Õèìèÿ: Íóêëå¿íîâ³ êèñëîòè, Ðåôåðàò

  • Êàòåãîðèÿ: Õèìèÿ
  • Òèï: Ðåôåðàò

«Íóêëå¿íîâ³ êèñëîòè»

Ïëàí

1. Çàãàëüíà õàðàêòåðèñòèêà ³ ñêëàä íóêëåîïðîòå¿ä³â.

2. Ñòðóêòóðí³ åëåìåíòè íóêëå¿íîâèõ êèñëîò:

à). íóêëåîçèä;

á). íóêëåîòèä;

â). íóêëå¿íîâà êèñëîòà.

3. Êëàñèô³êàö³ÿ ³ áóäîâà íóêëå¿íîâèõ êèñëîò.

4. Á³îëîã³÷íà ðîëü íóêëå¿íîâèõ êèñëîò.

Íà îñîáëèâó óâàãó, çàâäÿêè âèêîíóâàíèì ôóíêö³ÿì, çàñëóãîâóþòü ñêëàäí³ á³ëêè – íóêëåîïðîòå¿äè.

Íóêëåîïðîòå¿äè ì³ñòÿòüñÿ â êîæí³é êë³òèí³ æèâîãî îðãàí³çìó, âõîäÿ÷è äî ñêëàäó êë³òèííèõ ÿäåð, ñóáêë³òèííèõ ñòðóêòóð.

Íóêëå¿íîâ³ êèñëîòè áóëè â³äêðèò³ øâåéöàðñüêèì â÷åíèì ̳øåðîì ².Ô. ³ç ÿäåð êë³òèí ãíîþ ó âèãëÿä³ á³ëêîâî¿ ñïîëóêè íóêëå¿íó.

Âèâ÷àþ÷è áóäîâó áóëî âñòàíîâëåíî, ùî ïðè ã³äðîë³ç³ íóêëåîïðîòå¿äè ðîçïàäà-þòüñÿ íà á³ëêîâèé êîìïîíåíò òà íóêëå¿íîâ³ êèñëîòè.

Íóêëåîïðîòå¿äè – ñêëàäí³ á³ëêè ïðîñòåòè÷íîþ ãðóïîþ ÿêèõ º íóêëå¿íîâ³ êèñëîòè. Á³ëêîâèé òà ïðîñòåòè÷íèé êîìïîíåíòè çâ‘ÿçàí³ ì³æ ñîáîþ çà äîïîìî-ãîþ åëåêòðîñòàòè÷íèõ, âîäíåâèõ ³ êîîðäèíàö³éíèõ çâ‘ÿçê³â.

 çàëåæíîñò³ â³ä áóäîâè ïðîñòåòè÷íî¿ ãðóïè, íóêëåîïðîòå¿äè ïîä³ëÿþòü íà :

äåçîêñèðèáîíóêëåîïðîòå¿äè – ïðîñòåòè÷íà ãðóïà ÿêèõ ÄÍÊ;

ðèáîíóêëåîïðîòå¿äè – ïðîñòåòè÷íîþ ãðóïîþ ÿêèõ º ÐÍÊ.

ßâëÿþ÷èñü ïðîñòåòè÷íèìè ãðóïàìè íóêëåîïðîòå¿í³â ñàìå íóêëå¿íîâ³ êèñëîòè çáåð³ãàþòü (ÄÍÊ) ³ ïåðåäàþòü (ÐÍÊ) ñïàäêîâó ³íôîðìàö³þ.

Íóêëå¿íîâ³ êèñëîòè – âèñîêîìîëåêóëÿðí³ îðãàí³÷í³ ñïîëóêè ÿê³ ïîáóäîâàí³ ç âåëèêî¿ ê³ëüêîñò³ ìîíîíóêëåîòèä³â. Ïðè ã³äðîë³ç³ ðîçêëàäàþòüñÿ äî àçîòèñòèõ îñíîâ, ïåíòîç ³ ôîñôîðíî¿ êèñëîòè.

