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1
Q

What are lipids used for?

A

Energy storage
Cell structure (like bilayer)
Signaling molecules, cofactors, and pigments

2
Q

What is an advantage of lipids as a fuel versus sugars energetically?

A

Lipids are hydrocarbons so they have less oxygen

Since oxygen oxidizes carbon and takes away electron density, it lowers the energy of the molecule

Therefore, lipids have more energy than sugars since they have less oxygen

3
Q

What is an additional advantage of lipids a fuel versus sugars?

A

they are insoluble in water so there is no extra water weight

in other words, fat is lighter

4
Q

What is the structure of fatty acids?

A

Carboxylic acid with a hydrocarbon chain

5
Q

Saturated fat

A

no double bonds

6
Q

Unsaturated fat

A

has double bonds

7
Q

What is healthier saturated or unsaturated fat?

A

Unsaturated fats like olive oil

8
Q

What happens as chains get longer in fatty acids?

A

Solubility decreases

longer chains interact with each other through Van Der Waals interactions and can precipitate out of solution

9
Q

What are typical lengths for fatty acids?

A

Even numbered length between 12 and 24 carbons

10
Q

What conformation are double bonds in in fatty acids?

A

cis

11
Q

What happens to fluidity when a molecule is saturated?

A

becomes less fluid because strands can get closer together due to lack of kinks

12
Q

What creates trans-fats?

A

hydrogenation to increase storage life and make more stable at high temperatures

13
Q

Triaclygylcerols

A

3 fatty acids and a glycerol linked together through ester linkages

14
Q

Where do we find Triaclyglycerols?

A

In adipose cells for energy storage

15
Q

Characteristics of Triaclyglycerols

A

very insoluble

can be simple or mixed

16
Q

Lipases

A

enzymes that hydrolyze off fatty acids for export of energy

17
Q

What happens if lipases do not work?

A

Get a build up of the lipid that precedes the enzyme in the pathway

Can lead to cell death and neurogenerative diseases

18
Q

Examples of neurogenerative diseases caused by malfunctioning lipases

A

Tay Sachs

Niemann-Pick

19
Q

What causes Niemann-Pick disease?

A

sphingomyelinase which breaks down sphingomyelin doesn’t work

20
Q

Wax

A

two long hydrocarbon chains linked together through an ester carbonyl group

21
Q

Characteristics of wax

A

high melting point

water repellent

allows for bouyancy in whales since wax is lightweight

22
Q

Phospholipids structure and characteristics

A

amphipathic molecules

two fatty acid chains with a phosphoryl group head

form bilayers

23
Q

What type of molecules have trouble crossing the phospholipid bilayer?

A

hydrophillic/polar molecules

the lipids are hydrophobic and make it hard for polar molecules to cross

24
Q

Liposome

A

spherical-shaped vesicle that is composed of one or more phospholipid bilayers

thought to be the early structure of cells in evolution as water and RNA mixed in the sphere

25
Q

List 5 general membrane lipids

A
Glycerophospholipids (aka phospholipids)
Spingolipids (can be a phospholipid too)
Sterols
Galactolipids/sulfolipids
Tetraether lipids (not ours, these are archaeal)
26
Q

Glycerophospholipids

A

two fatty acids that are attached to glycerol

have a phosphate group attached to the glycerol

27
Q

Do all Glycerophospholipids have two fatty acid chains?

A

No

Some molecules found in the heart only have 1 fatty acid chain

This makes it harder for lipases to cut the phospholipid

28
Q

Examples of Glycerophospholipids with one fatty acid chain

A

Plasmalogen and platelet activating-factor

29
Q

Spingolipids

A

do not use glycerol, but instead have one hydrocarbon chain known as the sphingosine

30
Q

List three types of Spingolipids, which are determined by the group attached to the sphingosine

A

Sphingomyelin
Glycosphingolipid
Gangliosides

31
Q

Sphingomyelin

A

a type of spingolipid that has a phosphate group attached to the sphingosine

is technically a phospholipid

only one fatty acid chain per phosphate

has no net charge on head

32
Q

Glycosphingolipid

A

a type of spingolipid that has a sugar group attached to the sphingosine

usually on outer face of plasma membrane with sugar group

no net charge

sugar group helps contribute to recognition

33
Q

Gangliosides

A

a type of spingolipid that has multiple sugar groups attached

net negative charge from sialic acid

34
Q

What is attached to sugars on gangliosides?

