Biology - Infection and Response

What are pathogens?

Microorganisms that cause infectious disease in animals and plants.

What are four examples of pathogens?

• Viruses

• Bacteria

• Fungi

• Protists

How can pathogens spread?

• Contaminated Food

• Air (Sneezing or Coughing)

• Water

• Direct Contact

How do bacteria make us feel ill?

By producing toxins that damage tissues in the body

What are three examples of viral diseases?

• Measles

• Human Immunodeficiency Virus (HIV)

• Tobacco Mosaic Virus (TMV)

What are two examples of bacterial diseases?

• Gonorrhoea

• Salmonella

What is an example of fungal diseases?

Rose Black Spot

What is an example of a protist disease?

Malaria

How does the skin protect against infection?

• It acts as a physical barrier

• It secretes oils and antimicrobial which kill pathogens.

How does the nose protect against infection?

It has lots of little hairs and mucus which trap pathogens

How do the trachea and bronchi protect against infection?

They produce mucus and have cilia that trap and remove pathogens.

How does the stomach protect against infection?

It produces hydrochloric acid which kills pathogens.

How do white blood cells help to defend against infection?

Phagocytosis

Antibody Production

Antitoxin Production

What is Phagoctytosis?

The process by which white blood cells engulf and digest pathogens.

Explain how vaccinations work.

Vaccination involves introducing small quantities of dead or inactive forms of a pathogen into the body to stimulate the white blood cells to produce antibodies. If the same pathogen re-enters the body the white blood cells respond quickly to produce the correct antibodies, preventing infection.

What are advantages of vaccination?

• It can provide herd immunity

• It has helped control the spread of communicable diseases (Measles is very rare now and Smallpox doesn’t occur now)

• It helps prevent epidemics

What are disadvantages of vaccinations?

They don’t always work

They can cause a bad reaction in the patient (such as swelling or seizures)

How do antibiotics work to help prevent disease?

They kill infective bacteria within the body..

Why is it difficult to develop drugs that cure viral infections?

Viruses occupy our cells so we cannot kill them without hurting our own cells.

What is the heart drug Digitalis made of?

Foxgloves

What is the painkiller aspirin made of?

Willow (Tree)

What is the antibiotic penicillin made of?

Penicillium mould

What are drugs tested for?

Toxicity, Efficacy and Dosage.

What is the first stage of preclinical testing?

The drugs are tested on human cells and tissue in the lab.

What is the second stage of preclinical testing?

The drugs are tested on live animals.

What is the law for drug testing in the UK?

You must test on two different live animals.

What are advantages of animal testing?

It is the safest way to make sure a drug isn’t dangerous before it is given to humans

What are disadvantages of animal testing?

• It is cruel

• Animals are so different to us that testing on them is pointless.

What is the first stage of clinical trials?

The drug is tested on healthy volunteers to make sure it doesn’t have any harmful side effects.Normally a very low dose is given at the beginning

What is the second stage of clinical trials?

The drug is tested on people who are suffering from the illness. This is to find the optimum dose

When are the results of the trials published?

After they’ve been through peer review. This helps to stop false claims.

What is the last step of making monoclonal antibodies?