Lipids

Vocabulary flashcards covering lipid classification, fatty acids, complex lipids, membrane structures, steroids, and hormones based on the lecture material.

Lipids

Biological compounds that are soluble only in nonpolar solvents.

2 types of lipids

1. saponifiable/hydrolyzable lipids

2. non-saponifiable/non-hydrolyzable lipids

Saponifiable/Hydrolyzable lipids

Lipids containing esters that are hydrolyzed under basic conditions, categorized into simple and complex lipids.

• biological waxes, TAGs, phospholipids

2 types of saponifiable/hydrolyzable lipids

1. simple lipids

2. complex lipids

Simple lipids

Saponifiable lipids containing one or more fatty acids and an alcohol. (waxes and triglycerides)

Complex lipids

Saponifiable lipids containing more than two types of components, including an alcohol, fatty acids, and additional groups. (phosphoglycerides and sphingoglycerides)

Nonsaponifiable lipids

Lipids that do not contain esters and cannot be hydrolyzed under basic conditions. (steroids and prostaglandins) fat soluble

4 Vitamins (ADEK)

1. A retinol

2. D cholecalciferol

3. E tocopherol

4. K phylloquinone

vitamin A Retinol

vision

vitamin D cholecalciferol

Cn absorption

vitamin E tocopherol

detoxification

vitamin K phylloquinone

blood clotting

eicosanads

signals inflammation (aspirin, ibuprofen, prostaglandins)

5 functions of lipids

1. repel water

2. protective wax coatings in some plants

3. energy rich compounds with low densities

4. energy storage in plants and animals

5. structural component especially in formation of the cellular membrane

Fatty acids

Straight long-chain carboxylic acids serving as building blocks of lipids, featuring a long nonpolar hydrocarbon tail and a hydrophilic carboxyl head ($\text{—COO}^-$) at physiological pH.

• size ranges from 10-20 carbons

• usually gas an even number of carbon atoms

Micelle

A spherical cluster of lipid molecules in which polar chains are on the surface and nonpolar chains are held in the interior by weak dispersion forces.

important for biological functions such as transport of insoluble lipids in blood

2 tyles of fatty acids

1. saturated fatty acids

2. unsaturated fatty acids

Saturated fatty acids

Fatty acids containing no carbon-carbon double bonds ($\text{C=C}$) in their hydrocarbon chains.

• more carbons

• higher melting point

• solid at room temperature

Unsaturated fatty acids

Fatty acids containing one or more carbon-carbon double bonds ($\text{C=C}$), typically in the cis configuration, which causes long kinks or bend in the chain and lowers the melting point.

• more double bonds

• lower melting point

• liquid at room temperature

Essential fatty acids

Fatty acids that cannot be synthesized by the human body and must be acquired through diet.

2 essential fatty acids

1. linoleic acid (omega-3 fatty acids)

2. linolenic acid (omega-6 fatty acids)

linoleic (omega-3 fatty acids) and linolenic (omega-6 fatty acid) acid

bad cholesterols used to produce hormone-like substances that regulate blood: pressure, clotting, lipid levels and immune and inflammation responses

fats and oils

esters that contain an alcohol portion derived from glycerol and an acid portion furnished by fatty acids

Triglycerides or triacyglycerols

fats and oils formed by the esterification of fats and oils

natural triglycerides

mixtures of different triglyceride molecules

Fats

• Animal-derived esters

• long-chain saturated fatty acids

• solids at room temperature.

Oils

• Plant- and fish-derived esters

• unsaturated fatty acids

• liquids at room temperature.

lipase

emulsifies liquid

excessive dietary fat

influences the development id chronic diseases raising blood cholesterol levels

high cholesterol

risk factor in the development of coronary heart disease, a leading cause of death of Americans every year

3 reactions of fats and oils

1. hydrolysis

2. saponification

3. hydrogenation

hydrolysis

• important for digestion of fats and oils

• results in formation of glycerol and fatty acids

• can be catalyzed by enzymes (lipases) of the digestive system

Saponification

The chemical process of reacting triglycerides with a strong base to yield glycerol and fatty acid salts (soaps).

2 soap bases

1. sodium/hard salts

2. potassium/soft salts

sodium/hard salts

cake soaps

potassium/soft salts

shaving cream and liquid soap

NaOH

strong base for soap

traditional soap making

• uses animal fat as source of triglycerides

• uses lye (crude NaOH) or an aqueous extract of wood ash as the base

• was lost in the fall of the Roman Empire

soapless centuries (500-1500 AD)

had plagues that nearly depopulated an unsanitary western europe

Hydrogenation

A reaction that converts double bonds in fatty acids into single bonds

• decreasing the degree of unsaturation

• increases the melting point.

2 types of hydrogenation

1. complete hydrogenation

2. partial hydrogenation

complete hydrogenation

results in a hard and waxy product

partial hydrogenation

results in a smooth and creamy product

trans fatty acids

• fatty acid molecules in the cis configuration isomerized

• consumption raises blood cholesterol levels

Waxes

Water-insoluble esters composed of long-chain fatty acids and long-chain alcohols that serve as protective coatings in nature (skin, fruits, leaves, and fur)

• also used to make cosmetics, candles, ointments, and protective polishes

beeswax

most common wax, only edible if from honey bees

Phosphoglycerides

Complex phospholipids that contain

1. glycerol

2. fatty acids

3. phosphoric acid

4. amino-alcohol groups (choline, ethanolamine, serine)

2 phosphoglycerides/phospholipids

1. lecithins

2. cephalins

Lecithins (phosphatidylcholine)

• phosphoglycerides containing choline

• outside

• important structural components of cell membranes

• acts as emulsifying and micelle-forming agents.

