B3-infection and response Flashcards
pathogens
Pathogens are microorganisms that cause infectious disease.
Give 4 examples of pathogens.
Pathogens may be viruses, bacteria, protists or fungi.
what do pathogens do and how are they spread
They may infect plants or animals and can be spread by direct contact, by water or by air.
significance of bacteria and viruses
Bacteria and viruses may reproduce rapidly inside the body.
how do bacteria make us ill
Bacteria may produce poisons (toxins) that damage tissues and make us feel ill.
how do viruses make us ill
Viruses live and reproduce inside cells, causing cell damage.
what do bacteria damage
tissue
what do viruses damage
cells
what type of disease is measles
+symptoms
Measles is a viral disease showing symptoms of fever and a red skin rash.
measles symptoms
Measles is a viral disease showing symptoms of fever and a red skin rash.
risk of contracting measles
Measles is a serious illness that can be fatal if complications arise. For this reason most young children are vaccinated against measles.
why are most young people vaccinated against measles
Measles is a serious illness that can be fatal if complications arise. For this reason most young children are vaccinated against measles.
how is measles spread
The measles virus is spread by inhalation of droplets from sneezes and coughs.
what does hiv cause symptom wise
HIV initially causes a flu-like illness. Unless successfully controlled with antiretroviral drugs the virus attacks the body’s immune cells.
what happens in late stage hiv
Late stage HIV infection, or AIDS, occurs when the body’s immune system becomes so badly damaged it can no longer deal with other infections or cancers.
what causes aids
Late stage HIV infection, or AIDS, occurs when the body’s immune system becomes so badly damaged it can no longer deal with other infections or cancers.
how is hiv spread
HIV is spread by sexual contact or exchange of body fluids such as blood which occurs when drug users share needles.
what is tmv
Tobacco mosaic virus (TMV) is a widespread plant pathogen affecting many species of plants including tomatoes.
tmv symptoms
It gives a distinctive ‘mosaic’ pattern of discolouration on the leaves which affects the growth of the plant due to lack of photosynthesis.
how is salmonella spread
Salmonella food poisoning is spread by bacteria ingested in food, or on food prepared in unhygienic conditions.
what does tmv cause in plants
stunted growth
how is salmonella prevented in uk
In the UK, poultry are vaccinated against Salmonella to control the spread.
symptoms of salmonella
Fever, abdominal cramps, vomiting and diarrhoea are caused by the bacteria and the toxins they secrete.
what is gonorrhea
Gonorrhoea is a sexually transmitted disease (STD) with symptoms of a thick yellow or green discharge from the vagina or penis and pain on urinating.
symptoms of gonorrhea
Gonorrhoea is a sexually transmitted disease (STD) with symptoms of a thick yellow or green discharge from the vagina or penis and pain on urinating.
what causes gonorrhea
It is caused by a bacterium and was easily treated with the antibiotic penicillin until many resistant strains appeared. Gonorrhoea is spread by sexual contact.
what type of pathogen is gonorrhea
bacteria
how do we control spread of gonorrhea and or treat it
The spread can be controlled by treatment with antibiotics or the use of a barrier method of contraception such as a condom.
what is rose black spot
Rose black spot is a fungal disease where purple or black spots develop on leaves, which often turn yellow and drop early.
what type of pathogen is rose black spot
fungal
symptoms of rose black spot
Rose black spot is a fungal disease where purple or black spots develop on leaves, which often turn yellow and drop early.
what is the effect of rose black spot in plants
It affects the growth of the plant as photosynthesis is reduced.
how is rose black spot spread
It is spread in the environment by water or wind.
how is rose black spot treated
Rose black spot can be treated by using fungicides and/or removing and destroying the affected leaves.
what pathogen causes malaria and what specific type
The pathogens that cause malaria are protists. The malarial protist has a life cycle that includes the mosquito.
malaria symptoms
Malaria causes recurrent episodes of fever and can be fatal.
how do we control the spread of malaria
The spread of malaria is controlled by preventing the vectors, mosquitos, from breeding and by using mosquito nets to avoid being bitten.
what is vaccination
Vaccination involves introducing small quantities of dead or inactive forms of a pathogen into the body to stimulate the white blood cells to produce antibodies.
how do white blood cells prevent reinfection of the same pathogen
If the same pathogen re-enters the body the white blood cells respond quickly to produce the correct antibodies, preventing infection.
what are antibiotics and how do they work
Antibiotics, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body.
why are there a variety of antibiotics
It is important that specific bacteria should be treated by specific antibiotics.
one advantage and disadvantage of antibiotics
The use of antibiotics has greatly reduced deaths from infectious bacterial diseases. However, the emergence of strains resistant to antibiotics is of great concern.
when arent antibiotics effective
Antibiotics cannot kill viral pathogens.
what are painkillersused to treat
+not
Painkillers and other medicines are used to treat the symptoms of disease but do not kill pathogens.
why is it difficult to develop drugs against viruses
It is difficult to develop drugs that kill viruses without also damaging the body’s tissues.
how were drugs traditionally extracted
Traditionally drugs were extracted from plants and microorganisms.
origin of digitalis
The heart drug digitalis originates from foxgloves.
what is digitalis
a heart drug that originates from foxgloves
where does aspirin originate from
The painkiller aspirin originates from willow.
what is aspirin
a painkiller
where does penicillin originate from
Penicillin was discovered by Alexander Fleming from the Penicillium mould.
who discovered penicillin
alexander fleming
what is penicillin
an antibiotic
how are drugs extracted in modern times
Most new drugs are synthesised by chemists in the pharmaceutical industry. However, the starting point may still be a chemical extracted from a plant.
what must happen to all new drugs before being used commercially
New medical drugs have to be tested and trialled before being used to check that they are safe and effective.
what 3 things are drugs tested for
New drugs are extensively tested for toxicity, efficacy and dose.
what happens during preclinical testing
Preclinical testing is done in a laboratory using cells, tissues and live animals.
what happens in clinical trials
- Clinical trials use healthy volunteers and patients. Very low doses of the drug are given at the start of the clinical trial.
- If the drug is found to be safe, further clinical trials are carried out to find the optimum dose for the drug.
- In double blind trials, some patients are given a placebo. but neither participants nor researchers are aware who is in the control group
double blind trial
Both the patient and doctor do not know which drug is being administered. To avoid bias.
placebo
Placebo is a fake drug.
what are monoclonal antibodies produced from and why does it work
- Monoclonal antibodies are produced from a single clone of cells.
- The antibodies are specific to one binding site on one protein antigen and so are able to target a specific chemical or specific cells in the body.
how are monoclonal antibodies produced
- mouse injected with antigen
- mouse produces antibodies for antigen
- extract lymphocytes from mouse
- combine lymphocytes with tumour cells as they cannot divide by mitosis
- this produces a hybridoma cell
- the hybridoma cell divides to create a clone of identical hybridoma cells
how are hybridoma cells made
The lymphocytes are combined with a particular kind of tumour cell to make a cell called a hybridoma cell.
what do hybridoma cells do
The hybridoma cell can both divide and make the antibody.
what are hybridoma cells used for
Single hybridoma cells are cloned to produce many identical cells that all produce the same antibody. A large amount of the antibody can be collected and purified.
uses of monoclonal antibodies (3-4)
- for diagnosis such as in pregnancy tests.
- In laboratories to measure the levels of hormones and other chemicals in blood
- to detect pathogens
- In research to locate or identify specific molecules in a cell or tissue by binding to them with a fluorescent dye.
how can monoclonal antibodies treat cancer
for cancer the monoclonal antibody can be bound to a radioactive substance, a toxic drug or a chemical which stops cells growing and dividing. It delivers the substance to the cancer cells without harming other cells in the body.
downside to monoclonal antibodies
Monoclonal antibodies create more side effects than expected. They are not yet as widely used as everyone hoped when they were first developed.
signs of plant disease (7)
(Sally said danny got more dead plants)
Plant diseases can be detected by:
* stunted growth
* spots on leaves
* areas of decay (rot)
* growths
* malformed stems or leaves
* discolouration
* the presence of pests.
how can we identify plant diseases (3)
Identification can be made by:
* reference to a gardening manual or website
* taking infected plants to a laboratory to identify the pathogen
* using testing kits that contain monoclonal antibodies.
what can plant ion deficiency lead to
Plants can be damaged by a range of ion deficiency conditions:
* stunted growth caused by nitrate deficiency
* chlorosis caused by magnesium deficiency (leaves turn pale due to lack of chlorophyll)
what are nitrate ions needed for in plants
Nitrate ions needed for protein synthesis and therefore growth
what are magnesium ions needed for in plants
magnesium ions needed to make chlorophyll.
physical plant defences +info from pics
Physical defence responses to resist invasion of microorganisms.
* Cellulose cell walls.
* Tough waxy cuticle on leaves.
* Layers of dead cells around stems (bark on trees) which fall off. and are replaced with new ones
chemical plant defences +info from pics
Chemical plant defence responses.
* Antibacterial chemicals.
* Poisons to deter herbivores.
mechanical plant defences +info from pics
Chemical plant defence responses. * Antibacterial chemicals. * Poisons to deter herbivores.
