Topic #3: Infection and Response (Paper 1) Flashcards
What are the four types of disease causing pathogens?
Bacteria, Virus, Fungus, Protist
Give an example of a bacterial disease?
Salmonella: Causes; Fevers, Cramps, Vomiting and diarrhoea.
Gonorrhoea: STD. Causes; Painful burning feeling when urinating and produces thick yellow or green fluid (discharge) from the vagina or penis.
Give an example of a viral disease.
Measles. An air borne virus spread between small children. Causes: Fever and red rash like skin.
HIV/AIDS. STD. Immediatly after infection there can be flu like symptoms. after this there are usually no other symptoms. after time the virus attacks the immue system breaking it down. HIV (immunodefficiency virus) AIDS (Acquired immune deficiency syndrome)
there is still curently no cure to this.
Plant Disease: Tobacco Mosaic Virus
Give an example of a fungal disease.
Athlete’s foot. causes itching, flaking and blistering of the foot. tranmitted in communal areas where alot of people walk bare foot.
Plant Disease: Rose Black Spot
Give an example of a protist disease.
Malaria. symptoms include: fever, tiredness, vomiting and hedaches.
Plants: Aphids
What is the body’s first line of defence?
Skin- no openings for pathogens to get in and makes antimicrobial compounds that kill some pathogens.
Lysozymes in tears and saliva- antibacterial
Hairs and Cilia- prevent foreign bodies entering
Stomach acid- Acid destroys pathogens
What is the second line of defense?
Immune system
What happens in the immune system?
Antigens are detected by lymphocytes (a type of white blood cell), and the lymphocytes produce the correct antibodies to go and attach to those antigens and begin to engulf and destroy the pathogen (known as phagocytosis.)
How do bacteria work?
They enter the body and get into the bloodstream, dividing rapidly and producing toxins which is what make us feel ill
How do viruses work?
They enter the body and invade cells around them, replicate inside it then the cell bursts, releasing more of the virus to repeat the process,
How do fungi work?
They reproduce asexually, or sexually via spores
What is, and what does a vaccine do?
A vaccine is small dose of a dead or inactive pathogen. the body recognises it is a pathogen and destroys it, but the memory lymphocytes retain the antigens information for future reference so they can be ready faster upon the next infection, causing immunity
Difference between painkillers and antibiotics?
Painkillers reduce symptoms, antibiotics kill pathogen (bacteria only, antiviral for viruses)
Where do digitalis and aspirin come from?
Digitalis - foxglove
Aspirin - Willow
Describe the drug development process.
Drug is created and tested on animals to get some information
If deemed safe a small number of healthy people take it to determine efficacy, toxicity and dosage - start with low doses
More people are then tried to find optimums
Double blind trials take place
What is a double blind trial?
A placebo (looks like drug but has no effect) is in offered to some patients but neither the doctor or patient know whether it is real or not
How do we create monoclonal antibodies?
Stimulate mouse spleen cells to produce a desired antibody, then fuse it with a tumour cell to form a hybridoma which keeps replicating to get lots of a particular antibody.
What can monoclonal antibodies be used for?
Pregnancy Tests
Hormone level measurement
Bonding to dyes
Treating diseases
Why are monoclonal antibodies not used widespread yet?
Lots of side effects are caused
Expensive
Can damage body cells
However they are:
Useful for a range of diseases
Cheaper than drug development
Bindable to specific cells
What are plant disease symptoms?
Discolouring of leaves Stunted growth Pests Rot Unnatural growths Malformed leaves/stems
What causes chlorosis?
Magnesium deficiency
What is caused by nitrate deficiency?
Stunted growth - nitrate ions needed for protein synthesis, auxins for growth not made
What do auxins do?
They encourage growth
What mechanical adaptions have plants undergone to prevent disease?
Thorns to repel predators
Drooping leaves to shake off aphids
What physical changes have they made?
Layer of dead cells (eg. bark) that shed, taking pathogens with them
Cell walls
Leaf cuticles
