Lipids Flashcards

1
Q

What are lipids?

A

biological molecules that are generally insoluble in water

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2
Q

What can lipids be divided into?

A

Simple - after hydrolysis a maximum of 2 products are produced
Complex - 3 or more products produced

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3
Q

How are lipids classified?

A

By structure or by function

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4
Q

What are storage lipids?

A

Fats and oils used as stored forms of energy are derivatives of fatty acids

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5
Q

What are fatty acids?

A

Carboxylic acids with hydrocarbon chains (4-36 carbons)

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6
Q

What is a saturated hydrocarbon chain?

A

chain with no double carbon bonds

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7
Q

What does the systematic name of fatty acids include?

A

Specifies the chain length and number of double bonds

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8
Q

What are triglycerols (triacylglycerols)?

A

fatty esters of glycerol - 3 fatty acids with a single glycerol molecule

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9
Q

Are triglycerols hydrophilic or hydrophobic?

A

hydrophobic

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10
Q

What are waxes made out of?

A

Esters of long chain saturated or unsaturated fatty acids with long chain alcohols

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11
Q

Name some general types of membrane lipids

A
Glycerophospholipds: 2 fatty acids esterified to G3P
Galactolipds and sulpholipids
Archaeal tetraether lipids
Sphingolipids
Sterols
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12
Q

List some features of the phospholipid bilayer

A

Very low permeability (except water)
permeable to small molecules
need transport proteins

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13
Q

What are some limitations of the phospholipid bilayer?

A

oversimplified and generalised diagrams

descriptions focus on plasma membrane of mammals

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14
Q

Where are galactolipids found?

A

chloroplast membranes

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15
Q

What do sulpholipids contain?

A

sulphonated glucose instead of galactose

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16
Q

Where are sulpholipids found?

A

In plants, algae and cyanobacteria

inner membranes of chloroplasts

17
Q

What is one of the most common sulpholipids in plants and algae?

A

Sulphoquinvosyl dipalmitoylglycerol (SQDG)

18
Q

What structure synthesises lipids?

A

Mitochondria

19
Q

What do membranes have a high content of?

A

Phospholipids

20
Q

Where is Cardiolipin found?

A

Inner mitochondrial membrane

21
Q

What are sphingolipids made out of?

A

1 molecule of fatty acid and sphingosine instead of glycerol

polar head and 2 non-polar tails

22
Q

What are the 3 sphingolipid subclasses?

A

Shphingomyeline, glycosphingolipids, gangliosides

23
Q

What is the function of flippases and floppases in a phospholipid bilayer?

A

Move specific phospholipids against their conc gradient using ATP

24
Q

What molecules do flippases move across the membrane?

A

Aminophospholipds and phosphatidylethanolamine from outer in inner against conc gradient

25
Q

What molecules do floppases move across the membrane?

A

Phosphatidylcholine, sphingolipid and cholesterol against their conc gradients

26
Q

What is the function of scramblases?

A

Facilitate movement of lipids along their concentration gradients without use of ATP

27
Q

During apoptosis what is the function of aminophospholipids (AP)?

A

Activation of scramblases allows rapid appearance of AP on the outer surface of plasma membrane where it provides “eat me” signal

28
Q

Name the three types of Eicosanoids that produce extracellular signals

A

Prostaglandins, Thromboxanes and Leukotrienes

29
Q

What do prostaglandins produce extracellular signals for?

A

Contraction of smooth muscle, fever and inflammation

30
Q

What do thromboxjnes produce extracellular signals for?

A

Formation of blood clots

31
Q

What do leukotrienes produce extracellular signals for?

A

Contraction of smooth muscle lining in airways to the lungs

32
Q

What are steroid hormones derivatives of?

A

Sterols (include sex hormones and glucocorticoids)

33
Q

What do steroid hormones do?

A

Circulate in the blood stream bound to carrier proteins and trigger changes in gene expression

34
Q

What intracellular signal is released under conditions of stress?

A

Shingomyelinases