B5 Flashcards
What is a communicable disease?
Those spread from person to person or between animals and people. They can be caused by things like bacteria, viruses, parasites and fungi. They’re sometimes described as contagious or infectious diseases.
How do diseases interact?
People who have problems with their immune system have an increased chance of suffering from communicable disease.
Some types of cancer can be triggered by infection by certain viruses.
Immune system reactions in the body caused by infection by pathogen can sometimes trigger allergic reactions such as skin rashes are worse than the symptoms of asthma for asthma suffers.
Mental health issues such as depression can be triggered when someone is suffering from severe physical health problems, particularly if they have an impact on the persons ability to carry out every day activities or if they affect the persons life expectancy.
Factors that affect your health?
Poor diet
Stress
Life situation (access to medicines, healthy food, condoms)
What are the types of pathogen?
Bacteria (reproduce rapidly, make you feel ill by producing toxins that damage your cells and tissues)
Viruses (reproduce rapidly, live inside your cells and replicate themselves, the cell will then burst and release the new viruses, the cell damage is what makes you feel ill)
Protists (some are parasites that live on or inside other organisms and can cause them damage, transferred to the organism by a vector)
Fungi (grow and penetrate the human skin and the surface of plants causing disease)
How can pathogens be spread?
Water
Air
Direct Contact
3 viral diseases?
Measles:
It is spread by droplets from an infected person’s sneeze or cough.
Red skin rash, signs of a fever
Can be serious or even fatal if there are complications
Most people are vaccinated against it when they’re young
HIV:
Sexual contact, sharing bodily fluids
Flu-like symptoms
Attacks the immune cells
If the body’s immune system is badly damaged, it can’t cope with other infections or cancers.
Tobacco Mosaic Virus (TMV):
affects many species of plants
Mosaic pattern on the leaves of the plants, discolouring
Discolouration means the plant can’t carry out photosynthesis as well, so the virus affects growth
A fungal disease?
Rose black spot:
Purple or black spots develop on rose leaves
Leaves turn yellow and drop off
Less photosynthesis can happen, affects growth
Spreads by water or wind
Gardeners can treat the disease using fungicides and by stripping the plant of its affected leaves. These leaves then need to be destroyed so that the fungus can’t spread to other rose plants.
A protist disease?
Malaria:
Mosquitoes are vectors - they pick up the malaria protist when they feed on an infected animal.
Every time the mosquito feeds on another animal, it infects it by inserting the protest into the animals blood vessels.
Repeating episodes of fever. It can be fatal.
Stop the mosquitoes from breeding.
Protected using insecticides and mosquito nets.
Two bacterial diseases?
Salmonella:
Causes food poisoning
Fever, stomach cramps, vomiting and diarrhoea
Caused by toxins produced by bacteria
Food
Most poultry is given a vaccination against it in the UK
Gonorrhoea:
STD
Pain when urinating, thick yellow or green discharge from the vagina or penis.
Used to be treated with penicillin, but some of the bacteria has now become resistant to it.
Antibiotics and barrier methods of contraception.
How can we prevent the spread of disease?
Being hygienic (washing hands)
Destroying vectors (destroying insects using insecticides or by destroying their habitats)
Isolating infected individuals (prevents them from passing it on)
Vaccination (less likely to develop the infection and then pass it on)
Examples of our bodies defence systems?
Skin acts as a barrier (it also secretes antimicrobial substances which kill pathogens)
Hairs and mucus in your nose trap particles that could contain pathogens
The trachea and bronchi secrete mucus to trap pathogens
The trachea and bronchi are lined with cilia which waft the mucus up to the back of the throat where it can be swallowed
Hydrochloric acid in the stomach kills pathogens that make it that far from the mouth.
What are white blood cells three lines of attack?
White blood cells can engulf foreign cells and digest them. This is phagocytosis.
Every invading pathogen has unique molecules (called antigens) on its surface.
When some types of white blood cell come across a foreign antigen (i.e. one they don’t recognise) they will start to produce proteins called antibodies to lock onto the invading cells so that they can be found and destroyed by other white blood cells. The antibodies produced are specific to that type of antigen — they won’t lock on to any others.
Antibodies are then produced rapidly and carried around the body to find all similar bacteria or viruses.
If the person is infected with the same pathogen again, the white blood cells will rapidly produce the antibodies to kill it — the person is nafurally immune to that pathogen and won’t get ill.
Producing antitoxins - these counteract toxins produced by the invading bacteria.
What mineral ions do plants need?
Nitrates are needed to make proteins and therefore for growth. A lack of nitrates causes stunted growth.
Magnesium ions are needed for making chlorophyll, which is needed for photosynthesis. Plants without enough magnesium suffer from chlorosis and have yellow leaves.
Common signs of disease in plants?
Stunted growth
Abnormal growths (lumps)
Sports on the leaves
Malformed stems of leaves
Patches of decay (rot)
Discolouration
Physical defences that plants have?
Waxy cuticle, barrier to stop pathogens entering
Plant cells themselves are surrounded by cell walls made from cellulose, another barrier
Layers of dead cells around their stems (bark), another barrier
Chemical defences that plants have against pathogens?
Some can produce antibacterial chemicals.
Others produce poisons which can deter herbivores.
Mechanical defences of plants against diseases?
Thorns and hairs to stop animals from touching and eating them.
Leaves that droop or curl when someone touches them (knock insects of them, move away from things).
Mimic other organisms (looking like stones and pebbles so they aren’t eaten)
