Lipid Structure and Function CH 5 Flashcards
1
Q
How are lipids characterized
A
insolubility in water and solubility in non polar organic solvents
2
Q
Are lipids soluble in water
A
no lipids are insoluble in water
3
Q
Are lipids soluble in non polar organic solvents
A
yes lipids are soluble in non-polar organic solvents
4
Q
What is the role of lipids in the body
A
structural lipids
signaling lipids
energy storage
5
Q
What is the role of structural lipids
A
form vesicles, liposomes, and membranes
6
Q
What is the role of signaling lipids
A
multiple roles
enzyme cofactors
light absorbing pigments
intracellular messengers
hormones
7
Q
What is the role of energy storage lipids
A
workhorse of energy storage
give the most bang for the metabolic buck by weight
8
Q
What are the four main categories of structural lipids
A
phospholipids
glycerophospholipids
sphingolipids
waxes
9
Q
What are he four main categories of signaling lipids
A
terpenes and terpenoids
steroids
prostaglandins
fat soluble vitamins, A, D, E, K
10
Q
What are the two main categories of energy storage lipids
A
triaclglycerols
free fatty acids and saponification
11
Q
What does it mean to be an amphipathic molecule
A
the molecules has both hydrophobic and hydrophilic regions
12
Q
The heads of the membrane lipids are ___ and the tails of the membrane lipids are _____
A
The heads of the membrane lipids are POLAR and the tails fo the membrane lipids are NON-POLAR fatty acid tails
13
Q
How do the polar heads and non polar fatty acid tails form in an aqueous solution
A
non polar fatty acid tails are hydrophobic so they group together and form and internal core and the polar heads are hydrophilic and are on the outside of the membrane
14
Q
What are the three main membrane lipid structures that can form in aqueous solutions
A
liposome, micelle, and phospholipid bilayer
15
Q
What are the elements that make up a phospholipid
A
polar head group: phosphate and an alcohol
non polar fatty acid tail
phosphodiester bond forms between the polar head and fatty acid tail
one or more fatty acids are attached to the backbone of to form the hydrophobic tail region
16
Q
What is the bond between the polar head group and the fatty acid tail in a phospholipid membrane
A
phosphodiester bond
17
Q
How are phospholipids classified beyond the polar head and fatty acid tails
A
can be further classified by the backbone on which the molecule is built
18
Q
What is glycerol and what is glycerol the backbone for
A
three carbon alcohol
backbone for phophoglycerides or glycerophospholipids
19
Q
What kind of backbone doe sphingolipids have
A
sphingosine backbone
20
Q
Are all sphingolipids phospholipids
A
no not all sphingolipids are phospholipids
21
Q
What do all lipids share in common and they vary by what
A
fatty acid tails composed of long fatty acids that vary by degree of saturation and length
22
Q
What type of bonds do saturated fatty acids have between them
A
will only have single bonds
carbon atom is fully saturated when it is bonded to four other atoms
no pi bonds
stronger van der waals forces therefore they form solids at room temperature
23
Q
What type of fatty acids form butter
A
saturated
24
Q
Do saturated or unsaturated fatty acids have stronger van der waals forces
A
saturated fatty acids have stronger van der waals forces therefore they form solids at room temperature
25
What type of fatty acids form olive oil
unsaturated
26
What type of bonds do unsaturated fatty acids have between them
one or more double bonds
double bonds introduce kinks into the fatty acid chain, this makes it difficult for them to stack and solidify
27
In a phospholipid bilayer what types of fatty acids make up the more fluid regions
unsaturated fatty acids make up the more fluid regions of the phospholipid bilayer
28
Whats different between phospholipids, glcerephospholids and sphingolipids?
variety of fatty acid tails (saturated and unsaturated) and different polar head groups
determine the properties of the surface of the cell membrane
29
all ________ are phospholipids but not all phospholipids are ______
glycerophospholipids
30
What are glycerophospholipids
they are phospholipids that...
