Biochemistry Ch 5. Lipid Structure and Function

Question 1

Lipids

Answer 1

Insoluble in water and soluble in nonpolar organic solvents

Question 2

Phospholipids

Answer 2

Amphipathic and form the bilayer of biological membranes, contain a hydrophilic (polar) head group and hydrophobic tails (non polar)

Question 3

Phosphodiester linkage

Answer 3

Attaches hydrophilic head group of phospholipids

Question 4

Phospholipid head group

Answer 4

Attached by a phosphodiester linage and determines the function of the phospholipid because it interacts with the environment

Question 5

Saturation levels

Answer 5

The saturation of fatty acid tails determines the fluidity of membranes, saturated fatty acids are less fluid than unsaturated ones, fatty acids for most of the structural thickness of the phospholipid bilayer

Question 6

Glycerophospholipids

Answer 6

Phospholipids that contain a glycerol backbone

Question 7

Sphingolipids

Answer 7

Contain a sphingosine or sphingoid backbone, many are sphinophospholipids

Question 8

Sphingophospholipids

Answer 8

Sphingolipids that are also phospholipids

Question 9

Sphingomyelins

Answer 9

Major class of sphingophospholipids and contain a phosphatidylcholine or phosphatidylethanolamine head group, are the major component of the myelin sheath

Question 10

Glycosphingolipids

Answer 10

Attached to sugar moieties instead of a phosphate group

Question 11

Cerebrosides

Answer 11

Have one sugar connected to sphingosine

Question 12

Globosides

Answer 12

Have two or more sugars connected to sphingosine

Question 13

Gangliosides

Answer 13

Contain olifosaccharides with at least one terminal N-acetylneuraminic acid (NANA)

Question 14

Waxes

Answer 14

Long chain fatty acids esterified to long-chain alcohols, used as protection against evaporation and parasites in plants and animals

Question 15

Terpenes

Answer 15

Odiferous steroid precursors made from isoprene, a five carbon molecule

Question 16

Monoterpene

Answer 16

One terpene unit, contains two isoprene units

Question 17

Terpenoids

Answer 17

Derived from terpenes via oxygenation or backbone rearrangement, have similar odorous characteristics

Question 18

Steroids

Answer 18

Contain three cyclohexane rings and one cyclopentane ring, their oxidation state and functional groups may vary

Question 19

Steroid hormones

Answer 19

Have high affinity receptors, work at low concentrations, and affect gene expression and metabolism

Question 20

Cholesterol

Answer 20

A steroid important to membrane fluidity and stability, serves as a precursor to a host of other molecules

Question 21

Prostaglandins

Answer 21

Autocrine and paracrine signaling molecules that regulate cAMP levels, have powerful effects on smooth muscle contraction, body temperature, the sleep-wake cycle, fever, and pain

Question 22

Fat soluble vitamines

Answer 22

Include A,D,E and K

Question 23

Vitamin A

Answer 23

aka carotene, metabolized to retinal for vision and retinoid acid for gene expression in epithelial development

Question 24

Vitamin D

Answer 24

aka cholecalciferol, metabolized to calcitriol in the kidneys and regulates calcium and phosphorus homeostasis in the intestines (increasing calcium and phosphate absorption), promoting bone formation, deficiency causes rickets

Question 25

Rickets

Answer 25

Caused by vitamin D deficiency

Question 26

Vitamin E

Answer 26

aka tocopherols, act as biological antioxidants, their aromatic rings destroy free radicals, preventing oxidative damage

Question 27

Vitamin K

Answer 27

aka phylloquinone or menaquinones, important for formation of prothrombin (a clotting factor), performs post translational modifications on a number of proteins, creating calcium binding sites

Question 28

Triacylglycerols

Answer 28

aka triglycerides, the preferred method of storying energy for long term use, contain one glycerol attached to three fatty acids by ester bonds, fatty acids usually vary, the carbon atom in lipids are more reduced than carbohydrates, giving two as much energy per gram during oxidation, very hydrophobic so they are not hydrated by body water and do not carry additional water weight, many stored in adipocytes

Question 29

Adipocytes

Answer 29

Animal cells specifically used for storage of large triacylgylcerol deposits

Question 30

Free fatty acids

Answer 30

Unesterified fatty acids that can travel in the bloodstream

Question 31

Soaps

Answer 31

Salts and free fatty acids that can be synthesized in saponification, act as surfactants forming micelles

Question 32

Saponification

Answer 32

Ester hydrolysis of triacylgylcerols using a strong base, like solid or potassium hydroxide

Question 33

Micelles

Answer 33

Can dissolve a lipid soluble molecule in its fatty acid core and then wash it away with water because of its shell of carboxylate head groups