TESTS

• What are reagent strips?


  Test strips used to detect and measure substances in a liquid or on a surface; can be used to test for reducing sugar, eg. glucose.
• What is a colourimeter?

  It is an instrument used to determine concentration, a qualitive measure of the absorption or transmission of light by a coloured solution. The more concentrated the solution, the more light it will absorb and less light it will transmit. It works by comparing the light transmitted to a standard.
• What is a tristimulus colourimeter?


  These measure colour using the three sensors that correspond to the red, green and blue components of light, similar to how the human eye perceives colour.
• What are photometric colourimeters?

  These measure the absorbance of a specific wavelength of light passing through a solution, often used in chemistry to determine the concentration of substances in a liquid.
• How is a colourimeter calibrated?

  Using distilled water.
• What are biosensors?


  These use biological components to determine the presence and concentration of molecules.
• What is the analyte?


  The compound being investigated.
• What is molecular recognition?


  The specific interaction between molecules based on their complementary shapes and chemical properties.
• What is molecular recognition in testing with enzymes and antibodies?

  Where a protein or single DNA strand is immobilised to a surface, where it will interact with the investigation molecule, eg. glucose test strip.
• What is transduction in testing?


  An interaction that causes a change in a transducer, and a transducer detects a change (eg. pH), and produces a response such as the release of dye on a test strip.
• What is a transducer?


  Molecules or structures that convert one form of signal into another within a biological system, playing a crucial role in signal transduction; a cell responds to external stimuli and converts it into a specific cellular response.
• What are molecular transducers?

  Proteins or other molecules that relay signals from receptors on the cell surface to the appropriate intracellular targets, eg. g-proteins, that convey signals from receptors to enzymes or ion channels, and second messengers, that amplify and relay signals inside the cell (cAMP and calcium ions).
• What are sensory transducers?


  Specialised cells or structures in sensory organs that convert external physical stimuli, into electrical and chemical signals in the nervous system.
• How do you separate amino acids?

  Chromatography, consisting of the mobile and stationary phase.
• What is the stationary phase of chromatography?

  This is where a layer of silica gel is applied to a rigid surface, with aminos added to one end. This end is submerged in an organic solvent, which moves through the gel.
• What is the mobile phase?


  This is the stage in which the amino acids are picked up and move through the the stationary phase, separating as they move.
• What is the rate of chromatography dependant on?

  It is dependant on the interactions (hydrogen bonds) between the amino acids and the gel in the stationary phase, and the solubility of the amino acids in the mobile phase; allowing different travelling distances.