Infection and Response Flashcards
Pathogens
Bacteria or virus that can cause illness
How can pathogens be spread? [4]
- Direct contact
- Air
- Water
- Vector
Name the prevention methods for spread of infectious disease [4]
- Simple hygiene
- Destroying Vectors
- Isolating affected individuals ( cannot pass on )
- Vaccinating at-risk individuals
How do virus spread?
- Live and reproduce inside cell
2. Damage caused by bursting out of cell
What are the symptoms of measles? [2]
- Fever
2. Red skin rash
What type of pathogen is measles and how is it spread?
- Virus 2. Coughing or sneezing
How is measles prevented?
Vaccination
What type of pathogen is HIV and how is it spread? [3]
- Virus 2. Sexual contact
3. Exchange of bodily fluids, e.g. needles
How does HIV turn into AIDS?
- Virus enters the lymph node
2. Attacks immune cells
What is AIDS?
When the body’s immune system is damaged and so cannot fight other infections or cancers
How can AIDS be prevented?
Anti-viral drugs can only delay the process
How can bacteria cause damage? [2]
- reproduce rapidly 2. release toxins- damage tissues = cause illness
Salmonella
A type of food poisoning caused by bacteria
How is salmonella spread? [2]
- Bacteria present in uncooked food or food prepped in unhygienic condition
- These are ingested
What are the symptoms of Salmonella and why?
- Bacteria secrete toxins
2. They cause fever, abdominal cramps, vomiting and diarrhoea
How can the spread of salmonella be prevented?
- Treatment: Poultry vaccinated against salmonella
2. Prevention: Clean surface before cooking => ensure meat is cooked thoroughly
Gonorrhoea
A STD caused by bacteria
How is Gonorrhoea spread?
Sexual contact
What are the symptoms of Gonorrhoea? [2]
- Green/ yellow discharge from penis/vagina
2. Pain whilst urinating
How can Gonorrhoea be prevented/ treated?
- Penicillin used to be used=> resistant strains formed
- Now treats with antibiotics
- Prevented using condoms
Describe how Malaria is transmitted? [2]
- mosquito is the vector
2. When bitten, a person receives the protist
How can malaria be prevented/ treated?
- Kill vector (bug spray)
- Stop biting (mosquito nets)
- Antimalarial drugs (treat infection)
What type of disease is Rose Black Spot?
A fungal plant disease
How is RBS spread?
- When spores are carried plant to plant by air or water
2. Plant to plant on hands, clothing or tools
What are the symptoms of RBS? [3]
- Enlarged black patches on leaves
- Dropping leaves
- Small black lesions on stem
- Can lose ALL leaves if badly affected
How can RBS be prevented/ treated?
- Fungicide
2. Removing and destroying affected leaves
Non Specific Defenses
= First line defence
stops pathogens from entering body= general defences => not specific to fight against certain types of pathogens
What is the role of Cilia? [2]
- Creates a wave like motion
2. To push mucus away from lungs
What is the role of Tears? [2]
- Enzymes in tears
2. Destroy microorganisms
What is the role of the Nose? [2]
- Contains hairs and mucus
2. trap particles which may contain pathogens
What is the role of Sebaceous glands? [2]
- Produces sebum on the skin
2. Kills bacteria and fungi
What is the role of the glands in the stomach wall? [2]
- Produce hydrochloric acid
2. Which kills microorganisms
What are the two ways in which White blood cells defend the body from pathogens?
- Production of Antibodies
2. Phagocytosis
Describe Phagocytosis [4]
- Microorganisms enter the body
- White blood cells locate and engulf them
- They then ingest them and use enzymes to digest them
- The microorganisms are now destroyed
Describe the use of antibodies to destroy pathogen [4]
- Antigen are markers on surface of microorganisms
- White blood cells become sensitised and produce antibodies
- These Lock onto antigens
- This causes them to clump up allowing White blood cells to digest them
What is immunity? [2]
- If the same pathogen re-enters a body, White blood cells use their memory to quickly produce the correct specific antibodies
- This quick reaction prevents the person becoming ill again
What is a Vaccination? [2]
- Small quantities of dead/ inactive pathogens are injected into the body
- These stimulate White blood cells to create antibodies and develop immunity
What are Antibiotics?
