Things I forget Flashcards
What is the definition of risk?
the likelihood of harm arising from exposure to hazard
give 2 examples of a control measure
- using appropriate handling technique
- protective clothing and equipment
- aseptic technique
What is a linear dilution series?
they differ by an equal interval
ex:
0.1, 0.2, 0.3 and so on
What is a log dilution series?
they differ by s constant proportion
ex:
10^-1, 10^-2, 10^-3 and so on
How does affinity chromatography work?
- a solid matrix or gel column is created with specific molecules bound to the matrix or gel
- soluble, target proteins in a mixture, with a high affinity for these molecules become attached to them as the mixture washes down the column
- other non-target molecules with a weaker affinity are washed out
What happens during electrophoresis?
charged macromolecules move through an electric field applied to a gel matrix
How are proteins separated during electrophoresis?
native gels separate proteins by their shape, size and charge
native gels do not denature the molecule so that the separation is by shape, size and charge
What is the isoelectric point?
the pH at which a soluble protein has no net charge and will precipitate out of solution
Explain how proteins are separated using their isoelectric points in electrophoresis
- soluble proteins can be separated using an electric field and a pH gradient
- a protein stops migrating through the gel at its isoelectric point in the pH gradient because it has not net charge
What are immunoassay techniques used for?
used to detect and identify specific proteins
How do immunoassays work?
- use stocks of antibodies with the same specificity, known as monoclonal antibodies
- an antibody specific to the protein antigen is inked to a chemical ‘label’
- the ‘label’ is often a reporter enzyme producing a colour change, but chemiluminescence, fluorescence and other reporters can be used
- in some cases the asset uses a specific antigen ti detect the presence of antibodies
What is western blotting?
- used after SDS-PAGE electrophoresis
- the separated proteins from the gel are transferred (blotted) onto a solid medium
- the proteins can be identified using specific antibodies that have reporter enzymes attached
What do culture media do?
promote the growth of specific types of cells and microbes
What are animal cells grown in?
medium containing growth factors from serum
What is the proteome?
the proteome is the entire set of proteins expressed by a genome
What are genes that do not code for proteins called?
non-coding RNA genes
What are the receptors for hydrophobic signalling molecules?
Transcription factors
What are transcription factors?
proteins that when bound to DNA can either stimulate or inhibit initiation of transcription
What does the hormone receptor complex do?
Moves to the nucleus where it binds to specific sites on DNA and affects gene expression
What DNA sites does the hormone receptor complex bind to and what effect does this have?
- Binds to specific DNA sequences called hormone response elements (HREs)
-Binding at these sites influences the rate of transcription, with each steroid hormone affecting the gene expression of many different genes
How do transmembrane receptors act as signal transducers?
By converting the extracellular ligand-binding event into intracellular signals, which alters the behavior of the cell
Describe what happens once insulin binds to its receptor
- Binding of insulin to its receptor causes a
conformational change that triggers
phosphorylation of the receptor. - This starts a
phosphorylation cascade inside the cell, - Which eventually leads to GLUT4-containing
vesicles being transported to the cell
membrane.
How is the resting membrane potential restored?
inactivation of the sodium channels and the opening of potassium channels
Explain the steps of the travel of the action potential
1) Binding of a neurotransmitter triggers the opening of ligand-gated ion channels at the synapse
2) Ion movement occurs and there is depolarisation of the plasma membrane.
3) If sufficient ion movement occurs, and the membrane is depolarised beyond a threshold value, the opening of voltage-gated sodium channels is triggered and sodium ions enter the cell down their electrochemical gradient
4) this leads to a rapid and large change in the membrane potential
5) a short time after opening the sodium channels become inactivated
6) voltage-gated potassium channels then open to allow potassium ions to move out of the cell to restore the resting membrane potential
