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.
Fill in the blank: Many drugs originally came from _______.
[plants]
What role do plants play in drug development?
Plants produce chemicals to defend against pests and pathogens, some of which can treat human diseases.
What is aspirin used for and where was it developed from?
Aspirin is used as a painkiller and was developed from a chemical found in willow.
What is digitalis used for and where was it developed from?
Digitalis is used to treat heart conditions and was developed from a chemical found in foxgloves.
Who discovered penicillin and how?
Alexander Fleming discovered penicillin when he noticed that mould on a Petri dish killed bacteria.
What is the primary purpose of vaccinations?
To prevent diseases before they occur
Vaccinations allow the body to build immunity without the individual suffering from the actual disease.
How do vaccinations work in the body?
They inject small amounts of dead or inactive pathogens that carry antigens
This process stimulates the immune system to produce antibodies.
What happens when live pathogens of the same type appear after vaccination?
White blood cells can rapidly mass-produce antibodies to kill off the pathogen
This rapid response helps prevent illness.
What is an epidemic?
A big outbreak of disease
Epidemics can be prevented through widespread vaccination.
What is herd immunity?
When a large percentage of the population is vaccinated, reducing disease spread
This protects even those who are not vaccinated.
List four symptoms of Salmonella infection.
- Fever
- Stomach cramps
- Vomiting
- Diarrhoea
These symptoms are caused by toxins produced by the bacteria.
What preventative measure is taken in the UK for poultry against Salmonella?
Vaccination
Most poultry, such as chickens and turkeys, are vaccinated to control the spread of the disease.
What is Gonorrhoea?
A sexually transmitted disease (STD) caused by bacteria
What are two symptoms of Gonorrhoea?
- Pain when urinating
- Thick yellow or green discharge from the vagina or penis
Which antibiotic was originally used to treat Gonorrhoea?
Penicillin
Resistance to penicillin has made treatment more challenging.
What are two methods to prevent the spread of Gonorrhoea?
- Treatment with antibiotics
- Use of barrier methods of contraception (e.g., condoms)
These methods are effective in reducing transmission.
What can be done to destroy vectors that spread disease?
- Use insecticides
- Destroy their habitat
This prevents them from breeding and spreading disease.
How does isolating infected individuals help in disease control?
It prevents them from passing the disease to others
Isolation is a key strategy for managing communicable diseases.
What is measles and how is it spread?
Measles is a viral disease spread by droplets from an infected person’s sneeze or cough.
It can lead to serious complications like pneumonia and encephalitis.
What are the symptoms of measles?
A red skin rash and fever.
Fever is often accompanied by other symptoms such as cough and runny nose.
How is HIV transmitted?
HIV is spread by sexual contact or by exchanging bodily fluids such as blood.
Sharing needles when taking drugs is a common transmission route.
What initial symptoms does HIV cause?
Flu-like symptoms for a few weeks.
Many people do not experience symptoms for several years afterward.
What does HIV do to the immune system?
The virus attacks immune cells, leading to impaired immune function.
This can lead to late stage HIV infection, known as AIDS.
What is the tobacco mosaic virus (TMV)?
TMV is a virus that affects many plant species, causing a mosaic pattern on leaves.
It impacts photosynthesis, affecting plant health.
What is rose black spot?
Rose black spot is a fungal disease that causes purple or black spots on rose leaves.
Affected leaves may turn yellow and drop off, hindering plant growth.
How does rose black spot spread?
It spreads through the environment in water or by the wind.
Gardeners can manage it with fungicides and removing affected leaves.
What is the role of photosynthesis in plant growth?
Photosynthesis produces glucose, which is essential for plant growth.
Less photosynthesis means reduced energy for the plant.
What causes malaria?
Malaria is caused by a protist that has part of its life cycle inside mosquitoes.
Mosquitoes act as vectors, transmitting the disease when they feed.
What are the symptoms of malaria?
Malaria causes repeating episodes of fever.
It can be fatal if not treated properly.
How can the spread of malaria be reduced?
By stopping mosquitoes from breeding and using insecticides and mosquito nets.
Preventative measures are crucial in malaria-endemic regions.
What features does the human body have to stop pathogens from entering?
Hairs and mucus in the nose trap particles that could contain pathogens
These features are part of the body’s initial defense system.
What is the process called when white blood cells engulf and digest foreign cells?
Phagocytosis
This is one of the three lines of attack that the immune system uses against pathogens.
What are antigens?
Unique molecules on the surface of invading pathogens
They trigger the immune response by prompting the production of antibodies.
What type of white blood cells produce antibodies?
B-lymphocytes
They are crucial for the adaptive immune response against specific pathogens.
What happens when a person is infected with the same pathogen again?
White blood cells rapidly produce antibodies to kill it
This leads to natural immunity to that pathogen.
What do antitoxins do?
Counteract toxins produced by invading bacteria
This is part of the immune system’s defense against harmful substances.
List the three lines of attack used by the immune system against pathogens.
- Consuming them (phagocytosis)
- Producing antibodies
- Producing antitoxins
These strategies help eliminate or neutralize pathogens.
