What is an antigen?
A chemical produced by the white blood cells
A chemical on the surface of the pathogen
A microbe that causes a disease
How do vaccines protect people against disease infections?
Vaccines introduce a live version of the pathogen.
Vaccines stimulate antigens to be produced by the red blood cells.
Vaccines introduce pathogenic antigens, which stimulate the white blood cells to produce antibodies.
How do antibiotics work?
Antibiotics kill bacterial cells
By relieving disease symptoms
Antibiotics kill viruses
Why do scientists grow bacteria in the laboratory?
To allow them to check the effectiveness of antibiotics or antibacterial substances at killing them
To be able to calculate the number of bacteria in a population
To allow infectious diseases to be cultured
Why do schools and colleges grow bacterial plates at 25 degrees Celsius?
This is the optimum temperature for bacterial growth
This is a reliable temperature for schools to get reproducible results
The temperature prevents harmful pathogens growing
What is a zone of inhibition?
Area where bacterial growth is increased
Area where the growth of the bacteria has been slowed or stopped
Area where bacteria can be grown
How do you measure the size of the zone of inhibition?
\(\pi\) sq r
\(\pi\) sq r h
Length × width
How are drugs checked for safety?
Drugs are tested for efficacy, toxicity and dosage
By giving them to humans first
By giving people a placebo
What are the different stages of drugs trials?
Testing it on humans to see if the side effects are harmful
On human volunteers first and then on animals
Preclinical trials using cells, tissues and animals. Then clinical trials using healthy human volunteers and patients.
What type of drug trials are there?
Blind and partially blind trials
Blind, double blind and open trials
Fully open trials only