Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biochem 6200 > Lecture 5 Lipids > Flashcards

Lecture 5 Lipids Flashcards

1
Q

Lipids

A

Small hydrophobic or amphiphilic molecules

Extractable by nonpolar solvents (e.g., chloroform:methanol)

Include fats, waxes, sterols, mono/diglycerides, phospholipids, etc.

Originate from ketoacyl and isoprene groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Fatty Acids

A

Simplest form of lipids, found primarily in plasma

-Esterified to glycerol to form triacylglycerol (triglyceride)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Triglycerides

A

solid storage form of lipids, found primarily in adipose tissue (also mono and di forms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Phospholipids

A

major class of membrane lipids in all cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Sterol-containing

A

(cholesterol) compounds and (glyco)sphingolipids linked with biological membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Lipid functions

A

Energy storage, structural elements of cells and organelles, signal transduction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Energy Storage

A

Triglycerides (fats) degrade to glycerol and free fatty acids in response to hormonal signals
Released into plasma for metabolism primarily in muscle and liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Saponification

A

ex vivo hydrolysis by a strong base (e.g., NaOH)

One of the products, sodium salt of the fatty acid = soap

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Structural elements of cells and organelles

A

Vesicles, liposomes, or membranes (plasma) in aqueous environments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Signal transduction

A

hormone precursors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Fatty acids

A

Carboxylic acids with long aliphatic chain. Usually with an even number of carbons, usually unbranched. Saturated or unsaturated. Numbered from carboxyl end.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Common fatty acids

A

Short, medium, long chain. Essential and non-essential.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Short chain

A

2-4 carbon atoms. n = 4, butyric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Medium chain

A

6-10 carbons atoms, n= 8, caprylic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Long chain

A

between 12 and 26 carbons, n=16 palimitic acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Essential and nonessential

A

Cannot and can be synthed in body. Linoleic and linolenic are two essentials.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Acetyl-CoA

A

Central to carb and fat metabolism.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Monounsaturated

A

Single double bond (cis)

Oleic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Polyunsaturated

A

Two or more double bonds
Not conjugated, separated by methylene groups
Linoleic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Polyunsaturated FAs are classified into two groups:

A

ω-3: first double bond appears three carbons from the terminal methyl group
ω-6: first double bond appears six carbons from the terminal methyl group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Physical properties of fatty acids

A

Physical properties largely determined by the length and degree of unsaturation of the hydrocarbon chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Chain length

A

The longer the fatty acid chain length, the poorer the solubility in water.
Carboxylic acid end is polar, imparting moderate solubility of short-chains (

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Fewer double bonds in fatty acid

A

Lower solubility in water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Melting point decreases with

