chapter 12 lipids and membranes Flashcards
Lipids are a very diverse set of molecules related how?
By their hydrophobic properties
What are the hydrophobic properties of lipids?
- not appreciably soluble in water
- soluble in organc solvents
- waxy, greasy or oily compounds in plants and animals.
Are lipids soluble in water?
Not appreciably soluble
Are lipids soluble in chloroform (CHCl3)?
yes because its an organic solvent
Are lipids soluble in methanol (CH3OH)?
yes because it is an organic solvent
How is lipid formation different than other biomolecules
Lipids form large aggregates, but not polymers like other biomolecules.
What are function of lipids?
Functions are diverse:
- Storage of energy
- Structure of cell membranes
- Signaling and other biological activities
What are the two main categories of classifying lipids?
1) Saponifiable
2) Non-saponifiable
What are Saponifiable?
Ester-containing compounds
What are non-saponifiable?
Does NOT contain an ester group and are NOT capable of being hydrolyzed
Steroids are an example what type of lipid?
Non-saponifiable thus not able to be hydrolyzed
Eicosanoids are an example of what type of lipids?
Non-saponifiable thus not hydrolyzed
Sphingolipids are an example of what type of lipid?
Saponifiable meaning it contains an ester containing compounds
Glycerophospholipids are an example of what type of lipid?
Saponifiable; meaning it contains an ester containing compounds
Triacylglycerides are an example of what type of lipid?
Saponifiable; meaning it contains ester containing compounds
What are fatty acids?
carboxylic acids with long-chain hydrocarbon side groups
/\/\/\/\/\/\/\/\/\/\/\/\/COOH
is an example of what type of lipid?
fatty acid (non polar tail and polar head)
Is the polar head of a fatty acid soluble? if so under what conditions?
yes at physiological pH (7.4)
If a fatty acid has a polar head of COOH and is in water at physiological pH (7.4) what dominates?
carboxylate ion (COO-) dominates
What are the common characteristics of fatty acids?
- tails are usually straight
- most range from 10-20 carbons
- Usually even # carbons
Are fatty acids saturated, unsaturated or polysaturated?
all of the above
Most unsaturated fatty acids have hat type of configuration?
almost always cis-isomers
Common name: Lauric acid has a systemic name of what?
dodecanoic acid
Dodecanoic acid is also called what?
Lauric acid
What is the structure of Dodecanoic acid (Lauric acid)?
CH3(CH2)10COOH
What is the melting point of Dodecanoic acid (Lauric acid)?
44.2 degrees C
What is the systemic name of Myristic acid?
Tetradecanoic acid
Tetradecanoic acid is also called what?
Myristric acid
What is the structure of Tetradecanoic acid (Myristic acid)?
CH3(CH2)12COOH
What is the melting point of Tetradecanoic acid (Myristic acid)?
53.9 degrees C
What is the systemic name for Palmitic acid?
Hexadecanoic acid
What is the common name for Hexadecanoic acid?
Palmitic acid
What is the structure of Hexadecanoic acid (Palmitic acid)?
CH3(CH2)14COOH
What is the melting point of Hexadecanoic acid (palmitic acid)
63.1 degrees C
What is systemic name for Stearic acid?
Octadecanoic acid
What is the common name for Octadecanoic acid?
Stearic acid
What is the structure for Octadecanoic acid (Steric acid)?
CH3(CH2)16COOH
What is the melting point of Octadecanoic acid (Steric acid)?
69.6 degrees C
What is the systemic name for Palmitoleic acid?
9-Hexadecanoic acid
What is the common name for 9-Hexadecanoic acid?
Palmitoleic acid
What type of lipid is Hexadecanoic acid (Palmitic acid)?
Fatty acid
What type of lipid is Dodecanoic acid (Lauric acid)?
Fatty acid
What type of lipid is Tetradecanoic acid (Myristic acid)?
Fatty acid
What type of lipid is Octadecanoic acid (Steric acid)?
Fatty acid
What is the structure of 9-Hexadecanoic acid (Palmitoleic acid)?
