B3 Flashcards
What is a pathogen?
Pathogens are microorganisms that cause infectious disease.
What are the 4 different types of pathogen?
- Bacteria. 2. Virus. 3. Protists. 4. Fungi
How can bacteria harm you?
They reproduce rapidly and produce toxins which damage your cells and tissues.
How can a virus harm you?
They reproduce rapidly inside your cells and the cell can burst, releasing the virus. The cell damage is what makes you feel ill.
How can some protists harm you?
They live on or in other organisms and can cause damage. They are spread by a vector.
How come some fungi harm you?
Some have a body made from hyphae which can grow and penetrate human skin causing diseases. They have huge spored which can be spread to other plants or animals.
How can pathogens be spread? (3)
- Water - e.g. drinking or bathing in dirty water. 2. Air - droplets carried in the air when you sneeze or cough. 3. Direct contact - e.g. by touching contaminated surfaces.
What are 3 viral diseases?
- Measles. 2. HIV. 3. Tobacco Mosaic Virus
Measles. How is it spread?
- Droplets from an infected person’s sneeze or cough.
Measles. Symptoms?
- Red skin rash and fever.
Measles. What happens and is it dangerous?
- Yes - complications can be fatal (could lead to pneumonia).
Measles. How is it prevented?
- Vaccination.
HIV. How is it spread?
- Exchanging bodily fluids e.g. during sex or sharing needles.
HIV. Symptoms?
- Flulike symptoms.
HIV. What happens and is it dangerous?
- Virus attacks immune cells and if enough is damaged it can’t cope with other infections e.g. cancer (this is now AIDS).
HIV. How is it treated?
- Antiretroviral drugs (at first).
HIV. How is it prevented?
Abstinence
TMV. How is it spread?
- Hands of farmer and infected tools.
TMV. Symptoms?
- Discoloured pattern on leaves.
TMV. What happens and is it dangerous?
- Lack of photosynthesis affects growth.
TMV. How is it prevented?
- Wash hands and tools and destroy infected plants.
What are 2 bacterial diseases?
- Salmonella. 2. Gonorrhea.
Salmonella. How is it spread?
- Uncooked poultry.
Salmonella. Symptoms?
- Fever, abdominal cramps, vomiting and diarrhea.
Salmonella. How is it prevented?
- Poultry are vaccinated and cook poultry thoroughly.
Gonorrhea. How is it spread?
- Sexual contact.
Gonorrhea. Symptoms?
- A yellow or green discharge from the vagina or penis and pain on urinating.
Gonorrhea. What happens and is it dangerous?
It is caused by a bacterium and was easily treated with the antibiotic penicillin until many resistant strains appeared.
Gonorrhea. How is it prevented?
The spread can be controlled by treatment with antibiotics or the use of a barrier method of contraception
What is the fungal disease?
Rose black spot.
Rose black spot. How is it spread?
Water or wind.
Rose black spot. Symptoms?
Purple or black spots develop on leaves.
Rose black spot. What happens and is it dangerous?
Lack of photosynthesis - lack of growth.
Rose black spot. How is it treated?
Fungicides and/or removing and destroying the affected leaves
What is a protist disease?
Malaria
Malaria. How is it spread?
Mosquitos (vectors)
Malaria. How is it prevented?
Preventing the mosquitos from breeding and by using mosquito nets to avoid being bitten.
Malaria. Symptoms?
Fever
How is the skin a defense system?
It acts as a barrier to pathogens. It releases antimicrobial substances which kill pathogens.
How is the nose a defense system?
Hair and mucus trap pathogens.
How is the trachea and bronchi a defense system?
Secretes mucus to trap pathogens. Lined with cilia to move mucus and pathogens.
How is the stomach a defense system?
Produces HCl which kills pathogens.
What does the immune system do if a pathogen enters?
It kills it.
