Name: ……………………………………

Name: ……………………… Group: ………. Date: …………… STEROIDS, PROSTAGLANDINS AND TERPENS
Topics to prepare for the classes: 1. Structure, classification and biological functions of terpens and terpenoids. p. 1177- 2. Structure and biological functions of steroids. p. 1173-1176 3. Structure and biological functions of prostaglandins. p. 1176 - 1177 Problem 1
………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… 2. Draw structures and describe briefly biochemical importance/medical application of: Problem 2
Cholic acid, a major constituent of bile has the following structure: Cholic acid is secreted in bile as an amide linked to the amino group of glycine. The cholic acid-amino acid combination acts as ann amulsifying agent to disperse lipids in the intenstines for easier digestion. Draw the structure of cholic acid-glycine combination. Problem 3
Describe structure and biochemical application of prostaglandins. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… Problem 4
Give definition and classification and terpens. Problem 5
Draw synthetic stages of the squalene synthesis. How many isoprene units it contains. Problem 6
What are carotenes? What is their function and occurrence in nature? ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ……………………………………………………………………………………. Problem 7
Draw structure and describe biological functions of: a/ cholesterol; what do bad and good cholesterols mean? Preparation of licopene and -karotene from carrot Reagents:
Procedure:
Mix 10 g of finely cut carrot and 15 ml of ethanol in a 100 ml round-bottomed flask. Protect the flask against light with aluminium foil. Heat the mixture with the condenser for 5 minutes. Filtrate hot mixture with Büchner funnel and pour yellow filtrate to 100 ml Erlenmayer flask, also protected with aluminium foil. The solid from the funnel should be returned to the round- bottom flask, mixed wih10 ml of methylene chloride and heated in boiling for 5 minutes. The hot mixture should be again filtrated and the filtrate should be added to Erlenmayer flask with ethanol filtrate. The procedure with methylene chloride should be repeated three times. Pour the total content of Erlenmayer flask to a separatory funnel, add 10 ml of water and 15 ml of saturated solution of sodium chloride. Separate the bottom layer to dry Erlenmayer flask, add MgSO4 to dry and carefully evaporate the solvent. Draw the structures of your products and describe your observations and conclusions. Preparation of R-(+)-limonene from orange Reagents:
Procedure:
1. Perform steam distillation of the mixture of finely cut orange peel and 150 ml of 2. When you obtain 80 ml of distillate extract it three times with 15 ml of methylene 3. Add MgSO4 to methlyene extract to dry and then evaporate solvent on vacuum Draw the structure of your product and write observations and conclusions. TEST YOURSELF !!!
Choose the right answers. Remember that one or more answers can be correct. 1. Steroids are:
A. cortisol; B. testosterone; C. insulin; D. cholesterol; E. karotene; 2. Steroids have:
A. two-ring structure; B. three-ring structure C. four-ring structure; D. five-ring structure; E. none of them. 3. Choose the true statements:
A. prostaglandins arise from unsaturated carboxylic acids such as arachidonic B. mammals cannot biosynthesize arachidonic acid directly; C. mammals obtain linoleic acid from vegetable oils in their diet and extend the carbon chain of linoleic acid from 18 to 20 carbons while introducing two more double bonds.; D. linoleic acid is said to be an essential fatty acid, forming part of the dietary E. animals fed on diets that are deficient in linoleic acid grow poorly and suffer a number of other disorders, some of which are reversed on feeding them vegetable oils rich in linoleic acid and other polyunsaturated fatty acids.
4. Choose the true statements:
A. arachidonic acid is the biosynthetic precursor to PGE2; B. the structures of PGE1 and PGE2 are identical except that PGE2 has one more C. physiological responses to prostaglandins encompass a variety of effects: some prostaglandins relax bronchial muscle, others contract it, some stimulate uterine contractions and have been used to induce therapeutic abortions; D. PGE1 dilates blood vessels and increases blood pressure; E. PGE1 inhibits the aggregation of platelets and offers promise as a drug to 5. Choose the true statements:
A. the long-standing question of the mode of action of aspirin has been addressed in terms of its effects on prostaglandin biosynthesis; B. prostaglandin biosynthesis is the body’s response to tissue damage and is manifested by pain and inflammation at the affected site; C. aspirin has been shown to promote the activity of an enzyme required D. aspirin reduces pain and inflammation—and probably fever as well — by reducing prostaglandin levels in the body; 6. Choose the true statements:
A. much of the fundamental work on prostaglandins and related compounds was carried out by Sune Bergström and Bengt Samuelsson of the Karolinska Institute (Sweden)and by Sir John Vane of the Wellcome Foundation (Great Britain); B. these three shared the Nobel Prize for chemistry in 1982; C. prostaglandin research has now revealed that other derivatives of oxidized polyunsaturated fatty acids, structurally distinct from the prostaglandins, are also physiologically important; D. these fatty acid derivatives include, for example, a group of substances known E. leukotrienes have been implicated as mediators in immunological processes.
7. Choose the true statements:
A. the word “essential” as applied to naturally occurring organic substances can B. as used with respect to fatty acids, essential means “unnecessary”; C. “essential” is also used as the adjective form of the noun “essence”; D. the mixtures of substances that make up the fragrant material of plants are called essential oils because they contain the essence, that is, the odor, of the plant; E. very often, the principal volatile component of an essential oil belongs to a class of chemical substances called the terpenes.
8. Choose the true statements:
A. a steroid very closely related structurally to cholesterol is its 7-dehydro B. 7-dehydrocholesterol is formed by enzymic oxidation of cholesterol and has a C. 7-dehydrocholesterol is present in the tissues of the skin, where it is transformed to vitamin D3 by a sunlight-induced photochemical reaction; D. vitamin D3 is a key compound in the process by which Ca2+ is absorbed from E. high levels of vitamin D3 lead to Ca2+ concentrations in the body that are insufficient to support proper bone growth, resulting in the bone disease called rickets. 9. Choose the true statements:
A. cholesterol is biosynthesized in the liver, transported throughout the body to be used in a variety of ways, and returned to the liver where it serves as the biosynthetic precursor to other steroids; B. cholesterol is soluble in water; C. cholesterol is carried through the blood and tissues as part of a lipoprotein; D. the proteins that carry cholesterol from the liver are called low-density E. those that return it to the liver are the high-density lipoproteins, or HDLs.

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