 ã³äðîë³çàò³ íóêëå¿íîâèõ êèñëîò áóëî çíàéäåíî 5 àçîòèñòèõ îñíîâ, äâ³ ç íèõ, àäåí³í ³ ãóàí³í – ïîõ³äí³ ãåòåðîöèêë³÷íî¿ ñïîëóêè ïóðèíó òîìó ¿õ íàçèâàþòü ïóðèíîâèìè àçîòèñòèìè îñíîâàìè:

                                                           NH2                        OH

 N                          N         N                    N        N                 N        

                                                                                                                  

                       N      NH                     N     NH    H2N      N      NH           

                      ïóðèí                         àäåí³í                         ãóàí³í          

                                                  (6–àì³íîïóðèí)           (2–àì³íî–6–îêñèïóðèí)

²íø³ òðè – ïîõ³äí³ øåñòè÷ëåííîãî ãåòåðîöèêëó ï³ðèì³äèíó, òîìó ¿õ íàçèâàþòü ï³ðèì³äèíîâèìè îñíîâàìè (óðàöèë, òèì³í, öèòîçèí):

                                     OH                    OH                           NH2

                                                                       CH3                                              

     N                     N                        N                              N                       

                                                                                                                  

   N     HO                   N        HO         N               HO          N      

     ï³ðèì³äèí           óðàöèë               òèì³í                           öèòîçèí     

Óðàöèë çà ñèñòåìàòè÷íîþ íîìåíêëàòóðîþ ìຠíàçâó – (2,4-äèîêñ³ï³ðèì³äèí), òèì³í – (5-ìåòèë-2,4-äèîêñ³ï³ðèì³äèí), öèòîçèí – (2– îêñ³–4–àì³íîï³ðèì³äèí).

Êð³ì àçîòèñòèõ îñíîâ â ã³äðîë³çàò³ òàêîæ çíàéøëè çàëèøêè ïåíòîç, à ñàìå ðèáîçè ³ äåçîêñèðèáîçè ó âèãëÿä³ –àíîìåð³â:

HOCH2           O           OH                                      HOCH2   O         OH

                   H       H                                                              H      H          

              H                      H                                             H                   H            

                 OH          OH                                                 HO              H               

          –ðèáîôóðàíîçà                                                –äåçîêñèðèáîôóðàíîçà     

Ïîð³âíþþ÷è ÿê³ñíèé ³ ê³ëüê³ñíèé ñêëàä ã³äðîë³çàò³â íóêëå¿íîâèõ êèñëîò, â÷åí³ ïîì³òèëè äåÿê³ â³äì³ííîñò³:

I–é òèï ã³äðîë³çàò³â                                   II–é òèï ã³äðîë³çàò³â

Äåçîêñèðèáîçà                                          Ðèáîçà

àäåí³í                                                         àäåí³í

ãóàí³í                                                         ãóàí³í

öèòîçèí                                                      öèòîçèí

ôîñôîðíà êèñëîòà                                     ôîñôîðíà êèñîòà

òèì³í                                                          óðàöèë

I–é òèï ã³äðîë³çàò³â ì³ñòèòü âóãëåâîä äåçîêñèðèáîçó, òîìó ö³ëèé ðÿä íóêëå¿íîâèõ êèñëîò ùî ìàþòü ã³äðîë³çàò òàêîãî òèïó áóëî íàçâàíî äåçîêñèðèáîíóêëå¿íîâè-ìè (ÄÍÊ).

II–é òèï ã³äðîë³çàò³â ì³ñòèòü âóãëåâîäíåâèé êîìïîíåíò ðèáîçó, òîìó íóêëå¿íîâ³ êèñëîòè ùî éîãî ì³ñòÿòü íàçèâàþòü ðèáîíóêëå¿íîâèìè (ÐÍÊ) êèñëîòàìè.

Ñòðóêòóðíîþ ÷àñòèíîþ íóêëå¿íîâî¿ êèñëîòè º íóêëåîòèä äî ñêëàäó ÿêîãî âõîäÿòü àçîòèñòà îñíîâà, âóãëåâîä ³ ôîñôîðíà êèñëîòà.

 ðåçóëüòàò³ âçàºìî䳿 ã³äðîêñèëó âóãëåâîäó (ðèáîçè ÷è äåçîêñèðèáîçè) ÿêèé çíàõîäèòüñÿ á³ëÿ ïåðøîãî àòîìà âóãëåöþ ç àòîìîì âîäíþ á³ëÿ 9-ãî àòîìà àçîòó àçîòèñòî¿ îñíîâè ç óòâîðåííÿì íîâîãî çâ‘ÿçêó N–H ( â ðåçóëüòàò³ â³äùåïëåííÿ ìîëåêóëè âîäè), óòâîðþºòüñÿ íóêëåîçèä.