Cephalins (phospatidylethanolamine)

• Phosphoglycerides containing ethanolamine or serine

• abundant in brain tissue and blood platelets

• acts as emulsifiers.

Sphingolipids

Complex lipids that contains sphingosine rather than glycerol

Sphingosine

A long-chain unsaturated aminoalcohol that serves as the core structural component of sphingolipids.

2 types of sphingolipids

1. sphingomyelin

2. glycolipid

Sphingomyelin

A sphingolipid consisting of sphingosine, a fatty acid, phosphate group, and choline group

• connected via an amide linkage and found in the myelin sheath.

Glycolipids

• known as cerebrosides because of its abundance in brain tissue

• no phosphate group.

3 sphingolipids diseases

1. tay-sachs

2. gauchers

3. niemann-pick

Tay-Sachs disease

An inherited enzyme-deficiency disorder resulting in the abnormal accumulation of ganglioside GM2 glycolipids in the brain.

Gaucher's disease

An inherited enzyme-deficiency disorder characterized by the accumulation of glucose-containing cerebrosides in the spleen and liver.

Niemann-Pick disease

An inherited enzyme-deficiency disorder leading to the abnormal accumulation of sphingomyelins in several organs particularly the liver and spleen.

2 cell types

1. prokaryotic cells

2. eukaryotic cells

prokaryotic cells

simple unicellular organisms that has no nucleus or membrane-enclosed organelles

eukaryotic cells

contains membrane-enclosed organelles nucleus

7 cellular organelle

1. endoplasmic reticulum

2. lysosome

3. microfilaments and microtubules

4. mitochondrion

5. nucleus

6. plastids

7. ribosome

endoplasmic reticulum

synthesis of proteins, lipids and other substances

lysosome

digestion of substance taken into cells

microfilaments and microtubules

cellular movement

mitochondrion

cellular respiration and energy production

nucleus

contains DNA that directs protein synthesis

plastids

contains plant pigments such as chlorophyll (photosynthesis)

ribosome

protein synthesis

2 cell membranes

1. internal cell membrane

2. external cell membrane

internal cell membrane

surround some organelles creating cellular compartments that has separate organization and functions

external cell membrane

a selective barrier between a living cell and its environment

membrane structure

60% lipids and 40% protein

lipids includes:

1. phosphoglycerides

2. sphingomyelin

3. cholesterol

Fluid-mosaic model

A model of membrane structure where proteins are embedded in a flexible lipid bilayer

• hydrophobic chains inside

• hydrophilic groups outside

• increases the flexibility or fluidity of the membrane

repulsion

when lipid bilayer is broken and tails are exposed to water it results in this, then reforms and breaks the seals spontaneously

lipid bilayer

proteins either float or extend in this

lipid molecules

free to move laterally in the bilayer

Steroids

broad class that contain 4 fused carbon rings. (tetracyclic structure)

• soluble in nonpolar solvents

• includes cholesterol and bile salts

terpenes

steroid precursor (carotenoid vitamins)

steroid precursor

cholesterol

Cholesterol

The most abundant steroid in the human body, essential component in cell membranes and precursor for other important steroids (squalene or triterpene)

• present in food and synthesized in the liver

atherosclerosis

hardening of arteries

Bile

yellowish-brown or green liver secretion that is stored and concentrated in the gallbladder

• fatty foods enter the small intestine, concentrated in the gallbladder, and empties bile into the intestine

2 bile chief constituents

1. bile salts

2. waste components

sodium glycocholate

principal bile salt

bile salts

emulsification of lipids in the intestine by breaking large lipid globules into smaller droplets

• emulsification of cholesterol found in bile

• hydrolysis reactions

• high levels can lead to formation of gallstones

waste components

cholesterol and bile pigments

Gallstones

can become lodged in the bile ducts and prevent it from passing into the duodenum which prevents normal digestion of fats resulting in:

• pain

• nausea

• yellow skin because of bile pigments in the blood

• gray stool because of lack of bile pigments

hormones

chemical messenger of specific glands

3 steroid hormones

1. adrenocorticoid hormones

2. mineralocorticoids

3. glucocorticoids

adrenocorticoid hormones

produced by adrenal cortex and classified in the basis of function

Mineralocorticoids

regulate the concentration of ions in bodily fluids

Glucocorticoids

enhanced carbohydrate metabolism, inhibits the inflammation caused by prostaglandins

sex hormones

produced in the testes for men, and ovaries in women

4 sex hormones

1. androgens (testosterone)

2. estrogen

3. progesterone

4. prostaglandins

Androgens

Male sex hormones produced by the testes, such as testosterone, that drive the development of male genital organs and secondary sex characteristics.

Androgens

growth promoting steroids, synthetic derivatives of testosterone that promote muscular development used by athletes

• side effects includes from acne to deadly liver tumors

Estrogen

Female sex hormones, including estradiol and estrone, responsible for egg development and female secondary sex characteristics.

Estrogen

Female sex hormones, including estradiol and estrone, responsible for egg development and female secondary sex characteristics.