A

sialic acid

can have one or multiple sialic acids attached

35
Q

Sterols

A

structural lipids found in the membranes of most eukaryotes

made from the steriod nucleus

36
Q

Are cholesterols polar?

A

they are amphipathetic with polar -OH group on the steriod nucleus head

37
Q

Describe the steriod nucleus

A

planar and stiff

made from ring structures

38
Q

Do steriods always have a hydrocarbon tail?

A

not always! defining feature is actually the steriod head

39
Q

Taurocholic acid (bile acid)

A

an example of a sterol

emulsifies fats by tearing apart glycerol

makes fats more likely to be broken down by lipases

40
Q

Borrelia burgdorferi

A

bacteria that causes lyme disease

45% of its lipids are cholesterol-glycolipids, but the bacteria itself cannot make cholesterol

Borrelia burgdorferi gets cholesterol from the host that they have infected

41
Q

Examples of signaling lipids

A

Phosphatidylinositol and sphingosine derivatives
Eicosanoids
Steroid hormones
Vitamins A, D, K and E

42
Q

Phosphatidylinositol 4,5 Biphosphate (PIP2)

A

a signaling glycerophsopholipid

has a total of 3 phosphates in its glycerol head structure

43
Q

PIP2 mechanism

A

is processed by phosholipase C which removes the triglycerol head (IP3)

IP3 goes into the endoplasmic reticulum to signal the release of calcium

Diacyl glycerol (DAG) remains in the cell membrane and can also serve as a signal

DAG interacts with protein kinase A which binds calcium and results in the phosphorylation of many molecules

44
Q

What type of signaling are Eicosanoids involved in?

A

paracrine signaling

short distance signaling

45
Q

What are all types of Eicosanoids derived from?

A

Arachidonic acid

46
Q

Prostaglandin

A

a type of eicosanoid that is characterized by a 5 membered ring

Prostaglandin is involved in fever, muscle contracting, blood clotting

47
Q

NSAIDs

A

nonsteriodal anti-inflammatory drug

inhibits COX which synthesizes prostaglandin

this reduced prostaglandin and the effects of inflammation

48
Q

Steriods

A

used in endocrine (long distance) signaling

have ring structure

49
Q

How do steroids signals interact with the cell?

A

they are hydrophobic so they can cross the lipid bilayer and go into the cell

receptor for steroids is often inside the cytoplasm

receptors binds the steroid hormone than go into the nucleus where they act as a transcription factor for gene expression

50
Q

Two uses for Vitamin A

A

is used in retinol form in our eyes

regulates gene expression for tissue growth as retionic acid

51
Q

Are vitamins soluble?

A

No

52
Q

Vitamin A and your eyes

A

B-carotene is cleaved to make two vitamin A molecules which are oxidized to make retinal pigment

when light hits retinal pigment, there is a configurational change from cis to trans which triggers signal to brain

(Retinal pigment can also get transformed into retinoic acid which is used to signal epithelial cells)

53
Q

Vitamin D

A

when UV light hits the skin, we produce vitamin D3

Vitamin D3 gets converted by our kidneys and livers into usable nutrients

People with melanin block UV light which can lead to vitamin D defencies

54
Q

Vitamin E

A

Isoprenoid obtained from our diet

Antioxidant- associated with cell membranes and lipoproteins

Protects unsaturated fatty acids from accidental oxidation

55
Q

Vitamin K

A

Isoprenoid obtained from our diet

Undergoes cycle of oxidation and reduction during formation of Prothrombin

Important for blood clotting

56
Q

Isoprenoid

A

Specific type of carbon group found in vitamin E and K

Other isoprenoids are Warfarin, Ubiquinone, and Plastoquinone

57
Q

What are most lipids polymers of?

