Lipid Structure and Function

Question 1

Amphipatic Molecule

Answer 1

molecule with both hydrophobic and hydrophillic regions

ie. lipids

Question 2

When placed in aqueous solutions, lipids form structures that all the ______ regions to group internally while the _______ regions interact with water.

Answer 2

hydrophobic

hydrophillic

Question 3

Phospholipids

Answer 3

phosphate and a alcohol containing a polar head group and hydrophobic fatty acid tail connected via phosphodiester linkage

clasified according to backbone of the molecule

Question 4

Glycerol

Answer 4

three carbon alcohol that forms:

phosphoglycerides
glycerophospholipids

Question 5

NOT all sphingolipids are ________

Answer 5

phospholipids

Question 6

______ and _____ determine how an overall molecule will behave.

Answer 6

Saturation and Length

Question 7

Fully Saturated Fatty Acid

Answer 7

only single bonds, no pi bonds (double bonds)

have greater van der Waals Forces and stable overall structure meaning they are solids at room temp (think butter)

Question 8

Unsaturated Fatty Acid

Answer 8

includes one or more double bonds which intrudce kinks making it hard to stack/solidify making them liquids at room temp (oils)

Question 9

Phospholipids with _____ fatty acids are more fluid regions of the phospholipid bilayer.

Answer 9

unsaturated

Question 10

Glycerophospholipids/Phosphoglycerides

Answer 10

phospholipids with a glycerol backbone bonded to two fatty acids via ESTER linkage and phosphodiester linkage to a polar head group

named according to head group (can be + neutral or - charged)

within each subtype, FA chain length and saturation can vary

Question 11

Phosphatidylcholine

Answer 11

phosphoglyceride with a choline head group

Question 12

Phosphatidylethanolamine

Answer 12

phosphoglyceride with a ethanolamine head group

Question 13

Sphingolipids

Answer 13

ABO blood typing determined by cell surface antigens which are sphingolipids

sphingosine backbone with long chain non polar fatty acid tails and polar head groups

can be phospholipid if they contain a phosphodiester bond

others have glycosidic linkages to sugar instead of phosphodiester linkages

4 Classes:

• Ceramide
• Sphingomyelins
• Glycolipids
• Gangliosides

Question 14

Glycolipid

Answer 14

any lipid linked to a sugar via glycosidic linkage

Question 15

Ceramide

Answer 15

simplest sphingolipid

single H as its head group

Question 16

Sphingomyelins

Answer 16

major class of sphingolipids that are also phospholipids

either have phosphatidylcholine or phosphatidylethanolamine as head groups meaning they have a phosphodiester bond

no net charge head groups

major component of cell membrane for cells producing myelin (Schawn and Oligodendrocytes)

Question 17

Glycosphingolipids/Glycolipids

Answer 17

have head groups composed of sugars bonded by glycosidic linkages ; no net charge

no phosphodiester linkage so they aren;t phospholipids

on outer surface of the plasma membrane and can be further classified as cerebrosides or globosides

Question 18

Cerebrosides

Answer 18

glycolipids with single sugar

Question 19

Globosides

Answer 19

glycolipids with two or more sugars

Question 20

Gangliosides

Answer 20

most complex sphingolipids

polar head groups made of oligosaccahrides with one or more N-acetylneuraminic acid (sialic acid) molecules at terminus and a negative charge

considered glycolipids with glycosidic linkages

cell interaction, recognition and signal transduction

Question 21

Waxes

Answer 21

esters of long chain fatty acids with long chain alcohols

solids at room temp

protection for animals (prevent dehydration/lubrication) and plants (also help with excessive evap)

Question 22

Lipids serve the following roles:

Answer 22

structure, cellular signaling, coenzymes and energy storage

Question 23

Terpenes

Answer 23

metabolic precursors to steroids and other lipid signaling molecules

built from isoprene (C5H8) moieties with structural pattern of carbons grouped in multiples of 5

scented for protection for insects/plants

Question 24

Monoterpenes

Answer 24

two isoprene units, abundant in oils and terpentine

Question 25

Sesquiterpenes

Answer 25

three isoprene units

Question 26

Diterpenes

Answer 26

four isoprene units where Vitamin A is one of them

Question 27

Triterpenes

Answer 27

six isoprene units -> becomes various steroids and cholesterols

Question 28

Tetraterpenes

Answer 28

8 isoprene units -> B carotene and lutein (Carotenids)