CH3(CH2)CH=CH(CH2)7COOH
What is the melting point of 9-Hexadecanoic acid (Palmitoleic acid)?
-0.5 degrees C
What is the systemic name for Oleic acid
9-Octadecanoic acid
What is the common name for 9-Octadecanoic acid
Oleic acid
What is the structure of 9-Octadecanoic acid (oleic acid)?
CH3(CH2)CH=CH(CH2)COOH
What is the melting point of 9-Octadecanoic acid (oleic acid)?
12 degrees C
Is Hexadecanoic acid (Palmitic acid) a saturated or unsaturated fatty acid?
saturated acid
Is type of lipid is Dodecanoic acid (Lauric acid) a saturated or unsaturated fatty acid?
Saturated acid
Is Tetradecanoic acid (Myristic acid) a saturated or unsaturated fatty acid?
saturated
Is Octadecanoic acid (Steric acid) a saturated or unsaturated fatty acid?
Saturated
Is 9-Octadecanoic acid (oleic acid) a saturated or unsaturated fatty acid?
unsaturated fatty acid in cis
Is 9-Hexadecanoic acid (Palmitoleic acid) a saturated or unsaturated fatty acid?
Unsaturated fatty acid in cis
what is the systemic name for Linoleic acid?
9, 12 Octadecadienoic acid
What is the common name for 9, 12 Octadecadienoic acid?
Linoleic acid
Is 9, 12 Octadecadienoic acid (Linoleic acid) a saturated or unaturated fatty acid?
unsaturated fatty acid in cis
What is the structure of 9, 12 Octadecadienoic acid (Linoleic acid)?
CH3(CH2)4(CH=CHCH2)2(CH2)6COOH
What is the melting point of 9, 12 Octadecadienoic acid (Linoleic acid)?
-5 degrees C
What is the systemic name for alpha-Linolenic acid?
9, 12, 15 Octadecatrienoic acid
What is the common name for 9, 12, 15 Octadecatrienoic acid?
alpha-Linolenic acid
What is the structure of 9, 12, 15 Octadecatrienoic acid (alpha-Linolenic acid)?
CH3CH2(CH=CHCH2)3(CH2)6COOH
What is the melting point of 9, 12, 15 Octadecatrienoic acid (alpha-Linolenic acid)?
-11 degrees C
Is 9, 12, 15 Octadecatrienoic acid (alpha-Linolenic acid) a saturated or unsaturated fatty acid?
Unsaturated fatty acid in cis
How many double bonds does a saturated fatty acid?
No double bonds
What type of fatty acids has double bonds?
unsaturated fatty acids
How are unsaturated fatty acid biosynthesized in eukaryotes?
Biosynthesized in eukaryotes from corresponding saturated fatty acids by an aerobic process.
Linoleic acid and linolenic acid is found where?
plants and fish oils
Linoleic acid and linolenic acid are necessary for what?
regulating blood pressure, clotting, lipid levels, immune response, and inflammation response
Triglycerides from animals are _____ at room temperature and called what?
Triglycerides from animals are solid at room temperature and called fats
Triglycerides from plants and fish are _____ at room temperature and called _____
Triglycerides from plants and fish are liquids at room temperature and called oils.
Phospholipases disrupts what?
disrupts membranes
Bees and snake venom makes a lot of what?
Phospholipase A2
Sphingomyelin is what type of lipid?
sphingolipids
Sphingomyelin has what two components?
1) phosphocholine head group
2) Palmitate residue
Sphingomyelin makes up 10-20% of what?
Plasma membrane
Sphingomyelin is the primary component of what?
myelin sheath
Springosine’s N-acyl fatty acid derivative is called what?
ceramides
sphingolipids are derviatives of what?
C18 amino alcohols sphingosine, dihydrosphingosine and their C16, C17 C19 and C20 homologs.
Ceramides occur only in small amounts in ______ but form the parent compound of the more abundant ______
Ceramides occur only in small amounts in plants and animal tissues but form the parent compounds of more abundant sphingolipids.
What is the most common sphingolipids?
