1.1 : lab techniques for biologists Flashcards
what is a risk assessment
a risk assessment is done before every experiment and identifies control methods to minimize the risk of hazards
what are some control methods
PPE, appropriate techniques, protective clothing, aseptic techniques
what are some lab hazards
toxic and corrosive chemicals, heat, flammable substances, pathogens, mechanical equipment
what is a dilution series
an important lab technique tat reduces the concentration of a substance within a soloution
what is linear dilution
soloution that differs by an equal interval
e.g. 0.1, 0.2, 0.3
what is log dilution
soloution that differs by a constant proportion
e.g. 10-1, 10-2, 10-3
what can a dilution series make easier
allows easier counting of colonies when added to an agar plate
what is a colorimeter
used to measure the absorbance of a specific wavelength and can be used to quantify the concentration and turbidity of a solution
IEP charges
neutral at the isoelectric point
positive below the isoelectric point
negative above isoelectric point
what is formed by isoelectric points
a precipitate
what is a isoelectric point
is the pH at which a soluble proteins has no net charge which allows the separation of a proteins
how does native electrophoresis separate a protien
separates by size,shape and charge as it does not denature the molecule
how does SDS-page electrophoresis separate a protien
sds-page denatures molecules giving all a negative charge this means they must be separated by size
what is gel electrophoresis
seperation technique which seperates protiens and nucleic acids based on shape size and charge
what is centrifugation
a separation technique that is used to separate substances by density by spinning a substance at a high speed which allows most dense substances to form a pellet and least dense to remain suspended in supernatant
what is a pH buffer
used to control pH allowing the addition of an acid or alkali to a solution to have little effect
what is a standard curve
graph of a known plotted concentration that is used to determine an unknown concentration
what is turbidity and how is it determined
the cloudiness of a solution and the percentage of transmission of the colorimeter is used to determine turbidity
how is a colorimeter calibrated
by a cuvette containing distilled water being used as a blank
what is affinity chromatography?
relies on binding action, a ligand is immobilized within a column and a protein mix is passed through this column, the target protein binds to the complementary ligand and remain in the column while the rest is washed out, results in a pure sample of target protein
what is thin layer chromatography?
method that uses a stationary phase of absorbent material such as silica, the solvent moves through the stationary phase and travels slow or fast based on solubility.
what is paper chromatography?
stationary phase is a strip of chromatography paper, mixture is placed at bottom of paper then in solvent, the solvent travels up paper and carries the mixture at different rates due to properties. in this case nonpolar substances usually travel further
what are immunoassay techniques?
techniques that use monoclonal antibodies to identify proteins
what is monoclonal?
substance derived from a single molecule..
what is a reporter enzyme
used as a chemical label and can produce a color change.
what are some examples of chemical labels
reporter enzymes, chemiluminescence, fluorescence radioactivity
what is the IEP process
a solution is buffered to a specific pH, A precipitate will then form due to pH of a protein
how can gradient gel seperate a protien
used by electrical field and gradient gel, mixture stops migrating through gel at IEP as it will have no net charge
what is western blotting
process used after SDS-page, it separates proteins from gel by blotting it onto a medium and it is then probed for target proteins
fluorescence microscopy
fluorescent labels are used to bind and visualize particular proteins, the molecule absorbs specific wavelength then releases another this allows the structure to be visualized.
what is bright field microscopy
this is commonly used for observation; a sample is mounted on a slide and is illuminated from below. The light is then transmitted through the specimen to the o objective lens and to the eyepiece. the samples are then often stained for comfort.
what are aseptic techniques?
eliminates microbial contamination and is vital for a successful cell culture.
examples for aseptic techniques
sterile equipment, good personal hygiene, clean work area, counting microbial cells.
what is cell culture
is the growth of cells in an inoculum on an agar medium or in a broth flask, the process requires control of factors which promote growth of specific cell types
what is a growth factor
usually a serum, used in animal cell culture that promote cell growth and proliferation.
what is a haemocytometer
equipment used to estimate cell number in a liquid cultrue, it has a counting chamber known as liquid volume and can estimate concentration
what is vital staining
stains cells which are required to identify and count viable cells.
what is direct ELISA
an antigen binds to the surface of a well . a antibody linked with a reporter enzyme then binds also the the antigen
what is indirect ELISA
an antigen bind to the surface of a well , a primary antibody is then added also to the well and binds with the antigen, a secondary antibody is also added linked with a reporter enzyme to the primary antibody
what is sandwich ELISA
a capture antibody is added to the well, the antigen is then added and binds to the antibody. a primary antibody is added to the well and then a secondary antibody linked to a reporter enzyme binds to the primary antibody
what is ELISA
technique which uses antibodies to detect the presence of an antigen within a solution
