1.1 Flashcards
hazard
a factor or object that can cause harm upon exposure.
E.g. Pathogenic organisms, toxic and corrosive chemicals, heat and flammable substances, equipment.
risk
the likelihood of harm arising from exposure to a hazard
risk assessment
Involves identifying control measures to minimise risk
control measures
include using appropriate handling techniques, PPE and aseptic technique
pathogenic organism
an organism that can cause disease
aseptic technique
technique used to reduce contamination
autopipette
used to measure very small volumes of liquid accurately
burette
used to dispense precise volumes of liquid reagents
linar dilution
dilutions of a solution which differ by a constant proportion
standard curve
to determine the concentration of an unknown solution
buffer
used to control pH, allows pH of a solution to be kept constant
colorimeter
used to quantify the concentration (absorbance) or turbidity (uses transmission) of a solution, use blank to calibrate
spectrophotometer
used to determine the spectra reflectance at each wavelength, more complex analysis than colorimeter
centrifugation
used to separate substances of differing density
supernatant
a solution of lower density materials that is formed at the top of an Eppendorf tube after centrifugation
pellet
higher density materials that form at the bottom of an Eppendorf tube after centrifugation
chromatography
a separation technique used to separate the components of a mixture (amino acids, sugars, proteins).
paper chromatography
to separate pigments in a leaf, uses polar cellulose fibres, polar components bind, non-polar don’t bind as readily and travel further.
thin layer chromatography
to separate different substance such as amino acids and sugars but stationary phase is a strip of absorbent material (e.g. silica gel)
mobile phase
the mixture to be separated during chromatography is dissolved into this fluid.
stationary phase
components of mixture are separated as they move through this, changes depending on chromatography type.
affinity chromatography
used to separate proteins
affinity
the degree to which a substance is attracted and tends to bind to another
What are the basics of gel electrophoresis (PAGE)
charged macromolecules, such as proteins or nucleic acids move through an electric field applied to a buffered gel matrix
What is native PAGE?
do not denature the molecules being separated - they preserve structure and function
separation is by shape, size and charge
What is SDS-PAGE?
contain sodium dodecyl sulfate which denatures molecules passing through
gives molecules a negative charge, separating proteins by size alone
simple to carry out but structure and function of protein is lost
What is the isolelectric (IEP) point?
the pH value at which these proteins are electrically neutral, with surface charges that are balanced
pH below IEP = +
pH above IEP = -
at IEP the protein loses water solubility and precipitates out of solution
What are imunoassay techniques?
used to detect/identify specific proteins, use antibodies called monoclonal antibodies which are linked to chemical ‘label’ of an enzyme that changes colour or that shows chemiluminescence, fluorescence or radioactivity
specific antigens bind and colour change occurs
What is western blotting?
used after SDS-PAGE, the separated proteins are blotted to a solid medium and dried
proteins labelled using antibodies then antibody with ‘label’ is added so that it is visible to the eye
What is bright field microscopy?
examines whole organisms, parts of organisms, thin dissected tissue or cells
What is fluorescence microscopy?
uses UV light to detect specific fluorescent stains which bind to and visualise certain molecules or structures within cell or tissues
Aseptic technique
eliminates unwanted microbial contaminants when culturing micro-organisms or cells
involves sterilisation of equipment and culture media by heat or chemical means
How can a microbial culture be started?
using an inoculum of microbial cells on an agar medium or in a broth with suitable nutrients
What are animal cells grown in?
medium containing serum which contains growth factors
What are growth factors?
proteins that promote growth and proliferation
Why would you want to plate a microbial culture?
plating of liquid culture onto solid media allow number of colony-forming units to be counted and density of cells estimated
serial dilution often needed to achieve
What are haemocytometers?
microscopic grids used to estimate cell numbers in a liquid culutre
vital staining needed
What is vital staining?
used to identify and count viable cells because the stain can distinguish between cells that are alive or dead
