lipids (summer biochem)

What is an important function of thromboxanes?


Promote the formation of blood clots

What produces thromboxanes?


Blood platelets

What do thromboxanes promote?


Platelet aggregation

Elevated levels of what are associated with inflammatory and hypersensitivity responses?


Leukotrienes

Where are prostaglandins made?


Sites of tissue damage or infection

What processes do prostaglandins control?


Inflammation, blood flow, blood clots, induction of labor

How does aspirin work?


By inhibiting prostaglandin production

What kind of derivative are eicosanoids?


Oxygenated C20-fatty-acid

What function do eicosanoids have?


Messenger lipid

What is the role of eicosanoids?


The inflammatory response
The production of pain and fever
The regulation of blood pressure
The induction of blood clotting
The control of reproductive functions
The regulation of the sleep/wake cycle

What do bile salts emulsify in the bile?


Cholesterol

What causes cholesterol to precipitate and form gallstones?


Cholesterol levels are too high

What can gallstones block?


The duct that allows bile secretion

What happens when fats are no longer digested properly due to gallstones?


Bile pigments absorbed, skin becomes yellow
Stool becomes gray

What happens when fats are no longer digested properly due to gallstones?


Where is testosterone primarily produced?


What is testosterone's purpose in men?


Maintain healthy muscle mass, stamina, and strength

Where is progesterone naturally produced?


What is progesterone responsible for?


Regulation of the monthly menstrual cycle

What is progesterone responsible for?


Ceasing the menstrual cycle during pregnancy

What is the main function of estradiol?


Mature and maintain the reproductive system

What do increased estradiol levels cause during the menstrual cycle?


Maturation and release of the egg

What do increased estradiol levels cause during the menstrual cycle?


Thickening of the uterus lining

Where is bile produced?


Where is bile stored?


Gall bladder

What do bile salts do?


Break fats into smaller pieces

Why do bile salts break fats into smaller pieces?


Allows them to be hydrolyzed more easily

What do sex hormones produced in the testes and ovaries regulate?


Production of sperm and eggs

What do sex hormones produced in the testes and ovaries aid in?


Development of secondary sex characteristics

What do mineralocorticoids regulate?


Ion concentration

What ion concentration do mineralocorticoids mainly regulate?


Na+ (sodium)

What does aldosterone influence?


Absorption of Na+ (sodium)

What does aldosterone influence?


What does aldosterone regulate?


Where are adrenocorticoid hormones produced?


Adrenal glands

What do glucocorticoids affect?


Metabolism of carbohydrates

What are cortisol, cortisone, and prednisolone used to treat?


Why are steroids classified as lipids?


They are soluble in nonpolar solvents

Why are steroids nonsaponifiable?


Components are not held by ester linkages

What does the basic steroid structure contain?


Four fused rings

What is the most abundant steroid in the body?


What is cholesterol a precursor for?


What condition is correlated with high levels of cholesterol in the blood?


Atherosclerosis

What causes the membrane to re-form when it is broken?


Repulsion between the nonpolar portion and water

How do some proteins exist in the membrane?


Float in the lipid bilayer like icebergs

How do some proteins exist in the membrane?


Extend through the bilayer

Approximately what percentage of cell membranes is proteins?


What is the cell membrane composed of according to the fluid-mosaic model?


According to the fluid-mosaic model, where do the nonpolar tails of lipids point?


Towards the interior of the bilayer

According to the fluid-mosaic model, where do the polar, hydrophilic portions point?


What kind of lipids are glycolipids?


Sphingolipids

What do glycolipids contain?


Carbohydrates

What are glycolipids also referred to as?


Cerebrosides

Why are glycolipids also referred to as cerebrosides?


Abundance in brain tissue

What type of lipid is sphingolipid?


Second type of lipid in membranes

Where are sphingolipids particularly found?


Nerve cells and brain tissues

What groups are attached to the base sphingosine in sphingomyelin?


Fatty acid to the amine

What groups are attached to the base sphingosine in sphingomyelin?
 (other)

Phosphate attached through ester bond

What groups are attached to the base sphingosine in sphingomyelin?
 ( the other 2)

Phosphate through ester bond to choline

What aminoalcohols do cephalins contain?


Ethanolamine or serine

What aminoalcohols do cephalins contain?


Ethanolamine or serine

Where are cephalins found?


Most cell membranes

Where are cephalins particularly abundant?


Brain tissue

Where else are cephalins found?


Blood platelets

Where else are cephalins found?


Blood platelets

What role do cephalins play?


Blood clotting

Which end of lecithin is highly hydrophilic?


End with negatively charged oxygen

Which end of lecithin is highly hydrophilic?


End with positively charged nitrogen

What part of lecithin is hydrophobic?


Rest of the molecule

What does lecithin act as?


An emulsifying agent

What is one way lecithin acts as an emulsifying agent?


Forms important structural component of cell membranes

What is one way lecithin acts as an emulsifying agent?


Forms micelles for lipid transport

Where does lecithin extracted from soybeans work?


Margarine and candies

Why is lecithin added to margarine and candies?


Provide a smooth texture

What amino alcohol does lecithin contain?


Choline

Why are there different possible lecithins?


Variable fatty acids at first and second positions

What kind of lipids are phosphoglycerides?


Complex

What are phosphoglycerides major components of?


Cell membranes

What are phosphoglycerides also called?


Phospholipids

What alcohols are attached to the phosphate group in phosphoglycerides?


Choline, ethanolamine, or serine

What kind of lipids are waxes?


What two components do waxes contain?


What is the chain length of alcohol in waxes?


12-32 carbons

Why do waxes often occur?


Protective coatings

Where do waxes often occur?


On feathers, fur, skin, leaves, and fruits

What kind of alcohols are waxes esters of?


Long chain monohydric alcohols

What does sebum contain?


Waxes

Where is sebum secreted from?


Sebaceous glands of the skin

What do waxes in sebum help do?


Keep skin soft and prevent dehydration

What is wax used commercially to make?


Cosmetics, candles, ointments, and protective polishes

What are alkenes converted into in hydrogenation reactions?


Alkanes

What gasses are used in hydrogenation reactions?


Hydrogen

What kind of catalyst is used in hydrogenation reactions?


Pt, Ni, or some other metal

What is hydrogenation used to convert?


Unsaturated to saturated fatty acids

In partially hydrogenated vegetable oils, what happens to some cis double bonds?


Twists into trans isomers

What kind of soap does NaOH produce?


Hard