key area 1 Flashcards
linear dilution
Concentrations of each solution are separated by an equal interval e.g. 0.1, 0.2, 0.3 (does not have to be a factor of 10
log dilution
Dilutions in a log dilution series differ by a constant proportion, for example 10-1, 10-2, 10-3
standard curve
Method that is used to determine the concentration of a solution by using known concentrations which are measured and graphed
buffers
Sterile solutions which control pH.
colorimeter
Device that is used to measure the absorbance of a specific wavelength of light by a solution.
absorbance
How much light has been absorbed by the sample.
transmission
How much light passed through the sample without being absorbed. % transmission can calculate the turbidity of a substance
centrifugation
A process which uses centrifugal forces to separate components of a mixture.
pellet
Forms at the bottom (higher density materials) after centrifugation.
supernatant
liquid at the top (lower density materials) after centrifugation.
chromatography
A set of techniques which separates the components of a mixture.
thin layer chromatography
Used for separating amino acids and sugars, a strip of absorbent material on a non reactive binding, the amount they travel depends on the solubility and how much they bind to the stationary phase
affinity chromatography
Relies on the binding interactions between a protein and an immobilised ligand. Use to separate proteins.
paper chromatography
uses pigments in a leaf, polar components will bind to cellulose fibres quickly and don’t travel up the paper
electrophoresis
A process which applies an electric current across a gel to separate components of a mixture.
native gel electrophoresis
Type of electrophoresis which separates proteins by their shape, size and charge.
SDS page electrophoresis
Type of electrophoresis which separates proteins by size alone.
isoelectric point
The pH at which a soluble protein has no net charge and will precipitate out of solution.
bright field microscopy
Commonly used to observe whole organisms, parts of organisms, thin sections of dissected tissue or individual cells. uses stains to improve clarity
fluorescent microscopy
Specific fluorescent labels to bind to and visualise certain molecules or structures within cells or tissues.
haemocytometer
A device which allows an estimation of the concentration of cells in a sample to be made.
aseptic techniques
Used to eliminate unwanted microbial contaminants when culturing micro-organisms or cells.
examples of aseptic techniques
blue flame on the loop, chemicals to clean work surface, flame the glass neck of bottles
microbial culture
Can be started using an inoculum of microbial cells on an agar medium, or in a liquid broth with suitable nutrients.
primary cell line
A culture which will only divide a limited number of times and then die
tumour cell line
A culture which does not have limitation, and will grow and divide indefinitely in cell culture.
typical cell culture
Contains water, salts (Murashige and Skoog salts for plants), amino acids, vitamins and glucose.
complex cell culture
Contains growth factors (proteins) from serum to promote cell growth and division (proliferation)
vital staining
Estimates of cell counts can be made can be made using trypan blue dye, which is absorbed by dead cells. Required to identify and count viable cells.
immunoassay
Techniques which use antibodies linked to reporter enzymes to cause a colour change in the presence of a specific antigen.
monoclonal
Type of antibodies can be used to detect both the presence and concentration of a protein within a solution.
western blotting
Allows scientists to identify specific proteins which are present in a cell sample. Technique used after SDS-PAGE electrophoresis where the membrane is then probed for the protein of interest using a specific antibody that is linked to a detectable label.