                                                           NH2                                                          

                                                    N                 N                                                 

                                                                                                                           

                                                            N     N                                                      

                                                                   H                                                      

                                                                                                                            

        HOCH2      O                 OH                                                                       

                   H       H                                                                                   

              H                      H                                                                         

                 OH          OH                                                                             

                                                           NH2                                                          

                                                    N                 N                                                 

                                                                                                                           

                                                            N     N                                                      

                                                                                      + H2O                           

                                                                                                                            

        HOCH2      O                                                                                              

                   H       H                          Íóêëåîçèä – àäåíîçèí                             

              H                      H                                                                                   

                 OH          OH                                                                                      

ßêùî â óòâîðåíí³ íóêëåíîçèäó áåðå ó÷àñòü àçîòèñòà îñíîâà ãóàí³í, òî íóêëåîçèä áóäå ìàòè íàçâó – ãóàíîçèí; ÿêùî óðàöèë – óðèäèí; öèòîçèí – öèòèäèí; òèì³í – òèì³äèí.

 ðåçóëüòàò³ ïðèºäíàííÿ ôîñôîðíî¿ êèñëîòè äî 5–¿ ã³äðîêñèëüíî¿ ãðóïè ïåíòîçè â ñêëàä³ íóêëåîçèäó çà ðàõóíîê ñêëàäíîåô³ðíîãî çâ‘ÿçêó, óòâîðþºòüñÿ ñòðóêòóð-íà ÷àñòèíà íóêëå¿íîâî¿ êèñëîòè – íóêëåîòèä.


                                                           NH2                                                          

                                                    N                 N                                                 

                                                                                                                           

                     OH                                 N     N                                                      

          HO–P=O                                                                                                   

+                    OH                                                                                                

        HOCH2      O                                                                                              

                   H       H                                                                                            

              H                      H                                                                                   

                 OH          OH                                                                                      

                                                           NH2                                                          

                                                    N                 N                                                 

                                                                                                                           

OH                                                      N     N                                            

O=P                                                                                                           

OH    O                                                                                    + H2O                 

             CH2      O                                                                                                

                   H       H                Íóêëåîòèä – àäåí³ëîâà êèñëîòà.                     

              H                      H                                                                                   

                 OH          OH                                                                                      

ßêáè â óòâîðåíí³ íóêëåîòèäó áðàâ ó÷àñòü íóêëåîçèä ãóàíîçèí, òî íàçâà íóêëåî-òèäó áóëà á â³äïîâ³äíî – ãóàí³ëîâà êèñëîòà; óðèäèí – óðèäèëîâà êèñëîòà; öèòèäèí – öèòèäèíîâà êèñëîòà; òèì³äèí – òèì³äèíîâà êèñëîòà.

Äî ñêëàäó ìîëåêóëè íóêëå¿íîâî¿ êèñëîòè ìîæå âõîäèòè â³ä 80 äî 1000000 íóêëåîòèäíèõ çàëèøê³â ÿê³ çâ‘ÿçóþòüñÿ ì³æ ñîáîþ çâ‘ÿçêàìè, ùî óòâîðþþòüñÿ â ðåçóëüòàò³ âçàºìî䳿 3-¿ ñïèðòîâî¿ ãðóïè ïåíòîçè îäíîãî íóêëåîòèäó òà ôîñôîð-íîãî ã³äðîêñèëó ùî çíàõîäèòüñÿ á³ëÿ 5-ãî àòîìà âóãëåöþ ïåíòîçè äðóãîãî íóêëåîòèäó, óòâîðþþ÷è ïðè öüîìó ìîëåêóëó íóêëå¿íîâî¿ êèñëîòè. Îñòàííÿ ÿâëÿºòüñÿ ïðîñòåòè÷íîþ ãðóïîþ íóêëåîïðîòå¿äó, á³ëêîâîþ ÷àñòèíîþ ÿêîãî íàé÷àñò³øå âèñòóïàþòü ïðîòàì³íè ³ ã³ñòîíè.

                                                           NH2                                                          

                                                    N                 N                                                 

                                                                                                                           

OH                                                      N     N                                                      

O=P                                                                                                                     

OH    O                                                       Íóêëåîòèä – àäåí³ëîâà êèñëîòà   

             CH2      O                                                                                                

                    H       H                                                                                            

              H                      H                                                                                   

                 OH         OH                                                                                      

                                                           OH                                                            

          +                                        N                 N                                                 

                                                                                                                           

OH                                          H2N     N     N                                                      

O=P                                                                                                                     

OH    O                                                                                                                

             CH2      O                                                                                                

                   H       H                Íóêëåîòèä – ãóàí³ëîâà êèñëîòà.                     

