Available online
Description
The programme presented by Dr. Norman Cohen of the Open University is about the mechanisms of genetic control in bacteria and the techniques used to study these. The isolation of a nutritional muta...nt by replica plating is described, and the theoretical background to the PaJaMo experiment - the experiment which proved the existence of a repressor substance. The results of this crucial experiment are discussed.;Time-lapse shots of a developing frog embryo. Shots show the embryo at various stages of development from cleavage of a two cell egg to the tadpole stage. Commentary by Norman Cohen explains what is happening. Cohen discusses the problem of finding a suitable organism for cell differentiation experiments. He looks at several organisms in turn and lists their advantages and disadvantages. Shot of two frogs in a tank. Shot of a carrot. Shot of dtosophila in a bottle. Shot of several flasks of bacteria in liquid medium. Cohen picks up one flask. He explains why this is the best organism for experimental purposes. Cohen demonstrates and explains how bacterial specimen from the flask are prepared for laboratory experiments. Cohen demonstrates method for diluting bacterial culture. Cohen spreads sample of the diluted culture on an agar dish, then shows colonies on agar dishes which have been similarly treated. Cohen shows an agar dish on which foreign cultures have also established themselves. Cohen demonstrates and discusses a method for isolating lactose-minus mutant bacteria for genetic study. (Isolation of nutritional mutant by replica planting) Cohen uses a mag. board diagram to explain the theoretical background to the Pa Ja Mo experiment which proved the existence of a repressor substance. Cohen discusses the results. Cohen demonstrates some techniques which students will have to perform as part of their home experiments. Cohen demonstrates a technique for placing bacteria cultures into a liquid solution from an agar medium. Cohen shows how sterile agar petri dishes are prepared. Cohen shows a method for placing liquid bacteria suspension on a sterile agar petri dish. He then shows how a slime mold spore suspension is produced and how this is placed on a bacterial culture in a petridish. The results - effect of spores on bacteria - are seen after several hours of incubation. Cohen shows some petri dishes which have become contaminated with foreign organisms. He explains what students should do with contaminated dishes.
The programme presented by Dr. Norman Cohen of the Open University is about the mechanisms of genetic control in bacteria and the techniques used to study these. The isolation of a nutritional muta...nt by replica plating is described, and the theoretical background to the PaJaMo experiment - the experiment which proved the existence of a repressor substance. The results of this crucial experiment are discussed.;Time-lapse shots of a developing frog embryo. Shots show the embryo at various stages of development from cleavage of a two cell egg to the tadpole stage. Commentary by Norman Cohen explains what is happening. Cohen discusses the problem of finding a suitable organism for cell differentiation experiments. He looks at several organisms in turn and lists their advantages and disadvantages. Shot of two frogs in a tank. Shot of a carrot. Shot of dtosophila in a bottle. Shot of several flasks of bacteria in liquid medium. Cohen picks up one flask. He explains why this is the best organism for experimental purposes. Cohen demonstrates and explains how bacterial specimen from the flask are prepared for laboratory experiments. Cohen demonstrates method for diluting bacterial culture. Cohen spreads sample of the diluted culture on an agar dish, then shows colonies on agar dishes which have been similarly treated. Cohen shows an agar dish on which foreign cultures have also established themselves. Cohen demonstrates and discusses a method for isolating lactose-minus mutant bacteria for genetic study. (Isolation of nutritional mutant by replica planting) Cohen uses a mag. board diagram to explain the theoretical background to the Pa Ja Mo experiment which proved the existence of a repressor substance. Cohen discusses the results. Cohen demonstrates some techniques which students will have to perform as part of their home experiments. Cohen demonstrates a technique for placing bacteria cultures into a liquid solution from an agar medium. Cohen shows how sterile agar petri dishes are prepared. Cohen shows a method for placing liquid bacteria suspension on a sterile agar petri dish. He then shows how a slime mold spore suspension is produced and how this is placed on a bacterial culture in a petridish. The results - effect of spores on bacteria - are seen after several hours of incubation. Cohen shows some petri dishes which have become contaminated with foreign organisms. He explains what students should do with contaminated dishes.
| Item code: | S2-5; 02 |
|---|---|
| First transmission date: | 05-08-1973 |
| Published: | 1973 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:24 |
| + Show more... | |
| Producer: | Jim Stevenson |
| Contributor: | Norman Cohen |
| Publisher: | BBC Open University |
| Keyword(s): | Bacteria; Genetic control; Isolation; Mechanisms; Nutritional mutant; PaJaMo experiment; Replica plating; Repressor substance; Techniques |
| Master spool number: | 6HT/70929 |
| Production number: | 00525_1020 |
| Videofinder number: | 2822 |
| Available to public: | no |
