Topic 3: Infection and Response Flashcards
What is the definition of a pathogen?
Microorganisms that cause infectious disease and depend on host to provide conditions and nutrients needed to grow and reproduce
Name the four types of pathogen and how they are spread
Virus, Bacteria, Protists, Fungi
Infect plants and animals and spread by direct contact, water or air
Why are bacteria and viruses dangerous?
Can reproduce rapidly in body and produce toxins which damage tissues and makes us feel ill. These toxins cause symptoms of infection which include high temp. , nausea etc. Viruses also live and reproduce in cells, which cause cell damage
What is HIV short for?
Human Immunodeficiency Virus
What are the symptoms of HIV?
-Flu-like illness
-Enter lymph nodes and attack immune cells
-Can develop into AIDS in which body can no longer deal with infections or cancers
How is HIV spread?
-Exchange of body fluids (blood shared from needles)
-Sexual Contact with infected person
How can the spread of disease be reduced?
-Hygiene Measures
>Covering Mouth
>Washing Hands
-Destroying Vectors (Mosquitoes vector for malaria)
-Isolation of infected individuals
-Vaccination
How can HIV be prevented/treated?
-Don’t share needles
-Protection
-Antiretroviral Drugs
What is measles and what are the symptoms?
Viral disease which causes fever and red skin rash
How is measles spread?
-Contact with infected person
-Inhalation of droplets from coughs or sneezes
How can measles be prevented/treated?
-There is no treatment for measles
-Prevented with the MMR Vaccine (Measles, Mumps, Rubella)
Children are vaccinated early as can be fatal if complications arise
What is TMV and what does it affect?
-Tobacco Mosaic Virus
-Only affects plants
- Widespread plant pathogen affecting species including tomatoes
What are the symptoms of TMV?
- Distinct ‘mosaic’ pattern of discoloration on leaves
-Can’t photosynthesise
-Stunted Growth which may lead to death
How is TMV spread?
-Physical Contact with infected leaves/tools
How can TMV be prevented/treated?
-Prevent transmission
-Kill infected tissue/plants
-Disinfect tools between use
What are the symptoms of salmonella?
-Fever
-Abdominal Cramps
-Vomiting
-Diarrhoea
How is Salmonella spread?
-Bacteria is ingested in food due to being prepared in unhygienic conditions
How can Salmonella be prevented/treated?
-Check source of food
-Don’t eat raw/uncooked poultry
-Poultry are vaccinated against it to control spread
Explain why Malaria is special
-Classified as protist
-No pathogens are malaria but the pathogens which cause malaria belong to protists plasmodium
What are the symptoms of Malaria?
-Recurrent episodes of fever
-Cam be fatal
How can Malaria be spread?
-Female, Pregnant, Anopheles Mosquitoes which have previously bitten someone infected
How can Malaria be prevented/treated?
-Preventing vector (mosquito) from breeding
-Mosquito nets to avoid getting bitten
-Anti-malaria biotics
Describe the life cycle of Plasmodium
-Mosquito bites an infected person
-Gametes for plasmodium enter mosquito
-Plasmodium moves to mosquito’s salivary glands
-Mosquito bites another person
-Injects saliva and plasmodium enters bloodstream
-Plasmodium moves to liver and multiplies
-Moves back into blood and invades red blood cells
-Plasmodium produces gametes in red blood cell
-Bursts cell and gametes enter blood plasma
Non-Specific Defence Systems
Ways humans defends itself against entry of pathogens which include: Skin, Stomach acid, Nose, Trachea/Bronchi, Tears, Blood Clots
Phagocytosis Brief Description
If pathogen enters body, immune system tries to destroy pathogens with phagocytes which engulf and destroy pathogens. This can include inflammation or ingestion.
What are the two main types of drug?
Recreational and Medicinal Drugs
What are the two further sections of medicinal drugs?
Painkillers: Reduces pain, relieves symptoms, doesn’t kill pathogens, doesn’t heal
Examples include: Paracetamol, Ibuprofen, Aspirin, Morphine
Antibiotics: Kill bacteria without damaging animal cells, Don’t kill viruses
Examples include: Penicillin, Amoxycillin
How was penicillin discovered?
-Alexander Fleming
-Came from fungus penicillium
-Experiment with bacteria colonies on Petri Dish
-Penicillium grew on dish
-Killed bacteria on it
What are the natural origin of drugs (from plants):
Coffee- Caffeine
Cocoa, Tea, Cola- Theophylline
Poppy- Codeine
Tobacco- Nicotine
Mint- Menthol
Foxglove- Digitalin
Belladonna- Atropine
Yew- Taxol
Thyme- Thymol
What is the first stage of modern day drug development?