Question 29

Terpenoids/Isoprenoids

Answer 29

derivatives of terpenes that have undergone oxygenation/rearrangement of carbon skeleton modified by functional groups precursor molecule like Terpenes to feed into pathways to produce steroids and influence biological function

Question 30

Steroids

Answer 30

metabolic derivatives of terpenes with the following structure: 4 cycloalkane rings fused together: 3 cyclohexanes and one cyclopentane functionality is determined by the oxidation status of these rings and functional groups nonpolar due to large number of carbons and hydrogens

Question 31

Steroid Hormones

Answer 31

steroids that act as hormones that are secreted by endocrine glands and travel on protein carriers to bind to receptors biological signals capable of regulating metabolism and gene expression

Question 32

Cholesterol

Answer 32

steroid component of phospholipid bilayer that mediates membrane fluidity amphipathic molecule that has constant fluidity in the membrane Low temps: keeps membrane from solidifying High Temps: keeps membrane from being too permeable precursor to many molecules

Question 33

Prostaglandins

Answer 33

20 carbon unsaturated carboxylic acids from arachidonic acid and contain a five carbon ring paracrine/autocrine signaling molecule regulate cAMP synthesis which impacts other hormone actions effect smooth muscle function, influence over sleep cycle and elevation of body temp during fever

Question 34

Vitamin

Answer 34

essential nutrient unable to be synthesized by the body

Question 35

Vitamin A

Answer 35

Lipid soluble carotene, unsaturated hydrocarbon for vision, growth and immune function aldehyde form retinol is important for light sensiing part of human eye stored as Retinol, oxidized to retinoic acid to regulate gene expression

Question 36

Vitamin D

Answer 36

lipid soluble cholecalciferol, UV reaction in the skin Vitamin D gets convereted to calcitrol (active form) in liver/kidneys to increase calcium ad phosphate uptake to promote bone production lack causes rickets, curved bones and impeded growth

Question 37

Vitamin E

Answer 37

lipid soluble tocopherols and tocotrenols aromatic ring with a long isoprenoid side chain and are hydrophobic biological antioxidants that destroy free radicals to prevent oxidative damage

Question 38

Vitamin K

Answer 38

lipid soluble phylloquinone and menaquinones vital for posttranslational modificatiions required to form prothrombin as clotting factor in blood introduces calcium binding sites on calcium binding proteins

Question 39

Triacylglycerols

Answer 39

class of lipids used for energy storage three fatty acids bonded by esterlinkages to glycerol (usually different FAs) non polar and hydrophobic polarity is decreased as the polar hydroxyl groups and carboxylates of fatty acids are bonded together travel between liver and adipose tissue characteristics dependent on the saturation of FA chains

Question 40

Why are lipids good for storage?

Answer 40

carbon atoms of fatty acids are more reduced than sugars which have numberous alcohol groups which means they yield twice as much energy (more energy dense) hydrophobic to decrease weight and need for hydration

Question 41

Adipocytes

Answer 41

special cells which store fats and found under skin, abdominal cavity and mammary glands

Question 42

Free Fatty Acids

Answer 42

unesterified fatty acids with free carboxylate group circulate in blood noncovalently bonded to albumin

Question 43

Saponification

Answer 43

ester hydrolysis of triacylglycerols using strong base (lye aka sodium or potassium hydroxide) sodium slat of fatty acid and glycerol left is the soap

Question 44

Surfactant

Answer 44

lowers surface tension of the surface of a liquid making it a detergent/emulsifier

Question 45

Colloid

Answer 45

formed when aqueous solution and oil mix (usually due to introduction of soap)

Question 46

Micelles

Answer 46

tiny aggregates of soap with hydrophobic tails inward and hydrophillic heads outward which allows for solvation (reason why colloids are made) nonpolar compounds dissolve in hydrophobic interior of ater solluble micelle, meaning cleaning agent can dissolve both water soluble and water insoluble messes and wash them away important for absorption of fat soluble vitamins and complex lipids like lecithins can increase SA for lipolytic enzymes.