A

number of double bonds - Cis-double bonds place a kink in the linear structure, interfering with close packing, therefore requiring a lower temperature for freezing (i.e., lower melting point; e.g., oils)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Saturated lipids
Saturated lipids - the most stable arrangement is very close packing of the side chains
26
Most fatty acid double bonds
cis
27
Trans fats
Associated with heart disease. Caused by hydrogenation of unsaturated fatty acids. Raises melting point of oils -solid at RT - margarine.
28
Oils can go bad
oxidations of double bonds can result in cleavage to aldehydes and carboxylic acids Rancidity of oils
29
Fatty acids formed in
Liver and adipose tissues, mammary glands during lactation. Unsaturated fatty acids account for 2/3 of all fatty acids in body. Oleate accounts for 1/2 of total Palmitate (saturated) accounts for about one quarter of total
30
Glycerides
Fatty acids are rarely found floating free in solution- can be complex.
31
Carboxylate
Carboxylates (salt or ester) no longer bear a negative charge Very nonpolar - insoluble in water
32
Triacylglycerides
Advantage - storage fuel instead of polysaccharides. More energy present, more reduced than carbs. nonpolar and not hydrated by water - stored in insoluble fat molecules.
33
Lipases
catalyze hydrolysis of ester bonds to glycerol and fatty acids for fuel or other purposes.
34
Glycerides+sodium hydroxide =
glycerol + fatty acids (soap- salt derivatives)
35
Saponification
Forming soap - fatty acids emulsify oils in dirt – allows for removal of oily dirt with water – detergents; micelles, liposomes
36
Phospholipids
Major component of cell membranes. Polar lipids derived from phosphatidic acid. sn-3 position occupied by phosphate esterified to amino compound - choline, serine, etc.
37
Sphingolipids
Second largest phospholipid class. Backbone is not glycerol, but sphingosine. Fatty acid is joined to sphingosine via an amide linkage rather than an ester linkage with glycerol Contain various head groups, including sugars (glycolipids) Found largely in the outer face of plasma membranes Involved as cell surface recognition sites (e.g., red blood cells)
38
Sphingosine
Long chain amino alcohol.
39
Blood groups
Sphingolipids determine this - terminal sugars on sphingolipid determine blood type. Galactose - B, N-acetylgalactosamine = A, N-acetylgalactosamine + galactose = AB, no NAG or GAL = O.
40
Lipopolysaccharide
LPS. Bacterial endotoxin, core oligosaccharide - Bacterial internalization, initiation of immune resistance
41
Long O-antigen side chains - LPS
Responsible for resistance to human serum, antibiotics, detergents
42
Lipid A: hydrophobic anchor
Interacts with host TLR4 to initiate inflammatory response | Fever, hypotension, Gram-negative sepsis
43
Cerebroside examples
One sugar molecule Galactocerebroside – in neuronal membranes Glucocerebrosides – elsewhere in the body
44
Sulfatides or sulfogalactocerebrosides | examples
Sulfuric acid ester of galactocerebroside | Brain lipids, but present in low levels in liver, lung, kidney, spleen, skeletal muscle and heart
45
Globosides
Ceramide oligosaccharides | Lactosylceramide
46
Gangliosides
Complex glycosphingolipid Cell-cell recognition, hormone receptors
47
Sterols
``` Structural lipids that are present in the membranes of most eukaryotic cells. Plants (phytosterols) Fungi (ergosterol) Animals (cholesterol) Four fused rings Three = six-membered One = five-membered Planar main body Lipid-soluble Diffuse freely from the blood through the cell membrane into the cytoplasm of target cells ```
48
Cholesterol
Only found in animal fat Primarily synthesized (and only degraded) in the liver Phytosterols block cholesterol absorption sites in the human intestine Serves as a component of membranes of cells (increases or moderates membrane fluidity) Precursor to steroid hormones and bile acids Storage and transport –cholesterol esters
49
Steroid Hormones
Oxidized derivatives of sterols Do not have the alkyl chain found in cholesterol Increased polarity compared to cholesterol Move through the blood stream attached to protein carriers Five groups based on binding receptors: Glucocorticoids Mineralocorticoids Androgens Estrogens Progestagens Vitamin D closely related receptors, but it is technically a sterol
50
Terpenes
Simple lipids that lack fatty acid component. Formed by the combination of 2 or more molecules of 2-methyl-1,3-butadiene (isoprene)
51
Monoterpene
2 isoprenes c-10 Flavors and odors Limonene (lemons), citronellal (roses/geraniums), pinene (turpentine), menthol (peppermint)
52
Sesquiterpene
(C-15) – 3 isoprenes
53
Diterpene
(C-20) – 4 isoprenes
54
Triterpenes
2 sesquiterpenes C-30 | Precursors of cholesterol and other steroids
55
Tetraterpenes (C-40)
Not as common as mono, di, and triterpenes Includes carotenoids (beta-carotene (precursor of vitamin A) and lycopene (tomatoes)) Colorful compounds
56
Polyisoprenoids or polyprenols
Consist of numerous isoprene adducts (8 – 22) | Side chains of vitamins K, vitamin E and coenzyme Q
57
Prostaglandins and Eicosanoids
Local hormones Key mediators of inflammation Derivatives of prostanoic acid Prostaglandins (e.g., PGE1)
58
PGE1
Blocks gastric production (gastric protection agents) Vasodilator effects Used to treat infants with congenital heart defects PGF2a – causes constriction of the uterus
59
Leukotrienes
Synthesized in neutrophils, monocytes, macrophages, mast cells and keratinocytes Also found in lung, spleen, brain and heart Responsible for inflammation in asthma and bronchitis and anaphylaxis
60
Lipoproteins
Particles found in plasma that transport lipids including cholesterol Liver repackages cholesterol (and triglycerides) into lipoproteins
61
Lipoprotein classes
``` Chylomicrons: take lipids from small intestine through lymph cells Very low density lipoproteins (VLDL) Intermediate density lipoproteins (IDL) Low density lipoproteins (LDL) High density lipoproteins (HDL) ```
62
Lipid-linked Proteins
Different from lipoproteins - proteins with covalently attached lipids - Peripheral membrane proteins. 3 types: Prenylated proteins, Fatty acylated proteins , Glycosylphosphatidylinositol-linked proteins (GPI-linked proteins).
63
Glycosylphosphatidylinositol-linked proteins (GPI-linked proteins)
Occur in all eukaryotes, but are particularly abundant in parasitic protozoa
64
Fatty acylated proteins
Myristoylated and palmitoylated proteins (C14/C16)
65
Prenylated proteins
Farnesylated and geranylgeranylated proteins (C15/C20 isoprene units)
66
Waxes
Esters of long-chain saturated and unsaturated fatty acids with long-chain alcohols Typically have fairly high melting points Skin glands secrete waxes to protect hair and skin to keep it pliable, lubricated, and waterproof
67
Spermaceti – cetyl palmitate
Wax (from whale oil) –useful for pharmaceuticals (creams, ointments, tableting and granulation)
68
Carnauba wax
Brazilian palm tree – a hard wax used on cars and boats
69
Oils
Melting/boiling points are not usually sharp (most fats/oils are mixtures) - liquid. If shaken with water, oils emulsify. Pure fats and oils are colorless and odorless (color and odor result of contaminants) Butter - bacteria give flavor, carotene gives color
70
Calcium and magnesium soaps
Very poorly water soluble (hard water contains calcium and magnesium salts that insolubilize soaps)
71
Floating soap
contains air
72
Transparent soap
(contains sucrose)
73
Green soap
mixture of sodium and potassium linseed oil
74
Castile
Sodium soap of olive oil
75
Potassium
soft soap- shaving soaps are potassium soaps of coconut and palm oils
76
Sodium
Sodium

Biochem 6200 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions