Topic 3 - Infection and Response Flashcards
Name the 4 types of pathogen
- bacteria
- virus
- fungi
- protist
Describe bacteria
Bacteria are very small cells that multiply rapidly and produces toxins that damage your cells and tissues e.g salmonella
Describe viruses
They are not cells. They reproduce rapidly inside host cells (by replicating themselves) and damage the cell e.g flu
Describe fungi
They grow between cells and through tissues, causing disease e.g athletes foot
Describe protists
They are single-celled eukaryotes that live on or inside other organisms and can cause damage. They are transferred to the organ by a vector e.g a mosquito carrying malaria
Describe Salmonella
- bacteria
- symptoms = fever, cramps, vomitting
- treat = poultry vaccination, cook chicken thoroughly, antibiotics
Describe Gonorrhea
- bacteria
- symptoms = urinating pain, yellow discharge
- treat = antibiotics, using condoms
Describe Measles
- virus
- symptoms = fever, rash, red skin
- treat = vaccine, isolate infected people
Describe HIV / AIDS
- virus
- symptoms = mild flu-like
- treat = antiretroviral drugs, use condoms, don’t share needles
Describe tobacco mosaic virus
- virus
- symptoms = mosaic pattern + discolouration on leaves
- treat = none, prevent by pest control
Describe rose black spot
- fungi
- symptoms = purple/black spots on leaves - weakens plant, poor growth
- treat = remove + burn infected leaves, chemical fungicides
Describe malaria
- protist
- symptoms = fever, tiredness
- treat = bed nets, insecticides
Describe the three ways white blood cells attack pathogens
- engulfing them (phagocytosis) - surrounds and destoys pathogen
- produces antibodies - lymphocytes produce antibodies that attach onto the antigen on the pathogen, this flags the pathogens for phagocytes to ingest them
- produces antitoxins - neutralise the toxins produced by pathogens
Pros and cons of vaccination
Pros:
- controls the spread of diseases and can eradicate them
- reduces epidemics
Cons:
- don’t always work
- can be side effects
Describe how vaccines work
- vaccines are small amounts of dead pathogens
- WBC detect the pathogens and produce specific antibodies
- a few of the antibodies stay in the blood once the pathogen is destroyed (called B memory cells)
- if you meet the pathogen again, the memory cells will produces antibodies very quickly
What is the difference between antiseptics and antibiotics?
Antiseptics kill microorganisms in the environment. Antibiotics kill bacteria (not viruses) in the body.
What is antibiotic resistance?
When strains of bacteria become resistant to antibiotics - meaning antibiotics will stop working
What plant does aspirin come from?
Willow tree
What plant does digitalis come from?
foxgloves
Describe painkillers
Painkillers are drugs that relieve pain but they don’t tackle the cause of the disease or kill pathogens - they just help the symptoms
Why is it difficult to develop medicines against viruses?
Viruses reproduce inside the cell so it is difficult to destroy the virus without damaging the cell
What are the four stages of drug testing?
- tested on human cells and tissues in the lab
- tested on live animals
- tested on a small group of healthy volunteers
- tested on a larger group of people with the condition
Why are mice often tested on?
- small and easy to look after
- mammal (like humans)
- not dangerous to handle
- not endangered
What three criteria are they testing for on animals?
- efficacy - if it works
- toxicity - if it’s harmful
- dosage - how much should be used
What does blind and double-blind trials mean?
Blind trials are when the patient doesn’t know whether they have the real drug or the placebo. Double-blind trials are when neither patient nor a doctor knows who has placebos or real drugs. This prevents bias
What is a placebo?
A drug that has no effect and is used to see if the drug only works because of the placebo effect
Define monoclonal antibodies
identical copies of one type of antibody
Describe how monoclonal antibodies are produced
- mouse gets vaccinated to produce specific antibodies
- lymphocytes are collected from mouse spleen
- WBC are mixed with myeloma to produce antibodies faster
- they create a hybridoma cell + screen to check
- clone and collect the antibodies
What are the uses of monoclonal antibodies?
- they trigger the immune system to recognise, attack and destroy cancer cells
- they block receptors on cancer cells so the cells stop growing and dividing
- carry toxic drugs or chemicals without harming cells in the body (drug is attached and released when it binds to target cell)
- used in hospitals/labs to monitor levels of chemicals in blood
- pregnancy tests
Describe how monoclonal antibodies are used in pregnancy tests
- HCG is a hormone found in pregnant women
- mobile antibodies attach to the HCG and move up the stick
- fixed antibodies attach to mobile antibodies if HCG present (+dye released)
- extra antibodies move up and attach to fixed antibodies + dye released to show it works
What are some signs of plant disease?
- stunted growth
- discolouration of/spots on leaves
- insects/pests
- areas of decay
- growths
- malformed stems/leaves
Plant diseases can be indentified by …
- gardening manuals and websites
- testing the plant in a lab
- test kits using monoclonal antibodies
Explain how a deficiency of magnesium could cause yellow leaves and stunted growth
Magnesium is need for chlorophyll so there would be less chloropyhll (not green) which means less light absorbed which means less photosynthesis which means less glucose which means less proteins (less growth).
What are physical defences of plants?
Physical barriers that protect the plant. Plants often have a waxy cuticle and cell walls made from cellulose, which provides a barrier
What are chemical defences of plants?
Plant can produce antibacterial chemicals which kill bacteria (mint oils) or secrete toxins to hurt insects or animals (foxgloves)
What are mechanical defences of plants?
Similar to physical defences but larger. They could have thorns or hairs or leaves that droop when stuff touches it to deter animals. Some plants mimic other organisms e.g the passion flower has yellow spots that look like butterfly eggs to stop butterflies laying their eggs there.
