B3 - Infection and Response Flashcards
What are pathogens?
Microorganisms that enter the body and cause disease.
Can both plants and animals be infected by pathogens?
Yes.
How small are bacteria compared to body cells?
About 1/100th the size.
How do bacteria make you feel ill?
By producing toxins that damage cells and tissues.
Are viruses considered cells?
No, they are not cells.
How do viruses reproduce?
By using the host cell’s machinery to replicate themselves.
What happens to the host cell after a virus replicates?
The cell usually bursts, releasing new viruses.
What are protists?
Single-celled eukaryotes.
Can protists be parasites?
Yes, some protists are parasites.
What is a vector in relation to protists?
An organism that transfers the protist but does not get the disease itself.
What are the two forms of fungi?
Single-celled and multicellular (made up of hyphae).
How do hyphae cause diseases?
By growing and penetrating human skin and the surface of plants.
What can hyphae produce that spreads diseases?
Spores.
Give an example of a disease spread by water.
Cholera
Diarrhoea
Typhoid
How can pathogens be spread through the air?
By being carried in droplets produced when coughing or sneezing.
What is an example of an airborne pathogen?
Influenza virus (the flu)
Chickenpox
How can pathogens be transmitted through direct contact?
By touching contaminated surfaces.
What is an example of a fungus spread by direct contact?
Athlete’s foot.
Ringworms.
What are the three main stages in drug testing?
1) Preclinical testing on human cells and tissues
2) Testing on live animals
3) Clinical trials on human volunteers
Each stage is crucial for assessing the drug’s efficacy, toxicity, and safety.
What is the purpose of preclinical testing?
To test drugs on human cells and tissues in the lab and determine their effects on whole body systems
This stage helps to assess the initial safety and efficacy of the drug.
Why must some drugs be tested on live animals?
To evaluate efficacy, toxicity, and optimal dosage
Whole animals provide an intact physiological system for comprehensive testing.
What does the law in Britain require regarding animal testing for new drugs?
Any new drug must be tested on two different live mammals
This regulation aims to ensure safety before human trials.
What is the first step in clinical trials?
Testing the drug on healthy volunteers
This ensures that the drug does not cause harmful side effects in a normal body.
How is the dosage adjusted during clinical trials?
A very low dose is given initially and gradually increased
This approach helps identify the optimum dose with minimal side effects.
What is the purpose of using a placebo in clinical trials?
To measure the actual effect of the drug versus no treatment
This helps account for the placebo effect, where patients may feel better simply because they expect to.
What does ‘blind’ mean in the context of clinical trials?
Patients do not know whether they are receiving the drug or placebo
This helps to eliminate bias in patient responses.
What is a double-blind study?
Neither the patient nor the doctor knows who receives the drug or placebo
This further reduces bias in the collection and analysis of data.
Fill in the blank: The optimum dose is the dose of drug that is the most _______ and has few side effects.
[effective]
Finding the optimum dose is crucial for maximizing therapeutic effects while minimizing risks.
What is the primary function of many drugs?
Many drugs relieve symptoms without curing the underlying problem
For example, cold remedies do not actually cure colds.
How do antibiotics work?
Antibiotics kill or prevent the growth of bacteria causing the problem
Different antibiotics target different types of bacteria.
What has been the impact of antibiotics on communicable diseases?
The use of antibiotics has greatly reduced the number of deaths from communicable diseases caused by bacteria.
What can cause bacteria to become resistant to antibiotics?
Bacteria can mutate, leading to resistance against antibiotics.
What happens to non-resistant bacteria when an infection is treated with antibiotics?
Only the non-resistant strains are killed, allowing resistant bacteria to survive and reproduce.
What is an example of a serious infection caused by antibiotic-resistant bacteria?
MRSA (meticillin-resistant Staphylococcus aureus) causes serious wound infections.