Paper 1 - infection and response

What are pathogens

Microorganisms that cause infectious disease

What are the 4 types of pathogen

Bacteria, viruses protists, fungi

How do bacteria make you feel ill

They produce toxins that damage your cells and tissues

Are bacteria cells or not

Cells

Are viruses cells or not

Not cells

What is a shared property of bacteria and viruses

They both reproduce rapidly inside your body

How do viruses cause cell damage

They live and reproduce inside cells, which usually means that the cell will burst, releasing all the new viruses

Are protists eukaryotes or prokaryotes

Eukaryotes

How can protists be harmful

• Some are parasites, which live on or inside other organisms and can cause them damage.

• Often transferred to the organism by a vector

Are most protists unicellular or multicellular

Unicellular

How do fungi cause disease

• some have a body made up of hyphae

• These hyphae can grow and penetrate human skin and surfaces of plants

How can fungal diseases be spread

The hyphae can produce spores, which can be spread to other plants and animals

Three ways pathogens can be spread

Water, air, direct contact

How does TMV affect the growth of plants

The monastic pattern of discolouration means that there is a lack of photosynthesis

What kind of disease is measles

Viral disease

How is measles spread

By droplets from an infected persons sneeze or cough

What are the symptoms of measles

Fever, red skin rash, can be fatal in serious cases

What can measles sometimes lead to

Pneumonia or inflammation of the brain

What is HIV

A virus spread by sexual contact or exchanging bodily fluids such as blood

How can people get HIV from needles

From sharing needles, e.g.when taking drugs

What are the initial symptoms of HIV

Flu like symptoms

What can HIV be controlled by

Antiretroviral drugs

What do antiretroviral drugs do

Stop the virus replicating in the body

What happens if HIV isn’t successfully controlled with antiretroviral drugs

The virus attacks the body’s immune cells

How do people get AIDS

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

What is rose black spot

A fungus that causes purple or black spots to develop on the leaves of rose plants, the leaves can then turn yellow and drop off

How does rose black spot affect the growth of plants

As photosynthesis is reduced

How is rose black spot spread

In the environment by water or wind

How can rose black spot be treated

Using fungicides or removing and destroying the affected leaves

What is salmonella

A type of bacteria that causes food poisoning

What are the symptoms of salmonella

Fever, abdominal cramps, vomiting, diarrhoea

How can you get salmonella

By bacteria ingested in food/ contamination , or on food prepared in unhygienic conditions

How does the UK help prevent the spread of salmonella

Most poultry is given a vaccination against salmonella, to control spread

What is gonorrhoea

A bacterial sexually transmitted disease

What are symptoms of gonorrhoea

Thick yellow or green discharge from vagina or penis and pain when urinating

How was gonorrhoea originally treated

Antibiotic penicillin

Why is gonorrhoea difficult to treat with penicillin now

Many strains of the bacteria have become resistant to the antibiotic

What is malaria caused by

A protist

Where does part of the malarial protists life cycle take place

Inside the mosquito, they are vectors. They pick up the malarial prosit when they feed on the blood of an infected animal

What happens when a mosquito bites another animal

It infects it by transferring the protist through its saliva into the animals blood

How can the spread of malaria be controlled

By preventing the vectors, mosquitos, from breeding, and humans can be protected from them using insecticides and mosquito nets

What are the symptoms of malaria

Recurring episodes of fever, can be fatal

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

How does skin defend the body against disease

Acts as a barrier to pathogens. Secretes antimicrobial substances to kill pathogens

How does the nose defend the body against disease

Hairs and mucus trap particles that could contain pathogens

How do the trachea and bronchi defend the body against disease

• Secrete mucus to trap pathogens.

• Lined with cilia which waft mucus up to the back of the throat where it can be swallowed

How does the stomach defend the body against disease

Produces hydrochloric acid which kills pathogens that make it to the stomach

What are the three ways white blood cells defend against pathogens

• Phagocytosis

• Antibody production

• Antitoxin production

  
  

What is phagocytosis

When white blood cells engulf, digest and destroy pathogens

What does every invading pathogen have on its surface

Antigens

How do antibodies work

• when some types of WBC find a foreign antigen, they rapidly produce proteins: antibodies

• These lock onto invading cells so they can be found and destroyed by other WBCs

What happens if a person is infected with the same pathogen again

The WBCs can produce antibodies more rapidly to kill it

What do you call white blood cells that produce antibodies

B-lymphocytes

What are antibodies specific to

One type of antigen

How do antitoxins work

They are produced to counteract toxins produced by the invading bacteria

What do vaccines contain

Small quantities of dead or inactive pathogens

How do vaccines work

• introduce small quantity of dead/inactive form of pathogen into the body to stimulate production of antibodies

• If the same pathogen enters the body the WBCs respond quickly to produce the correct antibodies, preventing infection

Pros of vaccination

• have he,pad control communicable diseases that were once common (like polio, measles)

• Epidemics can be prevented if a large percentage of the population is vaccinated

Cons of vaccination

• don’t always work, don’t always give immunity

• Sometimes have bad reactions; swelling, fever, seizures

What are antibiotics

Medicines, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body

How can bacteria become resistant to antibiotics

If bacteria mutates, sometimes the mutations cause them to be resistant

What do doctors do that slows down the rate of development of resistant strains of bacteria

Avoid over-prescribing antibiotics; only get them for something more serious than something like a sore throat

Tell you to finish whole course of antibiotics

What plant does the painkiller aspirin originate from

Willow

What plant does the heart drug digitalis originate from

Foxgloves

What mould did Fleming find that produced penicillin

Penicillium notatum

In preclinical testing, what are drugs tested on

Samples of human cells, tissues and live animals

What are the three main steps in developing drugs

• preclinical testing (laboratory)

• Clinical trials (human testing)

• Peer review

What happens in the preclinical trial

Drugs tested on cells, tissues and live animals to find out if the drug is toxic

What happens in phase 1 clinical trial

• Drug tested on healthy volunteers, very low doses

• Using healthy individuals = easy to see side effects

• Checks if drug is safe or has any side effects

What happens in phase 2 clinical trial

• Drug given to small number of patients with the disease

• Allows scientists to monitor efficacy of drug

What happens in phase 3 clinical trial

• If drug successful, given to larger group of patients with disease

• Scientists use this stage to get correct dosage

• Look out for any rare side affects that affect small numbers of people

What happens in the review and approve stage of developing drugs

• Results of trial must be reviewed by other scientists, peer review

• Prevents false claims, avoids bias and ensures valid conclusions

During all three phases of clinical trials, what are half the patients given

A placebo, tablet that doesn’t contain the drug

What’s a double blind trial

Both the patients and the doctors don’t know who is given the placebo

How are monoclonal antibodies produced

• a mouse is injected with a certain antigen so that it produces the specific antibodies needed

• Extract the b-lymphocytes from the mouse. These produce the antibodies specific to the antigen the mouse was injected with

• B-lymphocyte is fused with a tumour cell, which makes a