in their hydrocarbon chains
  • Meaning they take up a lot of space and can’t be packed tightly together
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23
Q

Saturated fats are _______ at room temperature.

A

Solid

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24
Q

Unsaturated fats are _______ at room temperature.

A

Liquid

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25
Butter is a/an __________ fat.
Saturated
26
Vegetable oil is a/an _________ fat.
Unsaturated
27
A fatty acid with no double bonds between carbon atoms is described as _____________.
Saturated
28
A fatty acid with at least one double bond between carbon atoms is described as _____________.
Unsaturated
29
A fatty acid with one double bond is called a __________ fatty acid.
Monounsaturated
30
What are the 3 properties of fatty acids:
- High ratio of hydrogen and carbons to oxygens - Large - Non-polar
31
Why are triglycerides non-polar?
Their non-polar region is much bigger than their polar region
32
What happens when a triglyceride is dropped on water? Why?
- It sits on top of the water - Water is polar, triglyceride is non-polar - Polar molecules and non-polar molecules do not mix - Triglycerides are insoluble in water
33
Why are triglycerides hydrophobic?
- Triglycerides are non-polar, water is polar - Non polar and polar molecules do not mix - Triglycerides are insoluble in water
34
Why are triglycerides a good energy source?
They have a high: carbon and hydrogen: oxygen
35
Explain how storage of fat in the hump of a camel can help it survive in the desert:
- Fat in the hump is stored as triglycerides. - During respiration triglycerides are used to produce ATP, also releasing water. - The high C&H:O means many water molecules can be produced. - Large amounts of energy released will provide energy for camel when food is scarce. - Low mass:energy means lots of energy is stored in a small space.
36
Describe the structure of a phospholipid:
- 2 fatty acid tails - 1 glycerol molecule - 1 phosphate group
37
The fatty acid tails in a phospholipid are attached to the glycerol molecule with _______ bonds.
Ester
38
State 4 similarities between triglycerides and phospholipids:
- Both contain ester bonds - Both contain glycerol - Both have fatty acid tails - Both have hydrogen, oxygen and carbon
39
State 2 differences between triglycerides and phospholipids:
- Phospholipids contain a phosphate group, triglycerides do not. - Phospholipids have two fatty acid tails, triglycerides have three fatty acid tails.
40
Why are triglycerides insoluble in water?
They have a non-polar region (hydrophobic).
41
What are the two functions of phospholipids:
- Make cell surface membranes flexible - Enable cell recognition
42
Explain how phospholipids make cell-surface membranes flexible:
- Phospholipids contain a mix of saturated and unsaturated fatty acids. - Unsaturated fatty acids cant be packed tightly together, so they form gaps in the cell surface membrane. - Allows phospholipids to tilt side-side
43
Explain how phospholipids allow cell recognition:
- Can combine with a carbohydrate to produce glycolipids. - Glycolipids prove to our immune system that it is a self-cell.
44
Name the three structures that phospholipids can form in water:
- Micelle - Monolayer - Bilayer
45
Why are phospholipids insoluble in water?
Hydrophobic tails
46
Why can small molecules like O and CO2 pass through the lipid bilayer without using a transport protein?
Unsaturated fatty acids create gaps in the bilayer which makes the cell surface membrane flexible so small molecules can pass through.
47
Why are triglycerides and phospholipids soluble in alcohol?
- Ethanol has a polar and a non-polar region - So ethanol is able to mix with polar and non-polar substances
48
What are fatty acid tails made up of?
Hydrocarbons
49
What property of triglycerides makes them insoluble in water?
Hydrophobic fatty acid tails
50
What are the two types of fatty acids?
Saturated Unsaturated
51
Saturated fatty acids have a _____ CC bond.
Single
52
Unsaturated fatty acids have a _____ CC bond.
Double
53
What causes unsaturated fatty acids to kink?
Double CC bond.
54
Where are ester bonds formed?
Glycerol molecule Fatty acid
55
Triglycerides are formed through a ______ reaction.
Condensation
56
Where are phospholipids found?
Cell membranes
57
What is the difference in the structure of triglycerides and phospholipids?
Triglycerides : 1 glycerol, 3 fatty acids Phospholipids : 1 glycerol, 2 fatty acids, 1 phosphate group
58
The phosphate group in phospholipids is hydro_____.
Hydrophilic
59
Why are triglycerides good storage molecules?
1) Long hydrocarbon fatty acid tails contain lots of chemical energy = Lots of energy is released when they are broken down 2) Insoluble in water = Wont affect cells water potential
60
The phospholipid heads are hydro____ and their tails are hydro____.
Hydrophilic Hydrophobic
61
The centre of the phospholipid bilayer is ______.
Hydrophobic

Biology Paper 1 (29 decks)

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