Topic 3- infection and response

What is the process of producing monoclonal antibodies

Mouse injected with chosen antigen, mouse lymphocytes are stimulated to make a particular antibody, B lymphocytes are taken from mouse, fast dividing tumour cells fused with B lymphocytes to form a hybridoma which can produce antibodies and divide rapidly by mitosis, a single hybridoma cell producing antibody wanted is selected, allow this hybridoma cell to divide by mitosis to form a clone of identical hybridoma cells that all produce the same antibody which can then be collected and purified

Why are the b lymphocytes fused with tumor cells

B lymphocytes can’t divide by mitosis

Where are monoclonal antibodies produced

In a laboratory

What are monoclonal antibodies

Antibodies from a single clone of cells

What are antibodies

Small proteins produced by our B lymphocytes that bind onto antigens

What is an antigen

A specific shaped molecule found on the surface of a pathogen that the immune system recognises as foreign and triggers an immune response

A monoclonal antibody always…

…binds to one specific thing

True or false: you can make monoclonal antibodies that bind to anything you want

True

What can you make monoclonal antibodies bind to

Particular protein/ cell with our body or harmful pathogen/chemical

What can you attach to the bottom of antibodies

Drugs, fluorescent proteins or radioactive material

How can you use monoclonal antibodies to treat cancer

Cancer cells have antigens (tumour markers) on their cell membranes not found on normal body cells. In a lab monoclonal antibodies can be made that bind to these tumour markers. Anti cancer drug can be attached to these monoclonal antibodies. The antibodies target specific cells as they only bind to tumour markers. The drug kills the cancer cells without killing normal body cells nearby

What type of anti cancer drug can be attached to the monoclonal antibodies when treating cancer

Radioactive substances, a toxic drug or chemical which stops cancer cells growing and dividing

What are the advantages of pregnancy tests

Quick, cheap, a reliable way of finding out if a woman’s pregnant

Describe structure of pregnancy tests

On the test strip there are lots of fixed monoclonal antibodies specific to HCG. The part you were on contains blue beads covered in the same HCG specific monoclonal antibodies that are free to move around.

How does a pregnancy test work if your not pregnant.

Urine will wash the unfixed beads along the test strip flowing right over the fixed antibodies on the other part. The test strip won’t turn blue as there’s nothing to stick the blue beads onto the test strip

How does a pregnancy test work if you’re pregnant

The HCG in urine will bind to antibodies on the blue beads so when the blue beads flow over the test strip the HCG they’re carrying binds to the fixed antibodies causing the beads to get stuck in place turning it blue

What is the use of a control window in a pregnancy test

Shows if the test has worked correctly

How does the control window in a pregnancy test work

Control window contains antibodies to the antibodies attached to the blue beads. This means that once the blue beads reach the control window the antibodies attached to them will bind to the antibodies stuck to the control window. Control window should go blue regardless of the results of the pregnancy test

How can you use monoclonal antibodies to locate specific molecules

Monoclonal antibodies are made that will bind to the specific molecules you’re looking for. Antibodies are then bound to a fluorescent dye. If molecules are present in sample being analysed the monoclonal antibodies will attach to them and they can be detected using the dye

What are the disadvantages of using monoclonal antibodies

Can cause fever, vomiting and low blood pressure

How can plants get diseases

Can be infected by viral, bacterial and fungal pathogens, larger organisms or can get deficiency diseases from a lack of essential mineral ions

What are some common symptoms of plant diseases

Stunted growth, spots on leaves, patches of decay, abnormal growths, malformed stems or leaves and discolouration

How can you identify plant diseases

Looking up signs in a gardening manual/ website, taking infected plant to a lab where scientists can identify the pathogen, using test kits that identify the pathogen using monoclonal antibodies

What are examples of insects that can damage plants

Aphids, spider mites

What are some physical plant defences

Waxy cuticle- provides a barrier to stop pathogens entering

Cell walls made from cellulose- form a physical barrier against pathogens that make it past the waxy cuticle

