topic 3 - infection and response Flashcards
What are pathogens?
Pathogens are microorganisms that cause infectious disease, including viruses, bacteria, protists, and fungi. They can infect plants or animals and spread through direct contact, water, or air.
Describe the characteristics of viruses.
Viruses are very small and move into cells, using the host’s biochemistry to make copies of themselves, which leads to the cell bursting and releasing copies into the bloodstream, causing the individual to feel ill.
How do bacteria reproduce and what do they produce?
Bacteria multiply quickly through a process called binary fission and produce toxins that can damage cells.
What is a protist?
Some protists are parasitic, meaning they live on or inside humans and animals, causing damage.
How do fungi reproduce and spread?
Fungi can be single-celled or multicellular with hyphae. They produce spores that spread to other organisms.
List the ways pathogens are spread.
- Direct contact: Examples include kissing and touching contaminated surfaces. 2. By water: Contact with dirty water. 3. By air: Pathogens can be carried in droplets expelled when sneezing, coughing, or talking.
What human behaviors can reduce the spread of disease?
Improving hygiene, reducing contact with infected individuals, and removing vectors are ways to limit the spread of pathogens.
How does vaccination work?
Vaccination involves injecting a small amount of a harmless pathogen to stimulate an immune response, making individuals immune so they cannot be infected or pass the disease on.
What are the symptoms of measles, and how is it spread?
Measles symptoms include fever and red skin rash, and it is spread through droplet infection.
What is HIV and how is it transmitted?
HIV is a virus that attacks the immune system and leads to AIDS. It is transmitted through sexual contact or exchange of bodily fluids.
What methods can reduce the spread of HIV?
Methods include using condoms, not sharing needles, screening blood transfusions, and bottle-feeding infants of HIV-positive mothers.
What are the symptoms and transmission method of Salmonella food poisoning?
Symptoms of Salmonella include fever, stomach cramps, vomiting, and diarrhoea. It is transmitted through ingesting bacteria from raw meat and eggs.
How can bacterial diseases like Gonorrhoea be prevented?
Gonorrhoea can be prevented by using condoms and antibiotics for treatment.
What results do fungal diseases like Rose black spot cause in plants?
Rose black spot causes purple or black spots on leaves, reducing photosynthesis and causing leaves to turn yellow and drop early.
Identify the vector for malaria and its prevention.
The vector for malaria is the female Anopheles mosquito. Prevention methods include using insecticide-treated nets and removing stagnant water.
How does the non-specific defence system protect the body?
The non-specific defence system includes the skin, nose, trachea and bronchi, and stomach, which prevent pathogens from entering the body.
What is phagocytosis?
Phagocytosis is the process where immune cells engulf and consume pathogens, destroying them and preventing illness.
How do vaccines stimulate immunity?
Vaccines replicate the first infection to stimulate white blood cells to produce antibodies before the individual has been infected, resulting in immunity.
What are antibiotics, and how do they differ from painkillers?
Antibiotics kill bacterial pathogens without harming body cells, while painkillers, like aspirin, only treat symptoms, not the cause of disease.
What is the concern regarding antibiotic resistance?
Bacteria are becoming resistant to antibiotics due to mutations and reproduction of resistant strains, leading to ineffective treatments.
Describe the process of developing new drugs.
New drugs are discovered in plants and microorganisms, synthesized by chemists, and tested for safety and efficacy through preclinical and clinical trials.
How are monoclonal antibodies produced?
Monoclonal antibodies are produced by combining lymphocytes that make antibodies with tumor cells that divide rapidly, creating hybridomas that produce identical antibodies
What are some applications of monoclonal antibodies?
They are used in pregnancy tests, laboratories to measure hormones, research, and treatment of diseases by targeting specific antigens
Explain how monoclonal antibodies are used in pregnancy tests.
Pregnancy tests use mobile antibodies that bind to hCG hormone in urine, forming complexes that are captured by stationary antibodies, indicating pregnancy with a blue line.
What is the purpose of using placebo in clinical trials?
Placebos are used to compare the effects of a new drug against a non-active substance, removing bias and determining the drug’s effectiveness.
What are the advantages of using monoclonal antibodies?
- They only bind to specific cells, meaning healthy cells are not affected.
- They can be engineered to treat many different conditions.
What are the disadvantages of using monoclonal antibodies?
- It is difficult to attach monoclonal antibodies to drugs.
- They are expensive to develop.
- As they were produced from mice lymphocytes, they often triggered an immune response when used in humans.
What are the common signs of plant diseases?
- Stunted growth indicating nitrate deficiency.
- Spots on leaves indicating black spot fungus on roses.
- Areas of decay indicating black spot fungus on roses, blights on potatoes.
- Abnormal growths (crown galls caused by bacterial infection).
- Malformed stems or leaves due to aphid infestation.
- Discolouration indicating magnesium deficiency, or tobacco mosaic virus.
- Pests on leaves such as caterpillars.
How can you identify the disease that a plant has?
- Using a gardening manual or website.
- Identifying the pathogen by observing the infected plant in a laboratory.
- Using monoclonal antibodies in testing to identify the pathogen.
What are the plant diseases that need to be learnt?
- Tobacco mosaic virus (viral disease).
- Black spot (fungal disease).
- Aphids (insects).
What is the effect of nitrate deficiency on plants?
Nitrate deficiency can stunt growth because nitrates in the soil convert sugars made in photosynthesis into proteins, which are needed for growth.
What is the effect of magnesium deficiency on plants?
Magnesium deficiency can cause chlorosis because magnesium is needed to make chlorophyll, the green pigment vital in photosynthesis. If less is being made, parts of the leaves appear green and yellow.
What are the physical defences of plants against pathogens?
- Tough waxy cuticle stops entry into leaves. 2. Cellulose cell walls form a physical barrier. 3. Layers of dead cells around stems (such as bark) stop pathogens from entering.
What are the chemical defences plants have?
- Poisons (e.g., from foxgloves, tobacco plants, deadly nightshades, yew) deter herbivores.
- Antibacterial compounds (such as those from mint plant and witch hazel) kill bacteria.
What are the mechanical defences of plants?
- Thorns and hairs make it difficult and painful for animals to eat them.
- Some leaves can droop or curl when touched to move insects off.
- Mimicry to trick animals (e.g., some plants droop to look unhealthy or have patterns resembling butterfly eggs).
What adaptations do some plants have to avoid predation?
Species from the ice plant family have a stone and pebble-like appearance to avoid predation.