              H                      H                                                                                   

                 OH          OH                                      


                                                         NH2                                                            

                                                    N                 N                                                 

                                                                                                                           

OH                                                      N     N                                                      

O=P                                                                                                                     

OH    O                                                                                                                

             CH2      O                                                                                                

                   H       H                                                                                            

              H                      H                                                                                   

                                OH                                                                                      

                                                           OH                                                            

          Π                                      N                 N                                                 

                                                                                                                           

                                                H2N     N     N                + Í2Π                          

O=P                                                                                                                     

OH    O                                                                                                                

             CH2      O                                                                                                

                   H       H                          Äèíóêëåîòèä                                             

              H                      H                                                                                   

                 OH          OH                                                                                      

Îòæå: íóêëå¿íîâ³ êèñëîòè – ïðèðîäí³ á³îïîë³ìåðè ÿê³ ñêëàäàþòüñÿ ç äóæå âåëèêî¿ ê³ëüêîñò³ íóêëåîòèä³â (ìîíîìåð³â).

ÄÍÊ ³íñóë³íó ëþäèíè ñêëàäàºòüñÿ ç 2860 íóêëåîòèä³â;

ÄÍÊ ñîìàòîòðîï³íó – 15000 íóêëåîòèä³â;

ÄÍÊ ì³òîõîíäð³é – 30000 íóêëåîòèä³â.

Ïîñê³ëüêè íóêëå¿íîâ³ êèñëîòè º ñêëàäíèìè á³ëêàìè, òî äëÿ íèõ òàêîæ âëàñòèâèé âèñîêèé ð³âåíü îðãàí³çàö³¿.

ϳä ïåðâèííîþ ñòðóêòóðîþ  ðîçóì³þòü ïîðÿäîê ÷åðãóâàííÿ íóêëåîòèä³â ó ïîë³-íóêëåîòèäíèõ ëàíöþãàõ.

Äëÿ êîæíî¿ íóêëå¿íîâî¿ êèñëîòè õàðàêòåðíà ñâîÿ ïåðâèííà ñòðóêòóðà, ÿêà ³ âèçíà÷ຠâèäîâó ñïåöèô³÷í³ñòü æèâèõ îðãàí³çì³â.

 

Áóäîâà ÄÍÊ

Ïîñê³ëüêè ÄÍÊ – ñêëàäí³ á³ëêè íóêëåîïðîòå¿äè, òî âîíè õàðàêòåðèçóþòüñÿ âåëè-êèìè ìîëåêóëÿðíèìè ìàñàìè (100000–3000000) òà âåëèêîþ ê³ëüê³ñòþ ìîíî-íóêëåîòèä³â (80 – 100000).

Âñ³ ìîíîíóêëåîòèäè ÿê³ñíî ïðåäñòàâëåí³ 4-ìà ïðåäñòàâíèêàìè äî ñêëàäó ÿêèõ âõîäèòü äåçîêñèðèáîçà: äåçîêñèàäåí³ëîâà êèñëîòà (À), äåçîêñèãóàí³ëîâà êèñëîòà (Ã), äåçîêñèöèòèäèíîâà (Ö), äåçîêñèòèì³äèíîâà (Ò).

Çâ‘ÿçóþ÷èñü ì³æ ñîáîþ 3–5 ôîñôîåô³ðíèìè çâ‘ÿçêàìè âîíè óòâîðþþòü ïîë³-íóêëåîòèäíèé ëàíöþã ÄÍÊ.

Äîñë³äæóþ÷è áóäîâó ìîëåêóëè ÄÍÊ çà äîïîìîãîþ ðåíòãåíîñòðóêòóðíîãî, òà ³í-øèõ âèä³â àíàë³çó, áóëî âñòàíîâëåíî ùî:

1. Ìîëåêóëà ÄÍÊ ñêëàäàºòüñÿ ç äâîõ àíòèïàðàëåëüíèõ ëàíöþã³â.

2. Àçîòèñò³ îñíîâè îáîõ ïîë³ïåïòèäíèõ ëàíöþã³â çíàõîäÿòüñÿ â ñåðåäèí³ óÿâíîãî ïðîñòîðîâîãî öèë³íäðó, ïåíòîçè òà çàëèøêè ôîñôîðíî¿ êèñëîòè – ççîâí³.