have a glycerol backbone
ester bond from the backbone to the two fatty acid tails
phosphodiester linkage to a highly polar hear group
31
What is another name for glycerophospholipids
phosphoglycerides
32
How are glycerophospholipids named
named according to their polar head group
33
What is the name of the glycerophospholipid with a choline head group
phosphatidylcholine
34
What is the name of the glycerophospholipids with a ethanolamine head group
phosphatidylethanolamine
35
What type of polar head to phosphatidylcholine and phosphatidylethanolamine have
choline
| ethanolamine
36
What charge can the polar head group have on glycerophospholipids
can be positively, negatively, or neurally charged
membrane surface properties make them important for cell recognition, signaling, and binding
37
What could differ between the fatty acids within subtypes of glycerophospholipids
they can vary in length and saturation
this can cause a different array of functions
38
Are glycerophospholipid, spingolipisds or phospholipids responsible for the ABO blood type system
sphingolipids
39
What is the ABO blood type system based off of
on cell surface antigens of red blood cells
these cell surface antigens are sphingolipids
40
What is the backbone of sphingolipids
sphingosine or sphingoid
these are DIFFERENT
41
What is a glycolipid
any lipid that is linked to a sugar
42
What are the four major subclasses of sphingolipids and how are they broken into these classes
broken into classes based on their polar head group
ceramide
sphingomyelins
glycosphingolipids
gangliosides
43
What are characteristics of ceramide subclass of sphingolipids
simplest sphingolipid
polar head is a single hydrogen atom
44
Which saturation of fatty acid tails are more fluid, what saturation is less fluid
saturated fatty acid tails are less fluid
| unsaturated fatty acid tails are more fluid
45
Does the polar head group of fatty acid tails make the majority of structural thickness of the phospholipid bilayer
fatty acid tail form most of the structural thickness of the phospholipid bilayer
46
What makes some but not all sphingolipids phospholipids
if they contain a phosphodiester bond and these are specifically called sphingophospholipids
47
What is a phosphodiester bond between in a membrane
the bond between the polar head group and the fatty acid tail in a phospholipid membrane
48
What is a phosphodiester bond between in a membrane
the bond between the polar head group and the fatty acid tail in a phospholipid membrane
49
What is the simplest class of sphingolipids
ceramide
polar head with a single hydrogen atom
50
What is the major class of sphingolipids
sphingomyelins
51
Are sphingomyelins phospholipids
yes sphingomyelins are phospholipids specially called sphingophospholipids
52
What are characteristics of sphingomyelins polar head group, bonds, and function
major class of sphingolipids
are a phospholipid
contain either a phosphatidylcholine or phosphatidylethanolamine head group
they have a phosphodiester bond
head group has no net charge
major component of the myelin sheath
major component of the plasma membranes of cells producing myelin (oligodendrocytes and Schwann cells)
myelin insulates the sheath of axons
53
What subclass of sphingolipids have either a phosphatidylcholine or phosphatidylethanolamine head group with no net charge and is a major component of the myelin sheath
sphingomyelins
its the major class of sphingolipids
54
What subclass of sphingolipids have a head group composed of sugars bonded by a glycosidic linkage and are usually found on the outer surface of the plasma membrane
glycosphingolipids
55
What are characteristics of glycosphingolipids polar head group, bonds, and function
not phospholipids because they do not have a phosphodiester bond
polar head group composed of sugars bonded by glycosidic linkages (linked to sugar moieties instead of phosphate)
found mainly on the outer surface of the plasma membrane and can be further classified into cerebrosides and globosides
usually referred to as neutral glycolipids because they have no net charge at a physiological pH
56
What are the two classes of glycosphingolipids
glycosphingolipids are a type of sphingolipids
can be classified into
cerebrosides and globosides
57
What are the characteristics of cerebrosides
a type of glycosphingolipids that are a type of sphingolipids
have a single sugar connected to a sphingosine
58
What are the characteristics of globosides
a type of glycosphingolipids that are a type of sphingolipids
have two or more sugars connected to a sphingosine
59
Why are glycosphingolipids usually referred to as neutral glycolipids
because they have no net charge at a physiological pH
60
What are the most complex class of sphingolipids
gangliosides
61
What are characteristics of gangliosides, polar head group, bonds, and function
polar head group composed of oligosaccharides with one or more N-acetylneuraminic acid (NANA) (also called sialic acid) molecules at the terminus
