B3: Infection and Response

Define pathogen

Microorganisms that enter the body and cause disease

T or F: Pathogens cause communicable diseases?

T

What are the 4 types of pathogen?

Bacteria

Viruses

Fungi

Protists

How do bacteria make us feel ill?

They release toxins inside the body that damage cells

Where do viruses reproduce inside the body?

Inside host cells

How do viruses make us feel ill?

They reproduce rapidly inside host cells until the cell bursts. The cell damage makes us feel ill

Are protists eukaryotes or prokaryotes?

Eukaryotes

What are parasites?

An organism that lives on or inside a host and takes the host's nutrients and energy, causing it damage

How do fungi cause disease?

They hypae penetrates human skin or surfaces of plants and causes disease

What are the 3 ways pathogens can be spread?

Water

Air

Direct contact

What type of pathogen is Measles?

Viral

How is measles spread?

Droplets from an infected person's sneeze or cough

What are the symptoms of measles?

Fever and red skin rash

What are 2 diseases that measles can sometimes lead to?

Pneumonia (lung infection)

Encephalitis (brain inflammation)

What type of pathogen is HIV?

Viral

How is HIV spread?

By sexual contact or exchanging bodily fluids, eg,. by sharing needles

What are the INITIAL symptoms of HIV?

Flu-like symptoms

What happens after the person stops feeling the initial symptoms of HIV?

They don't feel any symptoms for many years

What drugs can be used to control HIV after initial symptoms have passed?

Antiretroviral drugs

What is the name given to HIV when it attacks the body's immune system so it can't cope with other infections?

AIDS (late stage HIV)

What does HIV stand for?

Human Immunodefiency Virus

What type of pathogen is tobacco mosaic virus?

Viral

What is the main symptom of TMV?

A mosaic pattern on plant leaves, causing discolouration

What affect does leaf discolouration have on a plant?

The plant cannot absorb light for photosynthesis, so it cannot grow as well

What type of disease is rose black spot?

Fungal

What are the symptoms of rose black spot?

Purple/black spots on leaves.

Yellow leaves that drop off

What 2 ways does rose black spot spread?

Water or wind

Give 2 ways rose black spot can be treated.

Fungicides

Stripping and burning the leaves

What type of disease is malaria?

Protist

How is malaria spread?

By mosquitoes that act as vectors

What are the symptoms of malaria?

Repeating episodes of fever that can be fatal

How can people be protected from malaria?

Insecticides and mosquito nets

What type of disease is salmonella?

Bacterial

What illness does salmonella cause?

Food poisoning

What are the symptoms of salmonella (food poisoning)?

Vomiting, diarrhoea, stomach cramps and fever

How do people get salmonella?

Eating contaminated or undercooked food

What type of pathogen is Gonorrhoea?

Bacterial

What are the symptoms of gonorrhoea?

Pain when urinating

Thick yellow/green discharge from the penis or vagina

How can gonorrhoea be treated?

Antibiotics

How can the spread of gonorrhoea be reduced?

Use barrier methods of contraception like condoms

What 4 things can we do to reduce/prevent the spread of disease?

Being hygenic

Destroying vectors

Isolating infected people

Vaccination

How does the skin stop pathogens from entering the body?

Acts as a physical barrier to pathogens and secretes antimicrobial substances

How does hair and mucus in the nose stop pathogens from entering the body?What

They trap pathogens so they can be removed when you sneeze/blow your nose

How do the trachea and bronchi stop pathogens from entering the body?

They secrete mucus to trap pathogens, and cilia (small hairs) waft it back up to the throat where it can be swallowed

How does the stomach kill pathogens that enter the body?

It produces hydrochloric acid to kill any pathogens that make it into the body

What system in the body defends against infection?

Immune System

What happens in phagocytosis?

White blood cells engulf pathogens and destroy them

What is the name of the unique molecule found on the surface of every pathogen?

Antigen

What do white blood cells produce when they find a foreign antigen (pathogen)?

Antibodies

What is the role of antibodies?

Lock onto foreign antigens (pathogens) so they can be found and destroyed by other white blood cells

What can white blood cells produce to counteract toxins produced by invading bacteria?

Antitoxins

What is injected during a vaccination?