Layers of dead cells around stems- act as a barrier to stop pathogens entering

What are some chemical plant defences

Production of antibacterial chemicals which kill bacteria eg mint plant

Production of poisons which can deter herbivores eg tobacco plants

What are some mechanical plant defences

Thorns and hairs- stop animals form touching and eating them

Leaves that droop or curl when something touches them- prevent themselves being eaten by knocking insects off themselves and moving away from things

Mimicking other organisms eg passion flower has bright yellow spots on leaves which look like butterfly eggs and so stop other butterflies laying their eggs there

Where did aspirin originate from

A chemical found in willow

Where did digitalis originate from

A chemical found in foxgloves

Where did penicillin originate from

Penicillium notatum

What are the three main stages in drug testing

Preclinical testing on human cells and tissues, preclinical testing on live animals, clinical testing on human volunteers

Why do we drug test

To make sure drug is safe, effective and to find out the dosage

what is the disadvantage of preclinical trials on cells and tissues

Doesn’t tell us the effect on a particular organ or entire organism and can’t be used to test drugs that affect whole or multiple body systems

What is being tested in preclinical trials on live animals

Testing the efficacy, toxicity and best dosage of the drug

Why is a low dosage of the drug being tested given to healthy volunteers

To make sure there’s no harmful side effects when the body is working normally

What happens to the dosage of the drug during clinical trials on healthy volunteers

it is slowly increased to find maximum dosage we can give before we start to get side effects

What happens to the dosage of the drug during clinical trials on ill volunteers

It slowly increases so optimum dose can be found

What is optimum dosage

The dose of the drug that is most effective and has few side effects

How can you make the clinical trials fair

Blind trials and using a placebo

What is a placebo

A substance like the real drug that doesn’t do anything

What is the difference between blind and double blind trials

Blind trials is when patient doesn’t know if they’re receiving the drug or placebo, double blind trials is when both patient and doctor knows until all results are gathered

Why are double blind trials done

So doctors monitoring patients aren’t subconsciously influenced by their own knowledge

What are painkillers

Drugs that relieve pain/ symptoms but don’t help cure the problem

What are antibiotics

drugs that kill or prevent growth of bacteria causing the problem without killing your own body cells

Why do antibiotics not work on viruses

Antibiotics are made specifically to interfere with bacteria, viruses reproduce using your own body cells making it difficult to develop a drug to destroy the virus without destroying the body’s cells

Describe the process of antibiotic resistance

Bacteria can develop mutations which changes their characteristics. If you have an infection some of the bacteria might be resistant to antibiotics so when you treat infection only non resistant bacteria will be killed. The individual resistant bacteria will survive reproduce and the population of the resistant strain will increase

How can the development of antibiotic resistance be slowed down

Doctors avoid overprescription of antibiotics

What is a superbug

A bacteria resistant to lots of types of antibiotics eg MRSA

What is a vaccination/ how does it work

Involve injecting small amounts of dead or inactive pathogens. These carry antigens which cause your WBCs to produce antibodies to attack them. If live pathogens of same type appear later the WBCs can mass produce antibodies to kill pathogen making the vaccinated person immune to it.

What are the pros of vaccinations

Helped control lots of common infectious diseases and prevents epidemics if a large percentage of the population is vaccinated

What are the cons of vaccinations

Don’t always work and can sometimes have a bad reaction to a vaccine

What is meant by the term “herd immunity”

If a large percentage of a population is vaccinated against a pathogen the pathogen won’t have any people to spread it to

What are some examples of a bad reaction to a vaccination

Swelling, fever, seizures

How does the skin protect the body from pathogens

Acts as a physical barrier to pathogens, secretes antimicrobial substances which kill pathogens

