Biochemistry and Microbiology Remedial Action

During preparation for external examination, it has been found that there are a few pieces of information missing from your assignments.  The following virtual learning classes have been created to allow you to complete the remedial tasks required, as discussed by your tutor.

Factors effecting enzyme concentration


The activity of an Enzyme is affected by its environmental conditions. Changing these alter the rate of reaction caused by the enzyme. In nature, organisms adjust the conditions of their enzymes to produce an Optimum rate of reaction, where necessary, or they may have enzymes which are adapted to function well in extreme conditions where they live.


During practical sessions you have already determined the effect of pH and temperature. In the following. Throughout this section we will be investigating the effect of substrate and enzyme concentration of the rate at which a reaction occurs.

Effects of substrate concentration on enzyme activity

The substrate is the molecule that a reaction.

Increasing the substrate concentration the rate of reaction. This is because more substrate molecules will be  with enzyme molecules, so more product will be formed.

However, after a certain concentration any increase will have  effect on the rate of reaction, since   concentration will no longer be the  factor. The enzymes will effectively become , and will be working at their maximum possible rate. The rate of reaction will not be able to increase any further.

Effect of substrate concentration answers

  • Increasing Substrate Concentration increases the rate of reaction. This is because more substrate molecules will be colliding with enzyme molecules, so more product will be formed.
  • However, after a certain concentration, any increase will have no effect on the rate of reaction, since Substrate Concentration will no longer be the limiting factor. The enzymes will effectively become saturated, and will be working at their maximum possible rate

Effect of enzyme concentration on enzyme activity

  • As enzyme concentration increases
    rate of reaction will increase
  • More enzymes means
    more collisions with substrate molecules
  • will only have an effect up to a certain concentration as
    there is only a certain number of substrate molecules present

Effect of enzyme concentration answers

COSHH regulation


Using micro-organisms at work can put people's health at risk, so the law requires employers to control exposure to microorganisms to prevent ill health.  employers have to protect both employees and others who may be exposed by complying with the CONTROL OF SUBSTANCES HAZARDOUS TO HEALTH (COSHH) regulations.

Adhering to COSHH regulations

  • Asses the risks to health arising from using tis micro-organism
  • Decide what precautions are needed
  • prevent or adequately control exposure to the micro-organism
  • Ensure that control measures are used and maintained properly
  • Monitor the exposure to the micro-organism
  • Carry out appropriate health surveillance where necessary
  • prepare plans and procedures to deal with accidents, incidents and emergencies
  • Ensure employees are properly informed, trained and supervised
In order to adhere to COSHH regulations when working with micro organisms there are 8 steps that must be taken. Can you put these in the correct order

hazards when working with specific micro organisms

There are many types of micro-organisms, each with their own individual hazards. However we will be concentrating on only 5 types: Salmonella species, vibrio cholera, mycobacterium tuberculosis, plasmodium species and HIV.


Salmonella - There are 6 different subtypes of salmonella each of which are to humans.  Human infection usually occurs when consuming contaminated food and water, contact with infected faeces, as well as contact with infective animals, animal feed or other infected humans. Salmonella can cause 4 different clinical manifestations