1.1 Laboratory techniques for Biologists Flashcards
Unit 1: Cells and Proteins
What hazards may be encounted in the lab?
-Toxic chemicals
-Corrosive chemicals
-Heat and flammable substances
-Pathogenic organisms
-Mechanical equipment
What is a risk?
A risk is the like hood of harm arising from any given hazard, and risk levels can range in severity from low to high
What are some possible control measures?
-appropriate handling and disposal techniques
-protective clothing and equipment
-aseptic techniques in microbiology
What are Log Serial Dilutions?
These are dilutions that differ by constant proportion
What are Linear Dilutions
Dilutions differ by an equal interval , all make up the same volume
What is Colorimetry used to find out?
It can be used to estimate the concentration of a known solute
What can Colorimetry also be used?
The density of cells in a culture and the turbidity of a liquid
How can a standard curve be used in the lab?
Take unknown concentration, find its absorption and compare it to standard curve
What is a buffer?
A buffer is a solution where adding acids or alkalis have very small effects on the pH. This allows pH in a reaction mixture to be kept constant
What does a centrifugation used for?
This is used to separate molecules based on density
How does a centrifugation work?
It involves spinning samples and very high speeds and this causes the more dense to accumulate at the bottom
What does Chromatography: Paper and thin layer seperate?
Amino acids and sugars
How does Chromatography PATL work?
It works by placing the solute at the bottom of the chromatogram depends on its solubility. More soluble molecules travel quicker and end up at the top
What is the differences between the paper and thin layer?
Paper chromatography uses cellulose based paper and thin layer chronography involved the use of silcaged or solid cellulose instead
What does Affinity Chromatography?
Separates one specific protein from a mixture and separates the proteins based on affinity
What does Gel Electrophoresis seperate?
This can be used on charged molecules like DNA, nucleic acids and proteins
What is Native Gel Electrophoresis?
This does not denature the molecules, separation is by shape, size and charge. The overall charge of the protein will also effect the rate at which it travels
What is SDS-PAGE
A compound is added to the sample which denatures proteins and makes them linear. This gives them all the molecules on equally negative charge and denatures them, separating proteins by size alone
What does Isoelectric point separate?
Soluble proteins using their isoelectric points
What is the Isoelectric point of a protein?
The pH at which it has no net charge, at this pH the protein will precipitate out of solution
What three techniques are combined to separate proteins
Isoelectric points, gel electrophoresis and a pH gradient
How do these 3 techniques separate proteins?
A gel containing a pH gradient with a solution containing a mixture of proteins is loaded, an electrical current will be passed through and the proteins will move through the gel and precipitate out the solution when the protein reaches the pH it matches (The precipitate shows up as a solid band)
Why does the protein not move any further when it reaches its pH on the pH gradient?
It has no further net charge
Why are antibodies useful in the detection of specific proteins?
Because antibodies are specific to particular antigens and soonly bind to those specific antigens