How does the hairs and mucus in your nose protect the body from pathogens

Trap particles that could contain pathogens

How does the trachea and bronchi protect the body from pathogens

Lined with cilia (hair like structures) which waft the mucus up to the back of the throat where it can be swallowed

How does the stomach protect the body from pathogens

Produces hydrochloric acid which kills pathogens that make it that far from the mouth

What are the three ways white blood cells help to defend the body against disease

Phagocytosis, producing antibodies, producing antitoxins

What is phagocytosis

When white blood cells engulf foreign cells

How do antibodies work

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

The antibodies produced are…

…specific to that type of antigen

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

WBCs will rapidly produce the antibodies to kill it

What are bacteria

Single celled organisms that can reproduce by themselves and are 100x smaller than human cells

What is salmonella

A type of bacteria that causes food poisoning

What are the symptoms of salmonella

Fever, stomach cramps, vomiting and diarrhoea

How can you get salmonella

By eating chicken that caught the disease while it was alive, eating food that’s been contaminated by being prepared in unhygienic conditions

How is salmonella controlled

Most poultry in UK are given a vaccination against salmonella

What is gonorrhoea

A sexually transmitted disease caused by bacteria

How is gonorrhoea spread

Unprotected sex

What are the symptoms of gonorrhoea

Pain when urinating, thick yellow or green discharge from vagina or penis

Why is gonorrhoea not easily treated with penicillin anymore

Strains of bacteria have become resistant to it

How can you prevent the spread of gonorrhoea

Using other antibiotics and contraception barrier methods eg condom

How can you reduce and prevent the spread of disease

Being hygienic, destroying vectors, isolating infected individuals, vaccination

How does destroying vectors prevent the spread of disease

Vectors spread the disease to humans and so by destroying the vectors, the disease cannot be passed on

What is an example of a fungal disease in plants

Rose black spot

What is rose black spot

A fungus that causes purple or black spots to develop on the leaves of rose plants

Why does a plant being infected with rose black spots affect the growth of a plant

The leaves can turn yellow and drop off which means less photosynthesis can happen so the plant doesn’t grow very well

How is rose black spots spread

In water or by wind

How can rose black spot be treated

Using fungicides and by stripping plant of its affected leaves and destroying them

What is malaria

A disease caused by a protist that causes repeating episodes of fever and can be fatal

Where does part of the malarial protist’s life take place

Inside a mosquito

how is malaria spread

When mosquitos pick up the malarial protist when feeding on an infected animal it infects another animal by inserting the protist into the animals blood vessels when feeding on them

How can the spread of malaria be controlled

Stopping mosquitoes from breeding, protecting people from mosquito bites

What is measles

A viral disease spread through the droplets of an infected persons sneeze or cough

What are the symptoms of measles

Red skin rash, fever

What can measles sometimes lead to

Pneumonia (lung infection), encephalitis (brain infection)

What is HIV

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

How does HIV attack the body

Virus attacks the immune cells, if immune system is badly damaged it can’t cope with other infections or cancers (this stage is known as late stage HIV or AIDS)

What does HIV initially cause

Flu-like symptoms

How can HIV be controlled

Antiretroviral drugs

What is tobacco mosaic virus (TMV)

A virus that causes a mosaic pattern on the leaves o the plant, parts of the leaves become discoloured

How does TMV affect the growth of a plant

Discolouration means the plant can’t carry out photosynthesis as well so the growth is stunted

What is a pathogen

Microorganisms that enter the body and cause communicable diseases in plants and animals

What are the different types of pathogens

Bacteria, viruses, protists and fungi

What is bacteria

Very small cells which can reproduce rapidly inside your body

How can bacteria make you feel ill

By producing toxins that damage your cells and tissue

What is a virus

Tiny non living particles that live inside your cells and replicate themselves using cells machinery to produce many copies of themselves

Can viruses reproduce rapidly inside your body

Yes

How can viruses make you feel ill

Causing cell damage (bursting cell) when they reproduce