L.6 Carbohydrates & Lipids 2

Question 1

Four types of structural Lipids

Answer 1

1. Phospholipids
2. Glycerophospholipids
3. Sphingolipids
4. Waxes

Question 2

Four Types of Signaling Lipids

Answer 2

1. Terpenes & Terpenoids
2. Steroids
3. Prostaglandins
4. Fat Solube Vitamins (DEAK)

Question 3

Two Energy Storage Lipids

Answer 3

1. Triacylglycerides
2. Free Fatty acids & Saponification

Question 4

Four Characteristics of Lipids

Answer 4

1. Insoluble in Water
2. Soluble in non-polar solvents
3. The major component of the phospholipid bilayer
4. Amphipathic; 1 molecule half hydrophobic half hydrophilic

Question 5

Phospholipids Structure and Interaction with Environment

Answer 5

• Hydrophilic polar head & a hydrophobic tail
• Head group attached by Phosphodiester Linkages
• Head (Interacts with environment determines function/+ - N)
• Saturation of fatty acid determines the fluidity of the membrane
• BACKBONE = Where fatty acid tails attached
  
  • Classified accordingly
    
    • Glycerols = 3 Carbon Alcohol (phosphoglycerides/glycerophospholipids)
    • Sphingosine = Sphingolipid (not all are phospholipids)

Question 6

Sphingolipid Structure & Interaction with Environment

Answer 6

• Blood typing (cell surface antigen)
• Sphingosine or sphingoid backbone
• Phosphodiester linkages
• or Glycosidic linkages to sugars = GLYCOLIPID
  
  • glycosphingolipids
  • Cerebroside = 1 sugar
  • Globosides 2 sugars or more

Question 7

Sphingolipids

Four major Classes

Answer 7

1. Ceramides
2. Sphingomyelin
3. Glycosphingolipids
4. Gangliosides

Question 8

Ceramides

Structure and Function

Answer 8

Single Hydrogen Atom @ head

• Ceramides are a family of waxy lipid molecules.
• A ceramide is composed of sphingosine and a fatty acid.
• Found in high concentrations within the cell membrane of eukaryotic cells, since they are component lipids that makeup sphingomyelin, one of the major lipids in the lipid bilayer

Question 9

Sphingomyelin

Structure & Function

Answer 9

• It usually consists of phosphocholine and ceramide, or a phosphoethanolamine head group;
• No Net Charge
• In plasma membrane of cells producing myelin

Question 10

Glycosphingolipids

Answer 10

• Attached to sugar moieties instead of phosphate groups
• Cerebrosides = 1 sugar
• Globosides = 2 sugars or more
• Neutral at natural pH
• AKA Glycolipid

Question 11

Gangliosides

Structure & Function

Answer 11

• Glycolipids
• Most complex
• Polar head group (oligosaccharides)
• with at least one terminal N-acetylneuraminic acid (NANA); also called Sialic Acid)
• At terminus - charge
• No phosphate group
• cell-cell interaction
• cell recognition
• signal transduction

Question 12

Waxes

Structure & Function

Answer 12

• Esters of long-chain
• fatty acids with long chain alcohols
• Used for protection against water evaporation and parasites in plants and animals

Question 13

Signaling Lipids (5 Bullet Points)

Answer 13

• Cellular signaling co-enzymes in Electron Trasport Chain
• Hormones
• Intracellular Messengers responding to extracellular messages
• Conjugated pi bonds that absorb light
• pigments

Question 14

Terpenes and Terpenoids

Answer 14

Terpenes; are odiferous steroid precursors made from isoprene,

a five-carbon molecule

• One terpene unit (monoterpene) contain two isoprene units

Terpenoids are derived from terpenes via oxygenation or backbone rearrangement. They have similar odorous characteristic

Question 15

Steroids

Answer 15

Metabolic derivatives of Terpenes

• 4 cycloalkane rings
• 3 cyclohexane
• 1 cyclopentane
• Functionality determined by oxidation and status of the rings and functional groups
• A large number of H and C makes them non-polar

Question 16

Steroid Hormones

Answer 16

Steroid Hormones; have high-affinity receptors, work at low concentrations, and affect gene expression and metabolism

Testosterone

Estrogen

Cortisol

Aldosterone

They are secreted by three “steroidglands”—the adrenal cortex, testes, and ovaries—and during pregnancy by the placenta. All steroid hormones are derived from cholesterol.

Question 17

Cholesterol

Answer 17

Important for membrane fluidity and stability; it serves as a precursor to a host of other molecules

Question 18

Prostaglandins

Answer 18

Are autocrine and paracrine signaling molecules that regulate cyclic adenosine monophosphate (cAMP) levels. They have powerful effects on smooth muscle contraction, body temperature and sleep-wake cycles, fever, and pain.

• Made by all cells in the body
• 20 carbon molecules
• unsaturated carboxylic acids
• derives from arachnoid acid
• contain 1 5-carbon ring

cAMP; Intracellular messenger mediating actions of many hormones.

COX (cyclooxygenase)

Aids in Production of prostaglandins

NSAIDs inhibit this enzyme

Question 19

Vitamin A

Answer 19

• Carotene
• unsaturated hydrocarbon
• vision
• growth
• development
• immune
• A significant metabolite of vitamin a is the Aldehyde for RETINAL
  
  • RETINAL; Component of the light sensing molecular system
  • RETINOL; Storage form and it is oxidized to RETINOIC ACID
  • RETINOIC ACID; Hormone that regulates gene expression during epithelial development

Question 20

Vitamin D

Answer 20

• Cholecalciferol
• Consumed in the form of u-v light-driven skin reaction
• In the liver and kidney converted to calcitriol, the biologically active form
• calcitriol increases calcium and phosphate reuptake in the intestines which promote bone production.

Question 21

Vitamin E

Answer 21

• Tocopherols & Tocotrienols
• Biological antioxidants (aromatic ring captures free radicals)
• Prevent oxidative damage (Cancer & Aging)

Question 22

Vitamin K

Answer 22

• Phylloquinone K1 and Menaquinones K2
• Important for the formation of PROTHROMBIN, a clotting factor.
• It performs post-translational modifications on a number of proteins, creating calcium-binding sites.

Question 23

Triacylglycerols (triglycerides)

Answer 23

Top preferred method of storing energy for long-term used.

• Contain one glycerol attached to 3 fatty acids by ester bonds.
  The fatty acid usually varies within the same triacylglycerol.
• 2X as much energy per gram during oxidation; the carbons on the fatty acids (lipids) are more reduced (more negative), than those of carbohydrates.
• Very hydrophobic, not hydrated by the body water and therefore do not carry additional water weight.

Question 24

Adipocytes

Answer 24

Animal cells specifically used for the storage of

LARGE triacylglycerols deposits.

• Under Skin
• Mammary Glands
• Abdomen Cavity
• Free fatty acids travel bi-directional in the bloodstream between liver & adipose tissue.
• ID’d by the level of saturation/unsaturation
• Salts of free fatty acids are soaps; synthesized in saponification

Question 25

Saponification

Answer 25

Saponification is the ester hydrolysis of triacylglycerols using a strong base, like sodium or potassium hydroxide

Question 26

Micelle

Answer 26

Soaps act as surfactants, forming micelles. A micelle can dissolve a lipid-soluble molecule in its fatty acid core, and washes away with water because of its shell of carboxylate head group (hydrophilic).