Phagocytosis and continued (3)
- White blood cells engulf foreign cell and digests it. 2. Specific antibodies produced which kill pathogen. 3. Antitoxins produced.
How does a vaccination work? (3)
- Introduce small quantities of dead or inactive forms of a pathogen into the body. 2. Stimulates the white blood cells to produce antibodies. 3. If the same pathogen re-enters the body the white blood cells respond quickly to produce the correct antibodies - preventing infection.
How do vaccines work in society?
Less people carry and spread the pathogen so should be eliminated.
Pros of vaccines (2)
- Helped control communicable diseases e.g. smallpox and polio. 2. Big epidemics and pandemics shoudn’t spread as fast.
Cons of vaccines (2)
- They don’t always work. 2. Bad reaction like swellings - but these are very rare.
How do antibiotics work?
Antibiotics - such as penicillin - are medicines that help to cure bacterial disease by killing infective bacteria inside the body. It is important that specific bacteria should be treated by specific antibiotics.
What is a new great concern with antibiotics?
Antibiotic resistance.
What can antibiotics kill?
Bacteria only
What do painkillers do?
Painkillers and other medicines are used to treat the symptoms of disease (treat the pain) but do not kill pathogens.
What does the heart drug digitalis originate from?
Foxgloves
What does the painkiller aspirin originate from?
Willow
Who and how was penicillin discovered?
Penicillin was discovered by Alexander Fleming from the Penicillium mould.
What are new drugs tested for?
Toxicity - is it safe? side effects? Efficacy - does it work? Dosage - how much is safe?
Where is preclinical testing done?
Preclinical testing is done in a laboratory using cells, tissues and live animals.
What happens in clinical testing?
They use volunteers and patients. 1. Very low doses of the drug are given at the start of the clinical trial. 2. If the drug is safe, further clinical trials are carried out to find the optimum dose for the drug.
What is a double blind trial?
Both the doctors and patients don’t know who has the placebo or the actual drug.
What are monoclonal antibodies produced from and what do they do?
They 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 in a lab?
They are produced by stimulating mouse lymphocytes to make a particular antibody. The lymphocytes are combined with a tumour cell to make a cell called a hybridoma cell. The hybridoma cell can both divide quickly and make the antibody. 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.
What are some uses of monoclonal antibodies? (4)
- For diagnosis such as in pregnancy tests 2. In labs to measure the levels of hormones and other chemicals in blood or to detect pathogens. 3. In research to locate or identify specific molecules in a cell or tissue. 4. To treat some diseases e.g. for cancer.
Why are monoclonal antibodies not used hugely?
Lots of side effects.
How can plant diseases be detected? (5)
- Stunted growth. 2. Spots on leaves 3. Areas of decay (rot). 4. Discolouration. 5. The presence of pests.
How can plant diseases be identified? (3)
- Reference to a gardening manual or website. 2. Taking infected plants to a laboratory to identify the pathogen. 3. Using testing kits that contain monoclonal antibodies.
What is an aphid? (3)
Aphids block the phloem, preventing sugar transport and causing stunted growth. Aphids directly weaken the plant by consuming essential nutrients. Aphids introduce fungal infections.
What is caused from a nitrate deficiency?
Stunted growth.
What is caused from a magnesium deficiency?
Chlorosis (yellow discolouration of the plant).
What are nitrate ions needed for?
Protein synthesis and therefore growth.
What are magnesium nitrate ions needed for?
Making chloropyll.
What are some physical defense responses to resist invasion of microorganisms (in plants)? (3)
- Cellulose cell walls. 2. Tough waxy cuticle on leaves. 3. Layers of dead cells around stems (bark on trees) which fall off.
What are some chemical plant defense responses (in plants)? (2)
- Antibacterial chemicals. 2. Poisons to deter herbivores.
What are some mechanical adaptations (in plants)?
- Thorns and hairs deter animals. 2. Leaves which droop or curl when touched. 2. Mimicry to trick animals