A dead or inactive form of a pathogen

What does a vaccination stimulate the immune system to do?

Produce antibodies and memory cells that will quickly repond when the stronger active pathogen invades the body

What does a vaccine stimulate the immue system to do?

Memory cells are produced, so when the alive, full strength pathogen invades, antibodies can be produced quickly to kill it before you get really ill

What is an advantage of vaccination?

Vaccines have helped control lots of communicable diseases that were once common is the UK

How can vaccines help prevent epidemics?

If most of the population is vaccinated, there are less people to pass it on to

What are 2 disadvantages of vaccines?

Sometimes they dont work

You could have a bad reaction to the vaccine

Define painkiller.

A drug that relieves the symptoms of a disease but does not destroy the pathogen

What do antibiotics do?

They kill (or prevent the growth of) bacteria without damaging healthy body cells

Why do antibiotics not kill viruses?

Viruses reproduce inside your own body cells, so they are not accessible to the antibiotic without damaging your healthy body cells

What plant does aspirin come from?

Willow

What antibiotic comes from foxgloves?

Digitalis

Who discovered penicillin?

Alexander Fleming

What are drugs tested on during the first preclinical trial?

Human cells and tissues in a lab

What are drugs tested on during the second preclinical trial?

Live animals

What does the secon preclinical trial test for?

Efficacy and toxicity

What is the drug tested on in clinical trials?

Humans

What is efficacy?

How effective the drug is at treating the disease

What is toxicity?

Whether the drug has any side effects and how harmful it is

What is dosage?

How much of the drug needs to be given

What is a placebo?

A substance that mimics the drug being tested but does not do anything and contains no active medication

What is a double blind trial?

A trial in which neither the patient nor the doctor knows who has been given the placebo and who has been given the active medication

What do all new results have to go through before they can be published?

Peer review

What does peer review help avoid?

Bias and false claims

What type of white blood cell produces monoclonal antibodies?

B-lymphocytes

T or F: Monoclonal antibodies are identical and will target only 1 specifc antigen?

T

What are B-lymphocytes fused wirth?

Tumour cells

What does a fused b-lymphocyte and tumour cell form?

A hybridoma

What happens to hybridoma cells to get monoclonal antibodies?

They are cloned lots of times to get lots of identical cells

What is the hormone found in the urine of pregnant women?

HCG

What are monoclonal antibodies attached to in pregnancy test strips?

Blue dye beads

What happeens inside the pregnancy test stick if you are pregnant?

The HCG binds to the antibodies on the blue beads

The urine moves up the stick, carrying the beads

The beads then bind to antibodies on the strip, turning it blue

What happpen inside the pregnancy test stick if you are not pregnant?

The urine carries the blue beads up the strip, but as there is no hormone with the blue beads, it doesnt stick to the antibodies on the strip, so the strip doesnt turn blue

What uniqque antigens do cancer cells have on their surfacw?

Tumor markers

Why are monoclonal antibodies better for treating cancer then chemotherapy and radiotherapy?

They don't damage healthy cells, only the cancer cells

What are monoclonal antibodies not as widely used as scientists first thought they would be?

They cause more side effects than they thought they would.

What are the 3 ions plants need to grow healthily?

Magnesium

Nitrate

Potassium

What are nitrate ions needed for?

Making proteins

What are magnesium ions needed for?

Producing chlorophyll

What are potassium ions needed for?

Production of flowers and fruit

What are 3 symptoms of ion deficiency?

Stunted growth

Leaf discolouration

Leaf loss

What are 5 signs a plant has a disease?

Stunted growth

Leaf discolouration

Patches of decay

Abnorrmal growths / lumps

Malformed stems/leaves

Give 3 ways plant diseases can be identified.

Gardening manual

Lab testing

Monoclonal antibodies testing kit

What are the 3 types of plant defences?

Physical

Chemical

Mechanical

Give 3 examples of physical plant defences.

Waxy cuticle

Cellulose cell wall

Layers of dead cells (eg. bark)

Give 3 examples of chemical plant defences.

Some plants produce antibacterial chemicals

Some plant produce poisons

Give 3 examples of mechanical plant defences.

Thorns and hairs

Leaves that droop or curl when touched

Mimicry