Chapter 5: Lipid Structure and Function

Question 1

amphipathic

Answer 1

both an hydrophobic and hydrophilic regions

Question 2

phospholpids

Answer 2

phosphate and alcohol that compreise the polar head, joined to a hydrophobic fatty acid by phosphodiester linkages.

Question 3

glycerol

Answer 3

3 carbon alcohol

Question 4

Unsaturated fatty acid.

Answer 4

Includes one or more double bonds. Double bonds introduce kinks to the fatty acid chain, which makes it difficult for them to stack and solidify. Therefore they tend to be liquids at room temperature.

Question 4

Sphingolipids.

Answer 4

The ABO blood typing system is based on cell surface antigen on red blood cells. They are the sites of biological recognition of the cell surface and can be bonded to various heads, groups and fatty acids. Sphingolipids have sphingosine or sphingoid backbone as opposed to glycerol backbone of glycerophospholipids. Any lipid linked to sugar can be termed glycolipid. The simplest sphingolipid is ceramide, which has a single hydrogen atom as its head group. Sphingomyelins are major class of sphingolipids, they are also phospholipids. They are a major component in the plasma membrane of cells producing myelin, the insulating sheet for axons. Glycosphingolipids These have heads group composed of sugar bonded by glycolytic linkages. They have found mainly on the outer surface of the plasma main brain and can be further classified as cerebrosides, which have a single sugar, or globosides which have two or more sugars. Gangliosides are the most complex sphingolipids. They are glycolipids that have polar head groups composed of oligosaccharides with one more N-acetylneuraminic acid (NANA).

Question 5

Fully saturated fatty acid.

Answer 5

Will have only single bonds. The carbon atom is considered saturated when it is bonded to four other atoms with no Pi bonds.

Question 6

Waxes

Answer 6

Are esters of long chain fatty acids with long chain alcohols. They function as protection for both plants and animals. In plants, waxes are secreted as a surface coating to prevent excessive evaporation into protect against parasites. In animals, waxes are secreted to prevent dehydration, as a water repellent, to keep skin and feathers dry, and as a lubricant.

Question 6

Glycerophospholipids.

Answer 6

Specifically, those fearful lipids that contain a glycerol backbone bounded by Ester linkages to two fatty acids and by a phosphodiester linkage to a highly polar head group. The membrane surface properties of these molecules make them very important to cell recognition, signaling and binding. Two examples are phosphatidylcholine and phosphatidylethanolamine.

Question 7

Glycolipid.

Answer 7

Any lipid linked to sugar.

Question 8

Terpenes

Answer 8

They are a difference chemical that are metabolic precursors to steroids and other lipid signaling molecules and have varied independent functions. Terpenes are all classes of lipids built from isoprene (C5H8) moieties. They are the primary components of much more pleasant smelling essential oils and pungent chemicals that are part of plants and insects protective mechanism. A single terpene unit contains 2 isoprene units, they are called monoterpenes. Sesquiterpenes contains 3 isoprene units. Diterpenes contain 4. Carotenoids are tetraterpenes and have eight isoprene units.

Question 9

Terpenoids

Answer 9

They are sometimes referred to as isoprenoids, or derivatives of terpenes that have undergone oxygenation or rearrangement of the carbon skeleton.

Question 10

Steroids.

Answer 10

Metabolic derivatives of terpenes. They are characterized by having four cycloalkane rings fused together, 3 cyclohexane and one cyclopentane. Steroid functionality is determined by the oxidation status of these rings as well as functional groups they carry. They are nonpolar. Steroid hormones are steroids that act as hormones, meaning that they are secreted by endocrine glands into the bloodstream and then travel on protein carriers to distant sites where they can bind to specific high affinity receptors and alter gene expression levels.

Question 10

Prostaglandins.

Answer 10

This 20 carbon molecules are unsaturated carboxylic acid derived from arachidonic acid and contained 5-carbon ring. They can act as powder, clean or outdoor green signaling molecules. Regulator synthesis of cyclic adenosine monophosphate (cAMP) which is intracellular messenger. He has powerful effects on smooth muscle function, influence over the sleep wake cycle and the elevation of body temperature associated with fever and pain. Non steroidal anti-inflammatory drugs like aspirin inhibit the enzyme cyclooxygenase which aids in the production of prostaglandins.

Question 11

Cholesterol.

Answer 11

It is a steroid that is responsible for mediating membrane fluidity. It is amphipathic molecule containing both hydrophilic and hydrophobic components. He maintains relatively constant fluidity in cell membranes. At low temperature, it keeps the cell membrane from solidifying, and at high temperatures it holds the membrane intact and prevents it from becoming too permeable. Accumulation of Cholesterol in arterial walls results in as atherosclerosis., a hardening of the walls.

Question 12

Vitamin A.

Answer 12

It is also called carotene is an unsaturated hydrocarbon that is important in vision, growth and development, and immune function. Derives retinol which is a component of light sensing molecular system in human eye. Retinol, the storage form of vitamin A is also oxidized to retinoic acid, a hormone that regulates gene expression during epithelial development.

Question 13

Fat soluble vitamins.

Answer 13

There are a sensual nutrient that must be consumed in the diet. These vitamins include A, D, E & K.

Question 14

Vitamin D.

Answer 14

It is also called chloricalciferol. It can be consumed from the UV light driven reaction in the skin. In the liver and kidneys, vitamin D is converted to calcitriol, the biological active form of vitamin D. Calcitriol increases calcium and phosphate uptake in the intestines, which promote bone production. A lack of vitamin D can result in rickets, a condition seen in children and characterized by underdevelopment.

Question 15

Vitamin K.

Answer 15

It’s actually a group of compounds including phylloquinone and menaquinones. Important in clotting factor in the blood. The aromatic ring of vitamin K undergoes a cycle of oxidation and reduction during the formation of prothrombin. Vitamin K is also required to induce calcium binding sites on several calcium dependent proteins.

Question 15

Vitamin E.

Answer 15

Characterizes a group of closely related lipid called tocopherols and tocotrienols. These are characterized by a substituted aromatic ring with the long isoprenoid side chain and are characteristically hydrophobic. It prevents oxidative damage and important contribute to the development of cancer and aging.

Question 16

Triglycerides.

Answer 16

Also called triacylglycerols. They are composed of three fatty acid bonded by Ester linkages to glycerol. These compounds are nonpolar and hydrophobic. Special sales in animals known as adipocytes store large amount of fat and are found primarily under the skin, around mammary glands and in the binominal cavity. They are used for energy storage because the carbon atoms of fatty acids are more reduced than those of sugars, which contain numerous alcohol groups. The result of this is that the oxidation of triglycerides yield twice the amount of energy per gram as carbohydrates. Making this a far more energy dense storage mechanism compared to polysaccharides like glycogen. They’re also hydrophobic, which decreases their weight.

Question 17

Saponification.

Answer 17

Is the Esther hydrolysis of triglycerides using a strong base. Traditionally, the base uses LYE, the common name for sodium or potassium hydroxide. The result is the basic cleavage of the fatty acid, leaving the sodium salt of the fatty acid and glycerol. The fatty acid salt is what we known as soap.

Question 18

Soap

Answer 18

Can act as a surfactant. A surfactant lowers the surface tension at the surface of a liquid, serving as a detergent or emulsifier. He creates a myth cell which are tiny aggregates of soap with the hydrophobic tails turned inward and the hydrophilic heads turned outwards, thereby shielding the hydrophobic lipid tails and allowing for overall solvation.

Question 19

What is SOAP?

Answer 19

The fatty acid salt.