Lipids

What differentiates a sulfatide from other sphingolipids?

A sulfatide are cerebrosides that have been sulfated.

Name the 4 vitamins that are lipids

A, D, E, K "DEAK"

Pfizer has made zillions of bucks selling Viagra (sildenafil citrate). Before Viagra was on the market, Caverject (alprostadil, Upjohn) was an effective treatment for the same indication. Why did Caverject's lipid nature keep it from becoming as popular?

Caverject is prostaglandin E1 in a form suitable for injection. Caverject was required to be injected locally into the site it acted upon because prostaglandins only act locally in the body due to their lipid nature.

Name three sphingolipids that are glycosphingolipids.

Ceerebrosides, gangliosides, and sulfatides have sugar head groups.

Name two sphingolipid classes that are not glycosphingolipids (don't have sugar (carbohydrate) head groups)

Ceramides (no charge on head group) and sphingomyelins (positive charge on head group) do not have sugar head groups.

What is fatty and acidic about fatty acids?

FAs are composed of a lipid (fat) and an acid on the terminal carbon. The unbranched hydrocarbon chain, creating the hydrophobic nature, causes the fatty characteristic. The ionizble carboxyl group causes the acidic nature.

Do you expect any lipid hormones or fatty acids to be free in the blood?

FAs would be free in the blood, which is an aqueous solution. (FAs are bound to albumin to some extent) Lipids however must be attached to binding proteins in order to circulate the loud.

8 diseases caused by defects in sphingolipid degradation

Fabry's, Fucosidosis, Gangliosidosis, Gaucher's, Krabbe's, Niemann-Pick, Sndhoff's, and Tay-Sach's

What are two cell types that have significant glycosphingolipids in their plasma membrane?

Neural cells and erythrocytes have glycosphingolipids in their plasma membranes.

What is the importance of the phosphate group in a phospholipid?

Phosphate group polarizes the head of the lipid, creates the amphiphilic nature. this is necessary for the cell membrane bilayer permeability.

Name the 3 classes of lipids of which the lipid bilayer membrane is composed

Phospholipids (sphingolipids), steroids (hormones), and eicosanoids are composed of the lipid bilayer membrane

Why do saturated FAs have higher MPs than unsaturated FAs?

Saturated fats create a larger overall structure with only single bonds, which is easier to break down than the linear structure of the unsaturated fats with double bonds. The unsaturated fatty acids are usually of lower melting point than the saturated, and hence as a rule the saturated fats are likely to be solid, whereas the unsaturated fats are oils.

What feature of sphingolipids allows them to be specifically recognized by hormones and blood borne antigens?

The different sugar configurations allow for the specific recognitions.

Volatile anesthetics (general anesthesia delivered by inhalation such as halothane and enflurane) tend to be hydrophobic. How do they work?

Their site of action is in hydrophobic pockets of membrane bound vesicles.

Describe 3 strategies employed by lipids that allow them to carry out a function despite their repulsion to water.

They act as barriers or energy stores. They can interact with polar molecules through their own polar groups or by complexing with proteins, and have only local effects since they cannot be carried away by aqueous fluids.

There are no binding proteins that chaperone eicosanoids through the circulation. How do they accomplish their function despite this?

They act on neighboring cells and therefore do not need to circulate through the blood.

What are two roles of glycosphingolipids in humans?

They are responsible for blood groups and function in neural cell plasma membranes. Gangliosides are configured to be specifically recognized as receptors and are involved in cell-cell recognition.

Describe the lipid bilayer membrane.

amphipilic with hydrophilic head facing the exterior of the membrane and a hydrophobic tail which faces the hydrophobic tail of the second layer of the membrane.

Mechanism of aspirin action

aspirin inhibits the initial step of the cyclic pathway of prostaglandins, which is the cycloxygenase activity. This results in the restriction of pain signals.

Describe the mechanism of bile acids and salts relative to their role in digestion

bile acids break down the chyme of food particles which allows the lipid droplets to attach to more surface are of the food particles to enhance digestion

biological functions of lipids?

composition of the cell membrane, an energy source, vitamins, pulmonary surfactants, insulation, signaling, anchoring proteins to the membrane, pigmentation, and digestion

name 5 types of steroid hormones

estrogens, androgens, progestins, glucocorticoids, mineral corticoids

Define hydrophobic and hydrophilic

hydrophobic is water fearing. nonpolar molecules are hydrophobic because they have an even sharing of e-. Hydrophilic is water loving. polar molecules are hydrophilic because they have an uneven sharing of e- and can bind to oxygen, charged groups, and water.

Name the classes of lipids

include fatty acids, triacylglycerols, phospholipids, sphingolipids, steroids, eicosanoids, and vitamins

What are the four classes of eiosanoids?

prostaglandins, prostacyclins, thromboxanes, and leukotrienes

Name the class of disease associated with sphingo lipid metabolism

sphingolipid storage diseases

Why do triglycerols make such good forms of energy storage?

they are less oxidized than carbs and proteins, and stored in the anhydrous form (away form water), and have a larger energy per molecule ratio

Explain why lipids don't mix well with water

water is a polar substance and lipids are non polar and hydrophobic.

What defines a lipid?

waxy, oily substance that is not water soluble (hydrophobic)

2 sites of body where lipid accumulates with ill effects

when deposited in the arteries, lipids can cause cardiovascular diseases such as M1 and arteriosclerosis. when deposited in the fat cells (adipocytes) it can lead to cardiovascular diseases in addition to obesity and risk of diabetes

Name the essential FAs

α-linolenate and either linoleate or gamma-linolenate. Humans cannot synthesize these fatty acids and must receive the enzymes to break them down through diet (plants).