5.2 Types of Lipid Molecules Flashcards

1
Q

What are we typically referring to when we use the word ‘fat’?

A

triglycerides

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2
Q

What are triglycerides?

A

The major form of lipid in food and in the body. They consist of three fatty acids attached to a glycerol molecule.

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3
Q

What do fatty acids help to determine?

A

The physical properties and health effects of the triglycerides we consume

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4
Q

What are fatty acids?

A

Organic molecules made up of a chain of carbons linked to hydrogen atoms with an acid group at one end.

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5
Q

What are phospholipids?

A

Types of lipids containing phosphorous. The most common are the phosphoglycerides, which are composed of a glycerol backbone with two fatty acids and a phosphate group attached.

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6
Q

What are sterols?

A

Types of lipids with a structure composed of multiple chemical rings.

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7
Q

Chemical Formula of triglycerides.

A

3 fatty acids + glycerol = triglyceride + 3 Water [H from glycerol and OH from fatty acid combined)

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8
Q

What determines the physical properties of a fatty acid?

A

The length of the carbon chain and the type and location of the bonds between the carbon atoms

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9
Q

How can describe a fatty acid structurally?

A

It is a chain of carbon atoms with an acid group (COOH) on one end and a methyl or omego end (CH3).

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10
Q

Describe saturated fatty acids.

A

Contain no carbon-carbon double bonds, Red meat, butter, cheese, and whole milk.

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11
Q

Describe unsaturated fatty acids.

A

Include monounsaturated and polyunsaturated fatty acids.

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12
Q

Polyunsaturated fatty acids.

A

Contain more than one carbon-carbon double bond.

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13
Q

Monounsaturated fatty acids.

A

Contain one carbon-carbon double bond. Canola, olive oil, and peanut oils, as well as nuts and avocados.

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14
Q

Omega-6-fatty acids

A

The first double bond occurs between the sixth and seventh carbon atoms (from the omega end). Corn oil, safflower oil, soybean oil, and nuts

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15
Q

Omega-3-fatty acids

A

The first double bond occurs between the third and fourth carbon atoms, the fatty acid is an omega-3 fatty acid. Flaxseed, canola oil, and nuts

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16
Q

How many carbons do most fatty acids found in plants and animals, including humans, contain?

A

14 and 22 carbons

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17
Q

How long are short-chain fatty acids?

A

4-7 carbons in length

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18
Q

In what state do short-chain fatty acids remain in colder temperatures?

A

Liquid (like those in milk)

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19
Q

How long are medium-chain fatty acids?

A

8-12 carbons

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20
Q

In what state do medium-chain fatty acids remain in colder temperatures?

A

Solidify in the refrigerator but liquid at room temperature (like cococunt oil)

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21
Q

What is the melting point of coconut oil?

A

25° C

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22
Q

How long are long-chain fatty acids?

A

More than 12 carbons

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23
Q

In what state do longer-chain fatty acids remain at room temperatures?

A

Solid (like beef fat)

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24
Q

What is the melting point of beef fat?

A

50° and 70°C

25
Q

What is saturated fatty acid?

A

A fatty acid in which the carbon atoms are bound to as many hydrogens as possible and which, therefore, contains no carbon-carbon double bonds.

26
Q

What are the most common saturated fatty acids?

A

palmitic acid (16 carbons), steric acid (18 carbons)

27
Q

What are some plant sources of saturated fatty acids?

A

palm oil, palm kernel oil, and coconut oil (known as tropic oils)

28
Q

What is the most common monounsaturated fatty acid in our diet?

A

oleic acid in olive and canola oils, beef

29
Q

What is the most common polyunsaturated fatty acid in our diet?

A

linoleic acid in corn, safflower, and soybean oils

30
Q

What makes a fatty acid more likely to be liquid at room temperature?

A

the more unsaturated bonds it contains

31
Q

What are examples of omega-3-fatty acids?

A

Alpha-linolenic acid, found in vegetable oils, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), found in fish oils

32
Q

What are examples of omega-6-fatty acids?