3. Àçîòèñò³ îñíîâè ïîë³ïåïòèäíèõ ëàíöþã³â ðîçì³ùåí³ ïî ïðèíöèïó êîìïëåìåí-òàðíîñò³ (âçàºìîäîïîâíåííÿ). Öÿ çàêîíîì³ðí³ñòü â³äîìà ï³ä íàçâîþ ïðàâèëà ×àðãàôôà.


Ïðàâèëî ×àðãàôôà

3.1.Ïóðèíîâ³ àçîòèñò³ îñíîâè îäíîãî ïîë³ïåïòèäíîãî ëàíöþãà ðîçì³ùóþòüñÿ ïðîòè ï³ðèì³äèíîâèõ îñíîâ äðóãîãî ïîë³ïåïòèäíîãî ëàíöþãà. Àäåí³í ïðîòè òèì³íó (ñòàá³ë³çóºòüñÿ äâîìà âîäíåâèìè çâ‘ÿçêàìè); ãóàí³í ïðîòè öèòîçèíó (ñòàá³ë³çóºòüñÿ òðüîìà âîäíåâèìè çâ‘ÿçêàìè).

 

Íàñë³äêè ïðàâèëà ×àðãàôôà

 ìîëåêóë³ ÄÍÊ ñóìà ïóðèíîâèõ îñíîâ ð³âíà ñóì³ ï³ðèì³äèíîâèõ: À+Ã=Ò+Ö;

=1

ʳëüê³ñòü àäåí³íó äîð³âíþº ê³ëüêîñò³ òèì³íó (À=Ò), ãóàí³íó äîð³âíþº öèòîçèíó (Ã=Ö). Ñï³ââ³äíîøåííÿ ñóì ïàð À+Ò ³ Ã+Ö íîñèòü íàçâó êîåô³ö³ºíòà ñïåöè-ô³÷íîñò³ ³ º îäí³ºþ ç íàéâàæëèâ³øèõ õàðàêòåðèñòèê ÄÍÊ. Êîåô³ö³ºíò ñïåöèô³÷-íîñò³ áóâ â³äêðèòèé ó 1962 ðîö³ Á³ëîçåðñüêèì ³ Ñï³ðê³íèì ³ ñóòü éîãî ïîëÿãຠó ñë³äóþ÷îìó:

1) ßêùî   1, òî ìîëåêóëà ÄÍÊ –– ÀÒ–òèïó, õàðàêòåðíà äëÿ îðãàí³çì³â âèùèõ òâàðèí òà ðîñëèí.

2) ßêùî   1, òî ìîëåêóëà ÄÍÊ ––ÃÖ–òèïó, õàðàêòåðíà äëÿ ì³êðîîðãàí³çì³â.

Îòæå:1.Ìîëåêóëà ÄÍÊ âîëî䳺 ïåðâèííîþ, âòîðèííîþ, òðåòèííîþ ñòðóêòóðàìè.

2.ÄÍÊ– ëîêàë³çîâàíà â õðîìîñîìàõ êë³òèííèõ ÿäåð.

3.ÄÍÊ çâ‘ÿçàí³ ç á³ëêàìè îñíîâíîãî õàðàêòåðó – ã³ñòîíàìè.

4.ÄÍÊ çäàòí³ äî ñàìîâ³äòâîðåííÿ â ðåçóëüòàò³ ïðîöåñó ðåïë³êàö³¿.

5.ÄÍÊ–îñíîâíèé íîñ³é ³íôîðìàö³¿ ïðî áóäîâó ³ ñòðóêòóðó á³ëê³â îðãàí³çìó.

Áóäîâà ÐÍÊ

Ìr(ÐÍÊ)=10000–16000000. Ïîë³íóêëåîòèä ÐÍÊ ì³ñòèòü  2–3000000 ìîíîíóêëåî-òèä³â. Â÷åí³ âñòàíîâèëè ùî:

1. Äî ñêëàäó íóêëåîòèä³â ÐÍÊ âõîäèòü ðèáîçà.

2. Íóêëåîòèäè ÿê³ñíî ïðåäñòàâëåí³ àäåí³ëîâàîþ, ãóàí³ëîâîþ, öèòèäèíîâîþ òà óðàöèëîâîþ êèñëîòàìè.

3. Íóêëåîòèäè çâ‘ÿçàí³ ì³æ ñîáîþ 3–5 ôîñôîåô³ðíèìè çâ‘ÿçêàìè â îäíîëàíöþãî-âèé ïîë³ïåïòèäíèé ëàíöþã.

