Lipids and Fatty Acids Flashcards

1
Q

What is the only thing lipids are soluble in?

A

Only soluble in non-polar solvents

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2
Q

Are fatty acids, hydrophobic or hydrophilic?

2

A

They are amphiphilic

But the hydrocarbon chain generally makes them act hydrophobic

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3
Q

What are the three main functions of lipids in the body?

A

Energy storage

Cellular signalling

Cellular structural components

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4
Q

Describe the structure of a fatty acid?

A

A carboxylic acid (COOH) joined to a long hydro-carbon chain

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5
Q

What is formed when fatty acids undergo saponification?

A

Soap and glycerol

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6
Q

What are the two classifications of fatty acids?

A

Saturated fats

Unsaturated fats

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7
Q

What is a mono-unsaturated fatty acid?

A

One carbon-carbon double bond is present

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8
Q

What is a poly-unsaturated fatty acid?

A

Two or more carbon-carbon double bonds are present

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9
Q

How can unsaturated fats be subcategorised?

A

By the type of double bond present (cis or trans)

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10
Q

Write a note on trans fatty acids.

4

A

Increase amount of LDL

Reduce amount of HDL

Naturally occurring, higher levels in processed foods

Found in butter, milk, ground beef etc

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11
Q

Write a note on cis fatty acids.

5

A

Increase amount of HDL

Naturally occurring

Hydrogenated during food processing to form a saturated fat

Isomerisation during processing to form a trans fat

Found in olive oil, vegetable oil, avocado etc

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12
Q

How are fatty acids named symbolically?

A

x:y ^(Da, b, c)

x = number of Cs in chain
y = number of double bonds
a, b, c are the position of double bonds counting from C1 at the carboxyl end

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13
Q

What is the x in the symbolic naming of fatty acids?

A

The number of Cs in the chain

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14
Q

What is the y in the symbolic naming of fatty acids?

A

The number of double bonds in the chain

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15
Q

What is the a, b, c in the symbolic naming of fatty acids?

A

The position of double bonds counting from C1 at the carboxyl end

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16
Q

What are the four most common omega acids?

A

Omega-3

Omega-6

Omega-7

Omega-9

17
Q

How are omega acids named?

3

A

Omega means its unsaturated

The number tells you where the double bond is

Count back from the last carbon on the hydrocarbon chain

18
Q

What are triacylglycerides?

2

A

Molecules that contain one glycerol group and three fatty acid chains joined by an ester bond

Very hydrophobic

19
Q

Where does the ester bond of TAGs form?

A

They form at the interface between an OH group on the glycerol and the carboxylic acid of the fatty acid

20
Q

What is a glycerol?

A

A 3 carbon sugar alcohol

21
Q

Give three characteristics of glycerol.

A

Odourless

Colourless

Slight sweet taste

22
Q

Give a use of glycerol.

A

Used as a bulking agent in many products

23
Q

How many fatty acids can a glycerol bind?

A

Three

24
Q

What physical change takes place when an unsaturated fatty acid is hydrogenated?

A

An oil becomes a solid

25
Q

What are waxes?

2

A

Chemically heterogenous group of compounds

Formed by an Ester which combines a long chain fatty acid and a long chain alcohol

26
Q

Write a note on waxes.

4

A

Found in both animals and plants

Prevent water loss and protection from pests in plants

Generate a water proof coating in animals

Used in candles, car waxes, cosmetics etc

27
Q

What are membrane lipids/phosphoglycerides?

2

A

Highly variable between tissues and cells

General structure consists of a glycerol 3-phosphate molecule joined with 2 fatty acids

28
Q

What 2 fatty acids join the glycerol 3-phosphate molecule?

A

A saturated C16 or a saturated C18 fatty acid at C1

An unsaturated C18-20 fatty acid at C2

29
Q

How is a phosphoglyceride named?

A

Based on what is attached at the head group substituent of the phosphate group

Phosphatidyl-X

30
Q

What are the two most common phosphoglycerides?

A

Ethanolamine containing

Choline containing

31
Q

Write a note on phosphatidylethanolamine.

3

A

Found on the inner leaflet of the plasma membrane

Important to heart health

Plays a part in blood clotting

32
Q

Write a note on phosphatidylcholine.

4

A

Found on the outer leaflet of the plasma membrane

Found in nearly every cell of the body

Important in the central nervous system

Commercial use as an emulsifying agent

33
Q

What are plasmalogens?

A

A specific class of phosphoglyceride, which contain an ether linked alkenyl chain at the C1 position

34
Q

Give an example of a plasmalogen.

A

Platelet Activating Factor

PAF

35
Q

What does PAF do?

2

A

Signals for the aggregation of platelets at the site of injury

Has a role in inflammation and in allergic reactions

36
Q

What are sphingolipids?

4

A

Based on a 3 carbon backbone. similar to glycerol

Sphingosine added at the C3 position

Fatty acid bound at C2 position (16,18,22 or 24 carbons - sat or unsat)

Ceramide or ceramide derivative at the C1

37
Q

What is sphingosine?

A

A long chain amino alcohol

38
Q

What are glycosphingolipids?

A

They define your blood type

39
Q

What are the five different types of fatty acids?

A

Triacylglycerols

Waxes

Glycerophopholipids

Sphingolipids

Glycosphingolipids