Sphingomyelins
Sphingomyelins contain what?Thus are considered sphingophospholipids.
bear a ceramide bearing either a phosphocholine or a phosphoethanolamine moiety.
the myelin sheath of nerve cells is rich in what?
sphingomyelin
What is the simplest sphingolipid?
Cerebrosides or AKA glucosphingolipids
Cerebrosides are also called what?
glucosphingolipids
Cerebrosides are what?
Ceramides with head groups consisting of a single sugar residue
Galactocerebrosides have a head group of what?
Beta-D-galactose
Galactocerbosides are most prevalent where?
neuronal cell membranes
cerebrosides lack what group?
phosphate group
Glucocerebrosides have what type of head?
Beta-D-glucose
Glucocerbrosides occur where?
In the membranes of other tissues.
What group does phospholipids have cerbrosides lack? Making cebrosides what?
phosphate group making cerebrosides the most frequent nonionic compounds.
The galactose residue of some galactocerebrasides are _____ at what position to form ionic compounds called what?
are sulfated at C3 position to form ionic compounds called sulfatides.
More complex sphingoglycolipids have what?
unbranched oligosaccharides head groups of up to four sugar residues
What are the three types of sphingolipids
1) sphingomyelin
2) Cerebrosides
3) Gangliosides
What is the most complex group of sphingolipids?
Gangliosides
Gangliosides have what types of significance?
physiological and medical
Gangliosides are the primary components of what?
cell surface membranes
Gangliosides constitute a significant fraction of ____ lipids?
brain lipids (6%)
Gangliosides act as what for toxins?
receptors
What is the structure of Gangliosides?
ceramide oligosaccharides that include atleast one sialic acid residue (N-acetylneuraminic acid and its derivatives).
How does complex carbohydrate head groups of gangliosides act?
Their complex carbohydrate head groups, which extend beyond the surfaces of cell membranes, act as specific receptors for certain pituitary glycoprotein hormones that regulate a number of physiological functions.
Disorders of ganglioside break down are responsible for what type of hereditary disesease? which are characterized how?
Sphingolipid storage diseases such as Tay-Sachs disease which are characterized by an invariably fatal neurological deterioration.
GM1 Gangliosides include?
- > D-Galactose
- > N-Acetyl-D-galactosamine
- > D-Galactose
- > D-Glucose
GM2 gangliosides include?
- > N-Acetyl-D-galactosamine
- > D-Galactose
- > D-Glucose
GM3 gangliosides
- > D-Galactose
- > D-Glucose
Gangliosides are specific determinants of cell-cell recognition so they have inportant role in what?
growth and differentiation of tissues as well as in carcinogens (cancer generation).
What is the most common steroid in animals?
Cholesterol
What is the metabolic precursor to steroid hormones?
cholesterol
Steroids are derivatives of what?
cyclopentanoperhydrophenanthrene
Cholesterol is classified as what? why?
sterol because of its C3-OH group and its branched aliphatic side chain of 8 to 10 carbon atoms at C17.
Cholesterol is a major component of what? Present at what mol %.
animal plasma membranes which typically is present at 30-40 mol%
Cholesterol is present in lesser amount than 30-40 mol% in the membranes or what?
membranes of animal sub-cellular organelles.
What gives cholesterol its weak amphiphilic character?
Its polar OH group
What gives cholesterol its rigidity which is greater than other membrane lipids?
its fused ring system.
Cholesterol is abundant is _____ in which ~70% is esterified to what?
abundant in blood plasma lipoproteins where ~ 70% of it is esterified to long-chain fatty acids to form cholesteryl esters.
steroid hormaones regualte what?
a great variety of physiological functions including sexual development and carbohydrate metabolism.
plants contain little cholesterol but rather their most common sterol membrane components are what?
stigmasterol and Beta-sitosterol.
How does cholesterol differ fro, stigmasterol and Beta-sitosterol?
differ only in their aliphatic side chain.
Yeast and fungi have the sterol _____ which has what structure?
erosterol which has a C7 to C8 double bond.
Prokaryotes except for mycoplasmas contain what sterol?
little if any sterol
Gluccorticoids are what?
sterois used for biomolecule metabolism that deal with inflammation and stress