B3 - Infection and response Flashcards
What is the difference and similarities between a virus and bacteria ( 5 marks)
Virus - A lot smaller than bacteria
Virus lives inside cell and replicates themselves then bursts - releasing new viruses
Cell damage makes u feel ill
Bacteria - Make you feel ill by producing toxins that damage cells and tissues - outside cell
Both reproduce rapidly
What are protists and how can they make someone feel ill
Single-celled eukaryotes
Some protists are parasites - live on or inside other organisms and can cause damage
What is a vector
Organism that carries a protist but doesn’t get the disease itself
How do fungi make someone feel ill ( 2 marks)
Grow and penetrate human skin and the surface of plants causing diseases
How can pathogens spread (3 marks)
Water - drinking or bathing in dirty water
Air - breathed in - sneeze or cough
Direct contact - touching contaiminated surfaces
Measles:
What is it
How does it spread
Symptoms
Precaution against it
Virus
Droplets from an infected person’s sneeze or cough
Fever, red skin rash
Vaccination as a child
What is late stage HIV/AIDS
Body’s immune system is badly damaged and can’t cope with other infections or cancer
HIV:
What is it/happens
How does it spread
Symptoms
Treatment
Virus
Virus attacks immune cells
Sexual contact/exchange in bodily fluids - when drug users share needles
Flu-like symptoms
Antiretroviral drugs - stops virus replicating in the body
Salmonella:
What is it/happens
How does it spread
Symptoms
Treatment
Bacteria
Bacteria producing toxins
Fever, cramp, vomiting, diarrhoea
Food prepared in unhygienic conditions or not cooked properly
Improve food hygiene, wash hands, cook food thoroughly
UK - most poultry are vaccinated against salmonella
Malaria:
What is it/happens
How does it spread
Symptoms
Treatment
Caused by a protist
Part of malarial protist’s life cycle takes place inside mosquito
By vector (mosquito)
Prevent breeding of mosquitoes/use mosquito nets to avoid being bitten
Recurrent fever
Name the parts of our defence system and their function (6 marks)
Nose hairs - trap particles that contain pathogens
Trachea/Bronchi - release mucus to trap pathogens
Cillia - move mucus up to the throat to be swallowed
Stomach - produces hcl - kills most indigested pathogens
Skin - stops pathogen getting in
Rose black spot:
What is it/happens
How does it spread
Symptoms
Treatment
Fungus
Causes purple or black spots to develop on leaves of rose plants - leaves turn yellow then drop off
Less photosynthesis can happen - plant doesn’t grow very well
Spreads through environment in water or wind
Fungicides/removing affected leaves and destroying them
TMV:
What is it/happens
How does it spread
Symptoms
Treatment
Virus
Affects many species of plant e.g tomatoes
Causes mosaic pattern on leaves of plant - part of the leaves become discoloured
Discolouration means plant carries out less photosynthesis
Contaminated surfaces/ seed transmission
Gonorrhoea:
What is it/happens
How does it spread
Symptoms
Treatment
Bacteria
Sexual contact
Pain in urination/thick yellow or green discharge from genitals
Antibiotics - usage of barrier methods of contraception
Describe four ways the spread of disease can generally be reduced/prevented
Being hygienic - washing hands thoroughly
Destroying vectors - can no longer breed
Isolating infected individuals - prevents them from passing it on to someone else
Vaccination - Can’t develop infection and then pass it on
Describe the process of phagocytosis
Phagocytes engulf the pathogens and digest them
Antibodies are made by the body that has a specific shape to the antigen
Antitoxin used to neutralise toxins produced by bacteria
What is vaccination
Small amounts of dead or inactive form of the pathogen injected into the body - grow immunity
What are the pros and cons of vaccination (3 marks)
Pros:
helped control lots of communicable diseases that were common in the UK
Big outbreaks of disease - epidemics - can be prevented if a large percentage of the population is vaccinated
Cons:
Vaccines don’t always work - sometimes do not give immunity
You can have a bad reaction to a vaccine
What happens when you are first infected by a pathogen (vaccine)
What happens when you are re-infected by the same pathogen
White blood cells detect pathogen in the vaccine, antibodies are released into the blood
White blood cells produce antibodies quicker, so you do not become ill
What is a painkiller
Drug that are used to treat the symptoms of a disease, they do not kill pathogens
What does antibiotic mean
Drug that kills bacteria but does not work on viruses
What is aspirin and what was it developed from
Painkiller and lower - willow bark
What is digitalis and what was it developed from
A heart drug - foxglove plant
What is penicillin and what was it developed from
Antibiotic - mould
Describe and explain the three main stages in drug testing ( 6 marks)
Preclinical testing -Drug tested on human cells and tissues in the lab
Preclinical testing - drug tested on live animals - efficacy and toxicity and dosage (basically all 3 fr)
Clinical trial - drug tested on healthy volunteers - makes sure it does not have any harmful side effects when the body is working normally
At the start of the trial, a very low dose of the drug is given, and this gradually increases
If the results of the tests on healthy volunteers are good, the drug can be tested on people suffering from the illness - optimum dose is found
What is optimum dosage
Most effective and has few side effects
Describe the placebo trial
Patients are randomly put into two groups - one given the new drug, other given placebo - doctor can see the actual difference the drug makes
Describe and explain the double blind trial
Neither the patient nor doctor knows whether they are giving/receiving real drug or placebo until results have been gathered
Why do clinical trials of a new drug begin with healthy volunteers
Make sure the drug doesn’t have any harmful side effects when the body is working normally
Why must the results from drug testing be assessed by peer review
To help prevent false claims about the results
Describe four ways the spread of disease can generally be reduced/prevented
Being hygienic - washing hands thoroughly
Destroying vectors - can no longer breed
Isolating infected individuals - prevents them from passing it on to someone else
Vaccination - Can’t develop infection and then pass it on