A

isoprene

58
Q

What is prostaglandin made from?

A

fatty acids

59
Q

What does platelet activating factor contains?

A

an ether-linked alkyl group

60
Q

What is cardiolipin?

A

a glycerophospholipid

NOT a sphingosine

61
Q

Name some sphingolipids

A

ceramide
cerebrosides
gangliosides

62
Q

What do cerebrosides contain?

A

fatty acids

63
Q

Are sterols commonly found in bacteria membranes?

A

no

64
Q

Tay-Sachs disease is caused due to

A

genetic defect in the metabolism of gangliosides

65
Q

Which vitamin is not fat soluble?

A

vitamin C

66
Q

What is vitamin D derived from?

A

cholesterol

67
Q

What is cortisol derived from?

A

sterols

68
Q

Why do lipids float?

A

lower specific gravities than water

69
Q

What do archael membrane lipids have?

A

alkyl acids

70
Q

An example of a glycerophospholipid that is involved in cell signaling is:

A

phosphatidylinositol

71
Q

What are biological uses of waxes?

A

energy storage
lubrication
water proofing
structure

72
Q

Are triaglycerols found in membranes?

A

no?

73
Q

Why is platelet activating factor so water soluble?

A

it’s ester linked acetic acid at the C-2 of glycerol

74
Q

What type of membrane lipids are commonly found in plants?

A

galactolipids

75
Q

Fatty acids are attached to sphingosine by what type of chemical linkage?

A

amide

76
Q

Bile acids are derived from what?

A

cholesterol

77
Q

Signaling lipids produced by platelets in formation of blood clots

A

thromboxanes

78
Q

Nonsteroidal antiinflammatory drugs (NSAIDs) inhibit the synthesis of which signaling lipids from arachidonic acid?

A

both prostaglandins and thromboxanes

79
Q

Thromboxanes

A

help with blood clotting

a type of cholesterol

80
Q

Is aspirin lipid based?

A

no

81
Q

Glycerophospholipids

A

membrane lipids

two fatty acids are attached through ester linkage to glycerol

glycerol also has a phosphodiester linkage and phosphate

82
Q

glycolipids

A

a sphingolipid that has a simple sugar or complex oligosaccharide at their polar ends

83
Q

ether lipids

A

plasmalogens and platet-activating factors

are linked to glycerol-phosphate through ethers

found in the heart

84
Q

galactolipids

A

predominate in plant cells

a type of membrane lipid

one or galactose residues are connected by a glycosidic linkage

85
Q

sphingolipids are what type of lipid?

A

membrane lipid

86
Q

ceramide

A

the parent of all sphingolipids

a fatty acid attached to the amide of the sphingosine

87
Q

Cerebrosides

A

have a single sugar linked to cermide

88
Q

Globosides

A

glycosphingolipids with two or more sugars

89
Q

What determines blood type?

A

sphingolipids in the membrane

90
Q

In what organelle are phospholipids and sphingolipids degraded?

A

lysosomes

91
Q

What are the 3 types of eicosaniod signaling lipids?

A

prostaglandins
thromboxanes
leukotrienes

92
Q

steriod

A

oxidized derivatives of sterols that are used in endocrine signaling

93
Q

Difference between steriods and sterols?

A

Steriods are a type of sterol used for signaling

Not all sterols are used in signaling. For example, cholesterol is used in the cell membrane for fluidity

94
Q

Prothrombin

A

proteolytic enzyme that splits peptide bonds in the blood to convert fibrinogen to fibrin

95
Q

Do branched chains increase or decrease fluidity?

A

increase fluidity