Topic 3 | Infection and Response Flashcards
What are pathogens and what types exist?
Pathogens are microorganisms that cause infectious diseases. They include viruses, bacteria, protists, and fungi.
What are the symptoms and spread of measles?
Measles symptoms include fever and a red skin rash. It spreads through droplet infection and is prevented by vaccination.
What are the symptoms and prevention of Salmonella?
Salmonella causes fever, stomach cramps, vomiting, and diarrhoea. It is prevented by vaccinating poultry, cooking food thoroughly, and maintaining hygiene.
What are the symptoms and spread of rose black spot?
Rose black spot causes purple or black spots on leaves, reducing photosynthesis. It spreads via water or wind and is prevented by fungicides and removing affected leaves.
How is malaria spread and prevented?
Malaria is spread by female Anopheles mosquitoes. Prevention includes using insecticide-treated nets, removing stagnant water, and taking antimalarial drugs.
What are the non-specific defences of the human body?
Skin: Acts as a physical barrier and produces antimicrobial secretions. Nose: Has hairs and mucus to trap pathogens. Trachea and bronchi: Secrete mucus and have cilia to waft mucus upwards. Stomach: Produces hydrochloric acid to kill pathogens.
How do white blood cells protect the body?
Phagocytosis: Engulf and consume pathogens. Antibodies: Bind to pathogens, clumping them for easier destruction. Antitoxins: Neutralise toxins released by pathogens.
How do vaccinations work?
Vaccinations introduce a dead or inactivated pathogen, stimulating white blood cells to produce antibodies. This provides immunity without causing the disease.
What are antibiotics and why can’t they treat viruses?
Antibiotics kill bacterial pathogens without damaging body cells. They cannot treat viruses because viruses use body cells to reproduce, making it difficult to target them without harming the host.
How does antibiotic resistance develop?
Antibiotic resistance develops when bacteria mutate and survive antibiotic exposure. These resistant bacteria then reproduce, increasing the population of resistant strains.
How was penicillin discovered?
Alexander Fleming discovered penicillin when he noticed that Penicillium mould killed bacteria on his culture plates, leading to the development of the first antibiotic.
How are monoclonal antibodies produced?
Monoclonal antibodies are produced by fusing lymphocytes (which produce antibodies) with tumour cells (which divide rapidly) to form hybridomas. These hybridomas produce identical antibodies.
What are the uses of monoclonal antibodies?
Pregnancy tests: Detect hCG hormone in urine. Laboratory testing: Measure hormone or chemical levels. Cancer treatment: Target cancer cells with specific antigens.
What are common signs of plant diseases?
Common signs include stunted growth, spots on leaves, areas of decay, abnormal growths, malformed stems or leaves, discolouration, and visible pests.
What are the physical defences of plants?
Waxy cuticle: Prevents pathogen entry. Cell walls: Provide a physical barrier. Bark: Layers of dead cells that fall off, taking pathogens with them.
What are the chemical defences of plants?
Plants produce poisons (e.g., foxgloves, tobacco) to deter herbivores and antibacterial compounds (e.g., mint, witch hazel) to kill bacteria.
What are the mechanical defences of plants?
Thorns and hairs: Deter animals. Leaf movement: Drooping or curling to dislodge insects. Mimicry: Tricking animals by appearing unhealthy or resembling other objects.
What are the effects of nitrate and magnesium deficiencies in plants?
Nitrate deficiency: Stunts growth as nitrates are needed for protein synthesis. Magnesium deficiency: Causes chlorosis (yellowing of leaves) as magnesium is needed for chlorophyll production.
What are the stages of clinical trials for new drugs?
Preclinical testing: Using cells, tissues, and animals. Clinical testing: Testing on healthy volunteers and patients to determine safety, efficacy, and dosage. Peer review: Results are reviewed by other scientists for accuracy.
What is herd immunity and how does it work?
Herd immunity occurs when a large proportion of the population is vaccinated, reducing the spread of a pathogen. This protects unvaccinated individuals by limiting the pathogen’s ability to spread.