polar heads have a negative charge
have no phosphate group, therefore they are not phospholipids
called glycolipids because they have a glycosidic linkage and no phosphate group
play a role in cell interaction, recognition, and signal transduction
62
What subclass of sphingolipids have a polar head group with a net negative charge that is composed of oligosaccharides with one or more sialic acid molecule at the terminus
gangliosides
63
Are sphingomyelins phospholipids
yes because they have a phosphodiester bond
64
Are glycosphingolipids phospholipids
no because they have a glycosidic linkage not a phosphodiester bond
called glycolipids
65
Are gangliosides phospholipids
no because have a glycosidic linkage and they do not have a phosphodiester bond
called glycolipids
66
What is the common name for N-acetylneuraminic acid
sialic acid
67
What are characteristics of waxes
contain long-chain fatty acids esterified to long-chain alcohols
used as protection against evaporation and parasites in plants and animals
68
What type of structural lipids have a long-chain fatty acids that are esterified to long-chain alcohols
waxes
69
How do waxes help protect plants
waxes are secreted as a surface coating
to prevent excessive evaporation and to protect against parasites
70
How do waxes help protect animals
waxes are secreted
to prevent dehydration, as a lubricant, and as a repellant to keep skin and feathers dry
bees secrete waxes to construct a structure
humans have earwax for protection
71
What are terpenes
class of lipids built from isoprene C5H8 moieties and share a common structural pattern with carbon grouped in multiples of five
a type of signaling lipid
odiferous chemicals
metabolic precursors to steroids and other lipid signaling molecules
72
What are terpenoids and what is another name for them
derived from terpenes via oxygenation or backbone rearrangements
also called isoprenoids
have similar odorous characteristics
73
What is a monoterpene
one terpene unit,
it is formed by two isoprene units
C10H16
abundant in both essential oils and turpentine (smell derived from resin)
74
What is isoprene
a five carbon molecule that make up terpenes
75
What produces terpenes
produced mainly by plants and also by some insects
generally strong scented
can be pungent chemicals produced by plants or insects to protective them
can be pleasant chemicals produced by plants and extracted as essential oils from plants
76
What would the pleasant chemical produced by plants extracted as essential oil or the pungent odor produced by plants or insects as a defensive mechanism be classified as
terpenes, which is a lipid that's role is in signaling
77
How are terpenes grouped
according to the number of isoprene units present
78
How many isoprene units compose sesquiterpenes
contain three isoprene units
79
How many isoprene units compose diterpenes
contain four isoprene units
vitamin A is a diterpene from which a visual pigment vital for sight is derived
80
How many isoprene units compose triterpenes
contain six isoprene units
can be converted to cholesterol and various steroids
81
How many isoprene units compose tetraterpenes
contain eight isoprene units
carotenoids like beta-carotene and lutein are tetraterpenes
82
How many isoprene chains can be seen in natural rubber and why type of terpene is this considered
natural rubber has isoprene chains between 1000 and 5000 units long and are called a polyterpene
83
How are terpenoids formed
formed from terpenes that have either undergone oxygenation or rearrangement of the carbon skeleton
they are further modified by the addition of different functional groups
84
What is the role of terpenoids
share similar characteristics with terpenes
biological precursor function and aromatic properties
steroid biosynthesis
contribute to the scent of cinnamon, eucalyptus, camphor, turmeric, and numerous other compounds
85
How are terpenoids named
name according to the number of isoprene units present
86
How many isoprene units would be in diterpenoids
derived from four isoprene units
87
Terpenes and terpenoids are precursor molecules for _____
precursor molecules that produce important products that include steroids, which have widespread effects on biological function and vitamin A which is vital to site
88
What molecules are precursor molecules that produce important products that include steroids, which have widespread effects on biological function and vitamin A which is vital to site
terpenes and terpenoids
signaling lipids
89
What are steroids made from
are metabolic derivatives of terpenes
90
Are steroids similar to phospholipids since they both are considered lipids
they are very different in structure and in function
91
What is the structure of steroids
characterized by having four cycloalkane rings fused together: contain three cyclohexane rings and one cyclopentane ring
they have various oxidation state and functional groups may vary
92
What is the steroid functionality determined by