4. Ïîë³ïåïòèäíèé ëàíöþã ñï³ðàë³çîâàíèé ëèøå íà êîðîòêèõ ä³ëÿíêàõ.

5. Îñíîâíå ì³ñöå ëîêàë³çàö³¿ – âíóòð³êë³òèííèé ïðîñò³ð.

6. ʳëüê³ñòü ÐÍÊ ïîñò³éíî çì³íþºòüñÿ ³ çàëåæèòü â³ä ³íòåíñèâíîñò³ ïðîöåñ³â ñèíòåçó á³ëêà.

Çàëåæíî â³ä âèêîíóâàíèõ ôóíêö³é ìîëåêóëè ÐÍÊ ïîä³ëÿþòüñÿ íà :

Ìàòðè÷í³ ÐÍÊ (Ìr =25000–1000000) – ì³ñòÿòü â³ä 75 äî 3000 íóêëåîòèä³â. Ñòàíîâëÿòü 2 % â³ä çàãàëüíîãî âì³ñòó ÐÍÊ êë³òèíè. Âèñòóïàþòü ïîñåðåäíèêàìè ì³æ ìîëåêóëàìè ÄÍÊ  òà ÐÍÊ ðèáîñîì íà ÿêèõ â³äáóâàºòüñÿ á³îñèíòåç á³ëêà. Øâèäêî ñèíòåçóþòüñÿ ³ ðîçïàäàþòüñÿ.

Òðàíñïîðòí³ ÐÍÊ (Ìr=25000–31000) – ì³ñòÿòü 70–90 íóêëåîòèä³â. Ñòàíîâëÿòü 10 – 15 % âñ³õ ÐÍÊ êë³òèíè. Òðàíñïîðòóþòü àì³íîêèñëîòè äî ì³ñöÿ çáîðêè ìîëåêóëè á³ëêà.

Ðèáîñîìàëüí³ ÐÍÊ (Ìr= 500000–16000000) ì³ñòÿòü 1500–4500 íóêëåîòèä³â. Ñòàíîâëÿòü 80–90% âñ³õ ÐÍÊ êë³òèíè. ̳ñòÿòüñÿ â ðèáîñîìàõ (îðãàíî¿ä äå ïðî-õîäèòü á³îñèíòåç á³ëêà). ¯õ ðîëü äî ê³íöÿ íå ç‘ÿñîâàíà.

Îòæå: ìîëåêóëè ÄÍÊ º íîñ³ÿìè ³íôîðìàö³¿ ïðî áóäîâó ³ ñòðóêòóðó á³ëê³â; ìîëåêóëè ÐÍÊ ñïðèÿþòü òî÷íîìó çíÿòòþ ³íôîðìàö³¿ ç ÄÍÊ ³ â³äòâîðåíí³ ¿¿ â ìîëåêóë³ á³ëêà.

Ïèòàííÿ äëÿ ñàìîêîíòðîëþ.

1.Ñêëàä íóêëåîïðîòå¿ä³â ÄÍÊ.

2.Ñêëàä íóêëåîïðîòå¿ä³â ÐÍÊ.

3.Ïîíÿòòÿ íóêëåîçèäó ³ íóêëåîòèäó.

4.Êëàñèô³êàö³ÿ íóêëå¿íîâèõ êèñëîò.

5.Áóäîâà òà ð³âí³ îðãàí³çàö³¿ ÄÍÊ.

6.Áóäîâà òà ð³âí³ îðãàí³çàö³¿ ÐÍÊ.

7. Ïðàâèëà ×àðãàôôà, éîãî íàñë³äêè.

8. Ñóòü êîåô³ö³ºíòó ñïåöèô³÷íîñò³.

9. Âèäè ÐÍÊ òà ôóíêö³¿ ÿê³ âîíè âèêîíóþòü.


Åùå èç ðàçäåëà Õèìèÿ:


 Ýòî èíòåðåñíî
 Ðåêëàìà
 Ïîèñê ðåôåðàòîâ
 
 Àôîðèçì
 ïèâå — ñèëà, â âèíå — çäîðîâüå, â êîíüÿêå — áëàãîðîäñòâî, à â âîäå — ìèêðîáû...
 Ãîðîñêîï
Ãîðîñêîïû
 Ñ÷¸ò÷èêè
bigmir)net TOP 100