INFECTION AND RESPONSE Flashcards
What are pathogens?
Microorganisms that enter the body and cause communicable disease
What do bacteria do?
They are very small cells which can reproduce rapidly inside the body
They produce toxins that damage cells and tissues
What do viruses do?
They reproduce rapidly in the body
They live inside cells and replicate themselves until the cell bursts and is damaged releasing the virus
What do protists do?
Eukaryotes and some are parasites
Parasites live in or on other organisms and cause damage (often transferred by vector)
What does fungi do?
They grow and penetrate human skin and the surface of plants causing diseases
What different ways can pathogens be spread?
Water
Air
Direct contact
What is measles?
A viral disease which is spread by droplets from an infected person’s sneeze or cough
What are the symptoms of measles?
Red skin rash
Fever
What is HIV?
A virus that spreads by sexual contact or by exchanging bodily fluids
It attacks the immune cells
What are the symptoms of HIV?
Flu-like symptoms
What is tobacco mosaic virus (TMV)?
It causes a mosaic pattern on the leaves of plants and some parts become discoloured so it cannot carry out photosynthesis so stunts growth
What is rose black spot?
It is a fungal disease that causes purple or black sports to form on the leaves of rose plants
Less photosynthesis so stunts growth
How is rose black spot disease spread?
Water or by the wind
What is malaria?
A disease caused by a protist
A mosquito is a vector and picks up the protist when they feed on an infected animal
When it feeds on another it infects it by inserting the protists into that animals blood vessels
What are the symptoms of malaria?
Repeating episodes of fever
What is samonella?
A bacteria that produces toxins that cause food poisoning
What are the symptoms of samonella?
Fever
Stomach cramps
Vomiting
Diarrhoea
What is gonorrhoea?
An STD caused by bacteria (used to be treated with penicillin)
What are the symptoms of gonorrhoea?
Pain when urinating
Thick yellow/green discharge from vagina or penis
What can be done to reduce or prevent the spread of disease?
Being hygienic
Destroying vectors
Isolating infected individuals
Vaccination
What does the body do to defend itself?
Skin - acts as a barrier to pathogens
Hairs and mucus in nose - traps pathogens
Trachea and bronchi - make mucus to trap pathogens and lined with cilia which waft mucus to the back of the throat where it can be swallowed
Stomach - produces hydrochloric acid which kills pathogens
How do white blood cells kill pathogens?
Phagocytosis - engulf foreign cells and digest them
What is the process of phagocytosis?
Pathogens have unique molecules on their surfaces called antigens
WBC’s produce proteins called antibodies which lock onto the invading cells antigens to destroy them
What is the process of phagocytosis?
Pathogens have unique molecules on their surfaces called antigens
WBC’s produce proteins called antibodies which lock onto the invading cells antigens to destroy them
How do vaccines work?
They inject small amounts of dead/inactive pathogens into the body which causes the production of antibodies so the body already has the correct antibodies if the real pathogen was to enter the body
What are the pros of vaccines?
Help control lots of communicable diseases
Epidemics can be prevented
What are the cons of vaccines?
Vaccines don’t always work
Sometimes you can have a bad reaction to them
What are painkillers?
Drugs that relieve pain but don’t tackle the cause of the disease or kill pathogens
What are antibiotics?
They kill the bacteria without killing your own body cells (not viruses)
Why don’t antibiotics kill viruses?
Viruses reproduce using your body cells so it is hard to create a drug that doesn’t kill the body cells
How can bacteria become resistant to antibiotics?
Bacteria can mutate and this can cause them to become resistant to an antibiotic (so only the non-resistant bacteria will be killed and the rest will reproduce etc)
What is aspirin and where is it from?
Painkiller to lower fever
Willow
What is digitalis and where is it from?
Treat heart conditions
Foxgloves
What are the three main stages in drug testing?
Preclinical (tested on human cells and tissues in a lab)
Tested on living animals
Human volunteers
What are the stages in human testing?
Tested on healthy volunteers to test safety
People with the disease to test efficiency and right dosage ( + placebo)
What are antibodies produced by?
Lymphocytes (type of WBC)
What are monoclonal antibodies?
Produced from lots of clones of a single WBC so they are all identical and can target one specific protein antigen
Lymphocytes don’t divide easily
Fuse tumour cell and B-lymphocyte to create a hybridoma
This clones to get identical cells which will produce the same antibodies (will be purified)
What are nitrates needed for in plants?
To make proteins so the plant can grow
What are magnesium ions needed for in plants?
For making chlorophyll which is needed for photosynthesis
What are some common signs that a plant has a disease?
Stunted growth
Spots on leaves
Patches of decay
Lumps
Malformed leaves/stems
Discolouration
How does the waxy cuticle on leaves defend the plant?
Provides a barrier to stop pathogens entering
How do cells in plants defend themselves?
Surrounded by a cell wall made of cellulose which forms a physical barrier
How do the stems of a plant defend itself?
Layer of dead cells which act as a barrier
How do plants defend themselves chemically?
Antibacterial chemicals kill bacteria
Some produce poisons
How do plants defend themselves mechanically?
Some have adapted to have thorns and hairs
Some leaves droop or curl when something touches them
Some can mimic other organisms