steroid functionality is determined by the oxidation statues of these rings and the functional groups they carry
93
Is a steroid polar or non-polar
steroids are non-polar
94
What are steroids non-polar
steroids are non-polar because the large number of carbons and hydrogens that steroid are made from
95
What is the difference between steroid and steroid hormones
steroids are defined as a group with a particular chemical structure
steroid hormones are steroids that act as hormones
96
Where are steroid hormones secreted and where do they go
secreted by endocrine glands into the bloodstream and then trail on protein carriers to distant sites where they bind to specific high-affinity receptors and alter gene expression levels and metabolism
97
What types of receptors do steroid hormones bind to and what happens after binding occurs
bind to specific high-affinity receptors and alter gene expression and metabolism
98
What are steroid hormones and what do they affect
potent biological signals that regulate gene expression and metabolism
affect a wide variety of biological systems even at low concentrations
99
What are some important steroid hormones
testosterone, estrogens, cortisol, and aldosterone
100
What type of lipids are testosterone, estrogens, cortisol, and aldosterone
signaling lipids that are classified as steroid hormones
101
What types of organisms use steroids as a signaling molecule
animals and plants
102
What level of concentration do steroid hormones have to be at to work
work at low concentrations
103
What is cholesterol
a steroid
important to membrane fluidity and stability
serves as a precursor to a host of other molecules
104
How is cholesterol important for the phospholipid bilayer
major component of a phospholipid bilayer and is responsible for mediating membrane fluidity
105
Is cholesterol amphipathic
yes it has both hydrophobic and hydrophilic components
interactions of both the hydrophobic tails and hydrophilic heads allow cholesterol to maintain a relatively constant fluidity
106
What happens to the membrane if temperatures increase and cholesterol is there
at high temperatures cholesterol keeps the membrane intact and prevents it from becoming too permeable
107
What happens to the membrane if the temperature is lowered and cholesterol is there
at low temperatures cholesterol keeps the cell membrane from solidifying
108
What is cholesterol a precursor for
steroid hormones
bile acids
vitamin D
109
What is the precursor for steroid hormones, bile acids, and vitamin D
cholesterol
110
What are prostaglandins
autocrine and paracrine signaling molecules that regulate cAMP levels (cyclic adenosine monophosphate)
111
Which part of the body do prostaglandins have a big effect on
smooth muscle contractions, body temperature, sleep-wake cycle, fever, and pain
112
Where are prostaglandins produced in the body
produced by almost all cells in the body
113
What molecules are prostaglandins derived from
20 carbon molecules that are unsaturated carboxylic acids derived from arachidonic acid and contain a 5 carbon ring
114
What does cAMP stand for and what is its role
cyclic adenosine monophosphate and it is an ubiquitous intracellular messenger
115
What does cAMP mediate after being synthesized by prostaglandins
cAMP mediates the actions of many other hormones such as the downstream effect of smooth muscle function, influence of sleep-wake cycle, elevation of body temperature associated with fever and pain
116
The down stream effect of ______ can lead to smooth muscle function, influence of sleep-wake cycle, elevation of body temperature associated with fever and pain
prostaglandins synthesizing cAMP
117
What do non-steroidal anti inflammatory drugs such as NSAID (like aspirin) do to the production of prostaglandins
aspirin can inhibit the enzyme cyclooxyrgenase COX which aids in the production of prostaglandins
118
What is a vitamin
essential nutrient that cannot be adequately synthesized by the body so they have to be consumed in our diet
119
What two categories can vitamins be split into
water soluble and lipid soluble
120
What is an essential nutrient that cannot be adequately synthesized by the body so they must be consumed in the diet
vitamins
121
Where are lipid soluble vitamins stored in the body
can accumulate in stored fat
122
Where are water soluble vitamins stored in the body
are excreted through the urine
123
Which vitamins are lipid soluble
A, D, E, and K
124
What is the role of vitamin A
carotene
is metabolized to retinal for vision and retinoic acid for gene expression in epithelial development
125
What is the role of vitamin D
cholecalciferol
is metabolized to calcitriol in the kidneys and regulates calcium and phosphorus homeostasis in the intestines (by increasing calcium and phosphate absorption)
promotes bone formation
deficiency can lead to rickets
126
What is the role of vitamin E
tocopherols
act as biological antioxidants
their aromatic rings destroy free radicals preventing oxidative damage
