unit one-Laboratory techniques for biologists Flashcards
Describe buffers
A solution where adding acids or alkalis have a small effect on pH. This allows pH in a reaction mixture to be kept constant
What is a colorimeter
Used to quantify concentration and turbidity
What is absorbance used for in colorimetry
To determine concentration of a coloured solution using suitable wavelength filters
What does determining percentage transmission in colourimetry mean
To determine turbidity
Such as cells in suspension
Describe centrifugation
Spin samples at high speedy to seperate material according to density
What happens to the components in centrifugation
High density- form pellet at bottom
Low density- form supernatant on top
What is chromatography used for
What is the speed due to
Seperate different substances such as amino acids and sugars. Speed is due to differing solubilitues with the solvent
Why is thin layer chromatography better
Faster. Better separations
What is affinity chromatography used for
Seperate target proteins
Describe gel electrophoresis
Charged macromolecules move through an electric field applied to a gel matrix
What is a native gel
Do not denature the molecule. Separate proteins by their shape size and charge
What is an sds-page
Denatures moleculesSeperate molecules by size alone
What is an isoelectric point iep
The pH at which a soluble protein has no net charge and will precipitate out of solution
How does ieps seperate proteins in electrophoresis
Sublime proteins can be aerated using an electric feild and a pH gradient. Protein stops migrating at iep in pH gradient bc it has no net charge
what is Immunoassay used for
are used to detect
and identify specific proteins
describe how immunoassay works
These techniques use stocks of antibodies
with the same specificity, known as
monoclonal antibodies
what is Western blotting is a technique,
used after
SDS–PAGE electrophoresis
The separated proteins from the gel are
transferred (blotted) onto a solid medium
how are antigens identified
antibodies that have reporter enzymes
attached
bright feild microscopy
used to observe whole organisms
part of organims
thin sections of dissected tissue
light needs ot be able to pass thrpigj
fluorescent microscopy
use fluorescent labels
certain molecules or structures within cell tissues
aseptic technique
eliminate unwanted microbial contaminants when culturing microorganisms
sterilising- heat or chemical
what is a growth factor
proteins that promote cell growth
what are the two forms of cells that can be grown in culture
primary cell lines-can divide a limited number of times
tumour cell lines- divide unlimited times
counting cells
use a haemocytometer. estimate cell numbers in a liquid culture.
vital staining
living cells prevent staining.
using a haemocytometer equation
cell density= average cells per square/ volume of small square