Medicine that kill bacteria inside the body
What is MRSA?
A strain of bacteria resistant to antibiotics
How can doctors help reduce the rate at which resistant strains of bacteria form? [3]
Don’t prescribe:
- Unless it is really needed
- For non-serious infections
- For viral infections
- Completing the full course
Why must patients complete their courses of antibiotics?
To make sure that all bacteria is killed and that none survive to form resistant strains
Growing Bacteria method [9]
- Use a disinfectant to clean the work bench
WHY kills any microorganism - Sterilise petri dish
WHY kill any microorganism (bacteria) on it - Sterilise the inoculating loop by passing through the flame
WHY kills any microorganism (bacteria) on it - Keep a naked flame near the petri dish
- Open the lid of the petri dish slightly
WHY prevents entry of any microorganism from the air - Inoculate the agar with the bacteria- make streaks on the surface of the agar plate.
WHY allows bacteria to spread out and to grow in individual colonies OR evenly spread - Seal the lid of petri dish with sticky tape- oxygen can enter- promotes bacteria growth.
=> do not seal the whole dish with sticky tape
BECAUSE harmful anaerobic bacteria can grow - Store petri dish upside down
- Incubate at 25 WHY promotes growth of bacteria. WHY Higher temperature- risk of human pathogen
Why is there an increased demand for more drugs? [3]
- New painkillers=> treatment of symptoms
- Antiviral drugs=> kill viruses without damaging tissues
- New Antibiotics=> due to more resistant strains of bacteria
What does culture medium contain? [2]
- Carbohydrate as energy source
2. Nitrogen to make Protein
What conditions are required for bacteria to grow? [4]
- Warmth
- Oxygen
- Nutrient availability
- pH
Why are antibiotics ineffective against viruses? [2]
- Viruses live and reproduce inside cell
2. it’s difficult to produce medicine without damaging the own cells
Why don’t medicines like aspirin actually cure illness?
Because they do not kill the pathogens that are making you ill.
What is a placebo? [2]
- It looks like the drug
2. But does not contain any active ingredient
What is a double blind trial?
Neither the patient or the doctor know whether the patient is in the control group or not
What happens in the Pre- clinical trials? [3]
- Drugs are tested using computer models and skin cells grown using human stem cells .
- Drugs are tested on animal CELLS or TISSUES.
- To test for efficacy and side effects
What is Phase 1 of Trials? [2]
- Drug is tested on small groups of healthy volunteers
- Control variable (for example- same age, height etc. tailor it to the question)
- Testing for side effects
What is Phase 2 of Trials? [2]
- Test on LARGER (100-300) number of volunteers with disease
- Test for efficacy, change dosage and continue monitoring side effects
What is Phase 3 of Trials? [4]
- Large group of volunteers (with disease) = 2000-5000
- Placebo drug is given (give definition)
- Double blind trials are conducted
- Peer review of data - to prevent false claims
Herd Immunity
When a large proportion of the population is immune to a disease, it will be reduced and may disappear
How can Monoclonal Antibodies be created? [6]
- Antigen injected into mouse
- Mouse produces lymphocytes (NOT WBC) - produces antibodies specific to the antigen
- Spleen cells- produces lymphocytes are removed (as Lymphocytes do NOT divide)
- Spleen cells are fused with cancerous white blood cells calledmyeloma cellsto formhybridoma cellswhich divide uncontrollably
- Hybridoma cells divide (mitosis) = large quantities of monoclonal antibodies
- monoclonal antibodies = specific to original antigen
What are the 5 uses of Monoclonal antibodies?
