On the DAT outline it says that there can be laboratory technique questions. Does anyone know what theses questions are like? Any examples? How can you study for them?
laboratory technique questions
- Thread starter Ital91
- Start date
I was just looking at a problem on a practice test about electrophoresis of an amino acid... and I looked up the answer ( I think someone asked a question about this in an earlier post)
So I guess this would probably be worth knowing... this is taken from http://chimge.unil.ch/En/ph/1ph81.htm . It has some useful stuff on there.
Each amino acid has a specific isoelectric pH (pHi the pH at which amino acids are electrically neutral). At pH differing from pHi, amino acids bear an overall charge and therefore migrate under the effect of an electric field. Thus, working at a fixed pH (buffered solution) allows one to separate various amino acids by electrophoresis.
When an amino acid is placed in an electric field, it migrates towards the electrode of opposed polarity, while the neutral (zwitterionic) molecules do not migrate. Therefore :
When pH > pHi the amino acid bears a negative total charge: it migrates towards the positive electrode (anode).
When pH < pHi the amino acid bears a positive total charge: it migrates towards the negative electrode (cathode).
When pH = pHi the amino acid is in its zwitterionic, neutral form: it does not migrate and remains at the starting point.
So I guess this would probably be worth knowing... this is taken from http://chimge.unil.ch/En/ph/1ph81.htm . It has some useful stuff on there.
Each amino acid has a specific isoelectric pH (pHi the pH at which amino acids are electrically neutral). At pH differing from pHi, amino acids bear an overall charge and therefore migrate under the effect of an electric field. Thus, working at a fixed pH (buffered solution) allows one to separate various amino acids by electrophoresis.
When an amino acid is placed in an electric field, it migrates towards the electrode of opposed polarity, while the neutral (zwitterionic) molecules do not migrate. Therefore :
When pH > pHi the amino acid bears a negative total charge: it migrates towards the positive electrode (anode).
When pH < pHi the amino acid bears a positive total charge: it migrates towards the negative electrode (cathode).
When pH = pHi the amino acid is in its zwitterionic, neutral form: it does not migrate and remains at the starting point.
- Joined
- Dec 11, 2004
- Messages
- 11,417
- Reaction score
- 147
You may see questions involving how to mix up solutions (cv = cv equations) too.
