Infection and Response (Separate Science)

What are pathogens?

Microorganisms that can cause infectious disease

Which pathogens can cause disease?

Viruses, Bacteria, Protists and Fungi

How can pathogens be spread once they have infected a plant or animal?

Direct contact, by water or by air

How might bacteria and viruses reproduce inside the body?

Rapidly

How do bacteria make us feel ill?

They produce poisons (toxins) that damage tissues

Where do viruses reproduce?

Inside body cells, causing cell damage

Name 3 viral diseases

Measles, HIV, Tobacco mosaic Virus

What are the symptoms of measles?

Fever and red skin rash

How do we protect young children against measles?

Vaccination

How is the measles virus spread?

Inhalation of droplets from sneezes and cough

How can you control HIV?

With antiretroviral drugs

What is late stage HIV infection known as?

AIDS

What does it mean if you have AIDS?

That the body's immune system is so badly damaged it can no longer deal with other infections or cancers

How is HIV spread?

Sexual contact or exchange of body fluids such as blood when drug users share needles

Name a plant affected by Tobacco mosaic virus

Tomato

What might you see on a plant suffering from Tobacco Mosaic Virus

Distinctive mosaic pattern of discolouration on the leaves

How does Tobacco mosaic virus affect a plant's growth

Discolouration of leaves reduces growth as there is a lack of photosynthesis.

Name two bacterial diseases

Salmonella, Gonorrhoea

How is salmonella spread?

By bacteria ingested in food or in food prepared in unhygienic conditions

How do we protect poultry from Salmonella in the UK?

Vaccination

What are the symptoms of food poisoning cause by Salmonella?

Fever, Abdominal Cramps, Vomiting and Diarrhoea

What are the symptoms of gonorrhoea?

Thick yellow or green discharge from the vagina or penis, pain on urinating

How was gonorrhoea originally treated?

The use of the antibiotic penicillin

What are the issues with treating gonorrhoea today?

Resistant strains of gonorrhoea have appeared

How is gonorrhoea spread?

Sexual contact

How can the spread of gonorrhoea be treated?

Treatment with antibiotics

How can the spread of gonorrhoea be stopped?

Use of a barrier method of contraception

Name a disease caused by a fungus?

Rose black spot

What are the symptoms of rose black spot?

Purple or black spots develop on leaves which turn yellow and drop early

How does rose black spot affect the growth of a plant?

Reduces the growth due to a lack of photosynthesis

How can rose black spot be treated?

By using fungicides and/or removing and destroying the affected leaves

Name a disease caused by a protist

Malaria

What are the symptoms of malaria

Recurrent episodes of fever it can be fatal

What is the vector of malaria?

Mosquitos

How can you control the spread of malaria

By preventing the vector from breeding and using mosquito nets to avoid being bitten

What are the non-specific defence systems of the human body?

Skin, Nose, Trachea and Bronchi, Stomach

How does the skin help stop infection?

Provides a barrier to pathogens

How does the trachea and bronchi help stop infection?

Covered in sticky mucus to help trap any invading pathogens

How does the stomach help stop infection

Hydrochloric acid to destroy invading pathogen

How do white blood cells help to defend against pathogens?

Phagocytosis

Antibody production

Antitoxin production

What does a vaccination involve?

Introducing small quantities of dead or inactive forms of a pathogen into the body to stimulate the white blood cells to produce antibodies

How do white blood cells respond if they have already encountered a disease before?

Quickly

To effectively stop the spread of a pathogen what do you need to do?

Vaccinate a large proportion of the population

Give an example of an antibiotic

Penicillin

What are antibiotics?

Medicines that help to cure bacterial disease by killing infective bacteria inside the body

What is causing a problem with the treatment of bacterial infections with antibiotics

The emergence of resistant strains

What can antibiotics not kill

Viral pathogens

What are painkillers used for?

To treat the symptoms of disease

Why is it difficult to develop drugs that kill viruses

These drugs also damage the body's own tissues

How has the use of antibiotics affected the number of deaths from infectious bacterial diseases?

Greatly reduced them

Where were traditional drugs extracted from?

Plants and microorganisms

Where did the heart drug digitalis originate from?

Foxgloves

Which drug originates from willow trees?

The painkiller aspirin

Who discovered penicillin?

Alexander Fleming

Where was penicillin discovered?

From the Penicillium mould

How are most new drugs made?

Synthesised in the pharmaceutical industry

What are new drugs tested for?

Toxicity, Efficacy and Dose

What does toxicity mean?

The potential side effects that may harm people

What does efficacy mean?

How effective the drug is against the disease

What does dose mean?

The optimum quantity required to treat a disease

Where is preclinical testing undertaken?

In a laboratory

On what would preclinical testing be undertaken?

Cells, Tissues and Live Animals

Who takes part in clinical trials?

Healthy volunteers and Patients

Who would be tested on first in a clinical trial?

Healthy volunteers

What doses are given at the start of a clinical trial?

Very low doses

If a drug is found to be safe, in a clinical trial, what would then be tested for?

Optimum dose

What is a double blind trial?

A trial where neither the volunteer or the doctor knows which drug is being take

What do we call a tablet with no active ingredient?

A placebo

Why do new medical drugs have to be tested and trialled before being used?

To check they are safe and effective

If you were trying to find a new drug where might you look?

In chemicals extracted from plants

How are monoclonal antibodies produced?

From a single clone of cells

What are the antibodies specific to?

One binding site on one protein antigen

What can the antibodies target?

A specific chemical or cell in the body

What are used to produce the antibodies?

Stimulating mouse lymphocytes

What are the lymphocytes combined with?

Tumour cell

What do we call this lymphocyte and tumour cell combination?

Hybridoma cell

what can the hybridoma do?

Divide and make antibodies

How do we use monoclonal antibodies?

Diagnosis in pregnancy tests

Measure the levels of hormones and chemicals in blood or detect pathogens

Research to locate or identify specific molecules in a cell or tissue by binding to them with a fluorescent dye

treat diseases

With treating cancers, what do we bind the monoclonal antibody with?

radioactive substance

toxic drug or chemical to inhibit growth

How can plant disease be detected?

Stunted growth

Spots on leaves

Areas of decay (rot)

Grows Malformed stems or leaves

Discolouration

the presence of pests

How can diseased plants be identified?

Reference to a gardening manual or website

Taking infected plants to a laboratory to identify the pathogen

toxic drug or chemical to inhibit growth

What ion deficiency causes stunted growth?

Nitrate

What ion deficiency causes chlorosis?

Magnesium

Why do plants need nitrates ions?

Protein synthesis and growth

Why do plants need magnesium ions?

Make chlorophyll

What can infect plants?

Viruses

Bacteria

Fungi

Insects

Name a virus that can affect plants?

Tobacco mosaic

Name a fungus that can affect plants?

Rose black spot

Name an insect that can affect plants?

Aphids

What are the physical defence response to resist invasion of microorganisms?

Cellulose cell walls

Tough waxy cuticle on leaves

Layers of dead cells around stems which fall off

What the chemical defence response to resist invasion of microorganisms?

Antibacterial chemicals

Poisons to deter herbivores

What the mechanical defence response to resist invasion of microorganisms?

Thorns and hairs deter animals

Leaves which droop or curl when touched

Mimicry to trick animals