- Pregnancy tests
- Diagnosis of disease
- Measuring and monitoring blood chemicals
- Researching cells
- Treating diseases such as Cancer
How can Monoclonal Antibodies be used in a Pregnancy test? [3]
- HCG hormone present in pregnant woman’s urine
- Monoclonal antibodies that bind to HCG hormone if it is present in the urine at end of stick
- When they urinate antibodies bind with antigen in hormone - produce colour change or show indication = pregnant
How can Monoclonal Antibodies be used to diagnose disease? [2]
- Monoclonal antibodies bind to antigen on cancer to diagnose presence of tumours
- Or antibodies carry markers and build up in an area
How can Monoclonal Antibodies be used to Treat diseases? [3]
- Direct use of MA for immune system to destroy cancer cells
- Block receptors on surface of cancer cells=> stop cell growth/ division
- Carry toxic drugs or radioactive substance=> stop cell growth/ division
How can Monoclonal Antibodies be used to measure and monitor Blood?
They measure hormones and chemicals in blood e.g illegal drugs or infections
How can Monoclonal Antibodies be used for cell research? [2]
- To identify specific molecules in a cell or tissue
2. (by binding to them with fluorescent dye)
What are the advantages of monoclonal antibodies? [3]
- Only bind to specific diseased/damaged cells
- They treat a wide range of conditions
- mouse-human hybrid cells reducing side effects (less chance of rejection)
What are the disadvantages of Monoclonal antibodies?’ [3]
- drug treatment carried around the body=> could affect healthy cells as well as cancer cells
- very expensive to develop
- Mouse cells=> more side effects= not widely used or successful in beginning
What are some signs of plant disease?
- Stunted growth
- Spots on leaves
- Areas of decay
- Malformed leaves/stem
- Discolorations
What are the symptoms of TMV? [3]
- Discoloration on leaves
- Brown spots on the surface of leave=> reduced chlorophyll=> less photosynthesis=>
- Stunted growth
How is TMV transmitted? [2]
- Through wounds after human handling/ contaminated equipment
- Virus contaminated seeds=> contaminated plants
How can TMV be treated or prevented? [4]
- No cure=> dig up and burn affected plants
- Practise good hygiene
- Remove decaying leaves from plant and soil
- Disinfect all gardening tools
What are Aphids and what do they do?
- Small insects also know as greenfly or blackfly
2. Feed on Phloem and take sugars away
What is stunted growth caused by?
A nitrate deficiency, as nitrate ions are required for protein synthesis
What is Chlorosis caused by?
Magnesium deficiency, as magnesium ions are needed to produce chlorophyll
What are the physical plant defences? [3]
- Cellulose cell walls = barrier => difficult for pathogens to penetrate
- tough waxy cuticle on leaves = barrier => difficult for pathogens to penetrate
- Thick bark= layers of dead cells => fall off taking pathogens with them
What are the chemical plant defences? [2]
- Antibacterial chemicals- kills bacteria
2. Poisons to deter
What are the mechanical adaptations of plants?
- Thorns and Hairs to deter = unpleasant and painful for herbivores to eat so avoided
- Leaves that droop when touched= difficult to feed, dislodges insects + frightens larger animals
- Mimicry= looks unhealthy to trick animals into not eating them + mimic butterfly eggs= butterflies do not lay eggs on them to avoid competition
What did Ignaz Semmelweis find? [7]
- Hungarian doctor who worked in 2 labour wards
- wards cleaned once a month.
- doctors didn’t wash hands and often wore filthy coats
- some medical students + doctors went from touching corpses to delivering babies without washing their hands
- high number of women who died after easy births – with very high temperatures and fever
- noted that 3 times the number of women were dying in teaching ward compared to midwives ward
- made all doctors wash their hands in chlorine water before examining the women and the death rate decreased
Skin - First line defence
- Skin produces antimicrobial secretion to destroy bacteria.
- platelets form blood clot, which dries to form a scab stopping pathogens getting in
