Figure 20-2 pulsed-field gel electrophoresis electrodes B ( B A返回 Copyright o 2004 Pearson Education, Inc, publishing as Benjamin Cummings
Figure 20-2 pulsed-field gel electrophoresis 返回
Electrophoresis separates DNA molecules according to their molecular weight shape topological properties (figure 6-26) It is used to separate RNAs RNAs have a uniform negative charge, but RNA usually single stranded and have extensive secondary and tertiary structure. to deal with this RNAs can be treated with reagents to prevent the formation of base pairs
Electrophoresis separates DNA molecules according to their molecular weight,shape topological properties. (figure 6-26) It is used to separate RNAs.RNAs have a uniform negative charge,but RNA usually singlestranded and have extensive secondary and tertiary structure.to deal with this ,RNAs can be treated with reagents to prenvent the formation of base pairs
Figure 6-26 schematic of electrophoretic separation of DNA topoisomers B C D Copyright 2004 Pearson Education. Inc.. publishing as Benjamin Cummings
Figure 6-26 schematic of electrophoretic separation of DNA topoisomers
1 2 Restriction Endonucleases cleave DNA Molecules at particular sites Restriction endonucleases, nucleases that cleave dNa at particular sites by the recognition of specific sequences. Restriction enzymes used in molecular biology typically recognize short(4-8bp)target sequences, usually palindromic, and cut at a defined position within those sequences
1.2 Restriction Endonucleases Cleave DNA Molecules at Particular Sites Restriction endonucleases:nucleases that cleave DNA at particular sites by the recognition of specific sequences. Restriction enzymes used in molecular biology typically recognize short(4-8bp) target sequences,usually palindromic,and cut at a defined position within those suquences
Example ECoR1 recognizes and cleaves the sequence 5 GAATTC-3 (figure 20-3) Sau3al recognizes an octameric sequence5 GCGGCCGC-3 and cut (table 20-1)
Example: EcoR1 recognizes and cleaves the sequence 5’- GAATTC-3’(figure 20-3) Sau3A1 recognizes an octameric sequence5’- GCGGCCGC-3’ and cut.(table 20-1)