127
What is the role of vitamin K
phylloquinone and menaquinones
important for the formation of prothrombin (clotting factor)
performs post translational modifications on a number of proteins creating calcium binding site
128
What vitamin is important for the formation of prothrombin and performs post translational modifications on a number of proteins creating calcium binding site and has both
vitamin K
129
What vitamin acts as biological antioxidants and their aromatic rings destroy free radicals preventing oxidative damage
vitamin E
130
What vitamin is also called phylloquinone and menaquinones
vitamin K
131
What vitamin is also called tocopherols
vitamin E
132
What vitamin is also called cholecalciferol
vitamin D
133
What vitamin is also called carotene
vitamin A
134
What vitamin is metabolized to retinal for vision and retinoic acid for gene expression in epithelial development
vitamin A
135
What vitamin is metabolized to calcitriol in the kidneys and regulates calcium and phosphorus homeostasis in the intestines (by increasing calcium and phosphate absorption) and promotes bone formation
vitamin D
136
A deficiency in _____ can lead to rickets
vitamin D, is metabolized to calcitriol in the kidneys and regulates calcium and phosphorus homeostasis in the intestines (by increasing calcium and phosphate absorption) and promotes bone formation
137
What is the preferred method of storing energy for long term use in the body
triacylglycerols also called triglycerides
138
What are the two major reasons that lipids are the best way to store energy
carbon atoms of fatty acids are more reduced than those of sugars (contain numerous alcohol groups) so the oxidation of triacylglycerols yield twice the amount of energy per gram of carbohydrate, far more energy dense storage compared to polysaccharide
they are hydrophobic and do not draw in water so they do not require hydration for stability, helps decrease their weight
139
Why are lipids beneficial for vertebrates living in colder temperatures
layer of lipid is energy storagee and insulation, it helps to retain body heat so less energy is required to maintain a constant internal temperature
penguins, polar bears
140
What are triacylglycerols and triglycerides composed of
composed of one glycerol attached to three fatty acids by ester bonds
it is rare for all three fatty acids to be the same
they are normally varied
141
What are adipocytes and where are they found
animal cells specifically used for storage of large triacylglycerol deposits
found primarily under the skin, around mammary glands, and in the abdominal cavity in animals
found in seeds as oils in plants
142
What are free fatty acids
fatty acids that are unesterified fatty acids with a free carboxylate group
travel in the bloodstream while bound noncovalently to serum albumin
143
What is saponification
ester hydrolysis of triacylglycerols using a strong base such as sodium or potassium hydroxide
traditionally the base was lye which is the common name for sodium or potassium hydroxide
basic cleavage of the fatty acid, leaving the sodium salt of the fatty acid and glycerol, the fatty acid salt is what is called soap
144
What do soaps form
soaps act as surfactants forming micelles
145
What do micelles dissolve and how
can dissolve a lipid-soluble molecule in its fatty acid core and washes away with water because of its shell of carboxylate head groups
soaps form micelles
146
How do triacylglycerol deposits appear inside of cells
can be seen as oily droplets in the cytosol of cells
147
Where do triacylglycerols travel in the body
travel bidirectionally in the bloodstream between the liver and adipose tissue
148
What are the physical characteristics of triacylglycerols determined by
primarily determined by the saturation or unsaturation of the fatty acid chains that make them up
similar to phospholipids
149
How are soaps produced
fatty acids make up soap and are produced through saponification
150
What is a surfactant
lowers the surface tension at the surface of a liquid
serves as a detergent or emulsifier
151
What is a colloid
if a soap was added to an oil and water mixture combined into a single form because of the soap
152
What is the structure of a micelle
tiny aggregates of soap with the hydrophobic tails turned inward and the hydrophilic heads turned outward
the hydrophobic tails can be dissolved in the solution
shields the hydrophobic lipid tails and allow for overall solvation
153
How do micelles help with vitamins
important in the body for the absorption of fat-soluble vitamins A, D, E, K
154
Why do fatty acids and bile salts secreted by the gallbladder form micelles
to increase surface area available for lipolytic enzymes
155
How do some cleaning agents dissolve both water soluble and water insoluble messes at once
non polar compounds can dissolve the hydrophobic interior of the water soluble micelles therefore both water soluble and water insoluble solutions are cleaned