A

Linoleic acid, found in corn and safflower oils, and arachidonic acid, found in meat and fish

33
Q

What is the major omega-6-fatty acid found in the American diet?

A

Linoleic acid

34
Q

What processes are omega-3 and omega-6 fatty acids in the diet important in?

A

blood pressure regulation, blood clotting, immune function

35
Q

Increasing the intake of omega-3-fatty acids, especially EPA and DHA found in fish, has been associated with what?

A

Reduced deaths from cardiovascular disease

36
Q

What are the omega-3 fatty acids in fish?

A

Mainly EPA and DHA

37
Q

What are the omega-6 fatty acids in plant food?

A

Mainly alpha-linoleic acid

38
Q

What is a trans fatty acid?

A

An unsaturated fatty acid in which the hydrogen atoms are on opposite sides of the double bond.

39
Q

In which type of fatty acid does the orientation of hydrogen atoms around the double bond cause a bend in the carbon chain?

A

cis fatty acid

40
Q

Where is a lot of trans fat derived from?

A

partial hydrogenation of vegetable oils

found in - stick margarine and vegetable shortening

& They are also used to lengthen shelf life in other processed foods such as cookies, crackers, breakfast cereals, and potato chips

41
Q

What is hydrogenation?

A

The process whereby hydrogen atoms are added to the carbon-carbon double bonds of unsaturated fatty acids, making them more saturated.

42
Q

Describe conjugated linoleic acid.

A
43
Q

What are the properties of tryglicerdies?

A

Triglycerides may contain any combination of fatty acids: long, medium, or short chain; saturated or unsaturated; cis or trans.

The types of fatty acids in triglycerides determine their texture, taste, and physical characteristics.

44
Q

What are phospholipids?

A

Phospholipids are lipids attached to a chemical group containing phosphorus called a phosphate group

45
Q

What are phosphoglycerides?

A

A class of phospholipid consisting of a glycerol molecule, two fatty acids, and a phosphate group.

46
Q

What is significant about the fatty acid and phosphate ends of a phosphoglyceride?

A

the fatty acid end is soluble in fat while the phosphate end is water-soluble. Likewise, phosphoglycerides can mix with both water and fat.

47
Q

What are emulsifiers?

A

Substances that allow water and fat to mix by breaking large fat globules into smaller ones.

48
Q

What is an example of emulsifiers?

A

egg yolks, which contain phosphoglycerides, function as an emulsifier in cake batter, where they allow the oil and water to mix

49
Q

What is a lipid bilayer?

A

Two layers of phosphoglyceride molecules oriented so that the fat-soluble fatty acid tails are sandwiched between the water-soluble phosphate-containing heads.

50
Q

How do phosphoglycerides act as emulsifiers in food?

A

they can surround droplets of oil, allowing them to remain suspended in a watery environment

51
Q

What is a lecithin?

A

A phosphoglyceride composed of a glycerol backbone, two fatty acids, a phosphate group, and a molecule of choline.

52
Q

What are some natural sources of lecithin?

A

Eggs and soybeans

53
Q

Where else does the food industry use lecithin?

A

an additive in margarine, salad dressings, chocolate, frozen desserts, and baked goods

54
Q

What are some uses of lecithin in the body?

A

cell membranes, synthesize the neurotransmitter acetylcholine

55
Q

What is cholesterol?

A

A lipid that consists of multiple chemical rings and is made only by animal cells.

56
Q

Where is more than 90% of the cholesterol in our body found?

A

cell membranes

57
Q

What are some uses of cholesterol?

A

It can synthesize Vitamin D in the skin; cholic acid, a component of bile called a bile acid; some hormones such as testosterone and estrogen; and cortisol

58
Q

Is cholesterol an essential nutrient?

A

It is needed in the body but because the liver makes it, it is not essential.

59
Q

What are the beneficial effects of plant sterols?

A

help reduce cholesterol levels in the blood by decreasing cholesterol absorption from the diet and increasing the excretion of bile acids, which are synthesized from cholesterol, in the feces