Synthesis/Extraction
> Identify active ingredient and have an idea of it being a drug
What is the second stage of modern day drug development?
Preclinical Testing
>Test on cell/tissues to see if drug works and how well it works e.g. toxicity
What is the third stage of modern day drug development?
Clinical Trials (Three Phases)
1) Test on healthy volunteers to look for side effects LOW DOSAGE ONLY
2) Test on patients to see strength/potence and side effects LOW DOSAGE ONLY
3) Test on patients with INCREASED dosage to see if it works, suitable dosage, side effects
What is the main focus of testing drugs?
1) Side effects / Toxicity
2) Efficacy
3) Dosage
What is a placebo?
Drug that has no effect to see difference, control group, COMPARISON
What is a double blind trial?
Neither the patient or doctors know who takes the placebo to prevent bias
What is peer-review?
When a study has been checked by other scientists in a different lab
What are the three types of white blood cell?
-Phagocytes
-B-Lymphocytes
-T-Lymphocytes
What is a T-Lymphocyte?
Recognise antigens and attack them directly or activate B-Lymphocytes
What is a B-Lymphocyte?
Produce antibodies and antitoxins
What is an antibody?
Special Y-Shaped proteins and bind to antigens on pathogens causing them to clump and be destroyed
Why are monoclonal antibodies used compared to normal white blood cell?
White blood cell can only divide if they don’t produce antibodies, they don’t divide as soon as it does
Characteristics of MCA
-Come from cells which have been cloned
-Produced and used over long periods of time and are lots of copies of a specific antibody
- Produced in lab
- Allows white blood cell to divide whilst producing antibodies
How is MCA produced?
1) Mouse injected with specific antigen to stimulate lymphocytes to make particular antibody
2) Extracted lymphocytes combine with particular cancerous tumour cell. Detergents are used to help break down cell membrane of both cells to help them fuse
3) Create hybridoma cell, which divides and makes antibodies
4) Single hybridoma cells are cloned to produce identical cell that produce same antibody
5) Large amounts of MCA collected and purified
What are MCA’s used for?
-Pregnancy Testing Kits
-Diagnostic Tool (HIV)
-Industrial production interferon (treats cancers)
-Specific drug delivery
How do pregnancy tests work?
Urine is placed onto strip and urine travels through paper to three zones: Reaction Zone, Test Zone and Control Zone
Describe the Reaction Zone of the pregnancy test
Mobilised antibodies attach/bind to hCG with a colour-reacting enzyme
Describe the Test Zone of the pregnancy test
Immobile antibodies bind to hCG antibodies and release dye from enzymes
Describe the Control Zone of the pregnancy test
Test for mobilised antibodies which didn’t bind to hCG to see if test was faulty and release dye from enzymes
How is MCA used for identification?
Antibodies attached to dye that will glow under UV light which helps with identification process
What are the three possible ways to treat cancer with MCA?
1) Monoclonal antibodies directly stimulate immune system to respond, attack and destroy cancer cell
2) MCA block receptors, preventing them from growing, dividing
3) MCA used to transport toxic drugs or radioactive substances which control growth of cell and attack them
What are some possible side effects of MCA?
-Chills or Fever
-Itchy Rashes
-Nausea
-Breathlessness/Wheezing
-Headaches
-Change in blood pressure
What are the factors to tell if a plant is unhealthy / diseased?
- Stunted Growth
- Spots on leaves
- Plant pests
- Decolouration
What is chlorosis?
Breakdown of chlorophyll due to lack of magnesium ions which cause yellow on leaves and affects photosynthesis
What are examples of mechanical plant defences?
- Thorns and hairs deter animals from eating or touching them
- Leaves which droop or curl when touched
- Mimicry to trick animals into not eating or laying eggs on leaves
What are examples of chemical plant defences?
- Production of anti-bacterial / fungal chemicals
- Poisons to deter herbivores
What are examples of physical plant defences?
- Cellulose cell walls
- Tough waxy cuticle on leaves
- Layer of dead cell around cell (bark) which fall off, taking pathogens with them
What is rose black spot?
- Fungal disease where purple or black spots develop on leaves, turn yellow and drop early
- Spread by water and wind
How is rose black spot treated?
- Using fungicides or removing infected leaves
