Pathogens and Disease Flashcards

Practice flashcards covering pathogens, communicable diseases, immune responses, and medical treatments based on the lecture notes.

What is a communicable disease?

A disease caused by a pathogen which can be passed between animals or plants eg. flu.

How do bacteria cause disease within the body?

Once inside the body, they divide rapidly by binary fission. They kill cells and produce harmful toxins.

What are three ways in which pathogens can be spread?

By air (droplet infection), by water (fungal spores), and by direct contact.

Give four ways in which the spread of pathogens can be reduced.

Hygiene (handwashing, disinfectants), reducing contact (quarantine), removing vectors (pesticides, habitat removal), and vaccination.

Why is it especially important to prevent the spread of viral diseases?

Scientists have not yet developed cures for many viral diseases.

What is measles and what are its main symptoms?

A serious viral disease that can cause blindness and brain damage; symptoms include a fever and a red skin rash.

What is the difference between HIV and AIDS?

HIV is a virus that damages the immune system; AIDS is the condition resulting from a long-term HIV infection. There is no cure or vaccine.

How can the spread of HIV/AIDS be prevented?

Use of condoms, screening of blood for transfusions, not sharing needles, bottle-feeding by HIV-positive mothers, and use of antiretroviral drugs.

What is the effect of tobacco mosaic virus (TMV) on plants?

It causes leaf discolouration which prevents photosynthesis, thereby reducing crop yield.

How is tobacco mosaic virus (TMV) spread?

Through contact between infected and healthy plants, or by insects acting as vectors.

Where is salmonella bacteria typically found?

In raw meat, poultry, and eggs.

What are the symptoms of salmonella food poisoning?

Fever, abdominal cramping, vomiting, and diarrhoea.

How can the spread of salmonella be limited?

Vaccinating animals intended for consumption, keeping raw meat separate, disinfecting surfaces, and thoroughly cooking meat.

What is gonorrhoea and how is its spread controlled?

A sexually transmitted bacterial infection; controlled through the use of antibiotics and condoms.

What are the characteristics of rose black spot?

A fungal disease causing purple or black spots on leaves, causing them to turn yellow and drop prematurely, which reduces photosynthesis.

What causes malaria and how is it spread?

Malaria is caused by protist pathogens and is carried from host to host by mosquitoes.

How can the spread of malaria be reduced?

Using insecticides, using insect nets, removing stagnant water to prevent mosquito breeding, and antimalarial drugs.

How does the skin act as a barrier against pathogens?

It acts as a physical barrier, forms scabs when wounded, secretes antimicrobial substances, and has healthy flora that compete with pathogens.

How does the respiratory system defend against pathogens?

The nose has hairs and mucus to trap pathogens; the trachea and bronchi have mucus and ciliated cells that move mucus to the mouth to be swallowed.

How does the stomach prevent infection?

It secretes hydrochloric acid which kills any pathogens present.

How does phagocytosis protect the body?

White blood cells (phagocytes) ingest and destroy pathogens so they cannot infect more cells.

How does antibody production protect against disease?

White blood cells produce antibodies complementary to a specific antigen, causing pathogens to clump for destruction and allowing for rapid reproduction if a second infection occurs.

What is the function of antitoxins?

Antitoxins bind to toxins released by pathogens and neutralise them.

How does a vaccination work?

It involves a dead or inactivated form of a pathogen that stimulates white blood cells to produce antibodies and memory cells.

What is herd immunity?

When a sufficiently high proportion of a population is immune to a disease (usually via vaccination), which limits the spread of that disease.

What are the disadvantages of vaccinations?

They are not guaranteed to work (may not protect against all strains) and there may be side effects or adverse reactions.

What is the function of antibiotics?

They are drugs like penicillin that kill bacterial pathogens inside the body without killing human cells.

Why can antibiotics not be used to treat viral diseases?

Viral pathogens live inside host cells, making it difficult to kill the virus without destroying human cells.

What causes antibiotic resistance?

Mutations lead to resistant bacteria which survive, reproduce, and pass on their alleles.

How can antibiotic resistance be prevented?

Avoid overuse/unnecessary use and ensure patients finish their full antibiotic courses.

What is the role of painkillers in treating infectious diseases?

Painkillers treat the symptoms but do not kill the pathogens.

What are the four qualities of a good medicine?

Effective, safe, stable, and able to be taken in and removed easily.

What is the process of clinical testing for a new drug?

Testing low doses on healthy volunteers, then testing on patients to find the optimum dose, often using a placebo group to assess efficacy.

What is the difference between a single-blind and a double-blind trial?

In single-blind, only the doctor knows who gets the drug; in double-blind, neither the doctor nor the patient knows, which helps remove bias.

What is a peer review?

A process where scientists knowledgeable in the field check over the results of drug trials.