B2 Flashcards
what is disease?
a condition that commonly damages cells of the host and impairs the functioning of the organism
what are the causes of disease?
infection, mutation, environmental conditions, trauma, lifestyle
what is a communicable disease?
a disease that can spread between organisms
what causes disease?
pathogens infecting the bacteria
what is a pathogen?
type of microorganism that causes disease
- bacteria, viruses, protists and fungi
what is a non communicable disease?
disease that cannot be passed onto another organism
examples of non communicable disease
cardiovascular and respiratory diseases, cancers and diabetes
what are symtoms?
changes in the organism that indicate disease is presnt
what is the incubation period
time between being infected with a pathogen and showing symptoms of the disease
what are bacteria?
- very small cells that can reproduce rapidly
- they produce toxins that damage cells and tissues
what are viruses?
- not cells
- replicate themselves inside the infected organism’s cells which then burst and releases the viruses
what are protists?
- eukaryotic, single celled and vary in size
what are fungi?
- have hyphae, thread like structures
- hyphae can grow and penetrate human skin and the surface of plants
- can produce spores that can be spread
how are communicable diseases spread?
water, air, on surfaces, body fluids, animal vectors, soil, food
water transmission
- drinking or bathing in dirty water
- cholera gets spread by contaminated water by the diarrhoea of other sufferers
air transmission
- pathogens can travel by the wind and in the air
- airborne pathogens can be breathed in by others
- flu, chalara ash dieback
surface transmission
- touching contaminated surfaces
- in plants, TMV when infected leaves rub against healthy leaves
- in humans, touching the same things as an infected person
- tobacco mosaic disease, athletes foot
body fluids transmission
- blood, breastmilk, semen
- exchange of body fluids
- HIV is a virus spread by exchanging body fluids , which gives flu like symptoms. the virus enters the lymph nodes and attacks the immune system so it cants cope with other infections or cancers. by this part, its known as AIDS or late stage HIIV
animal vectors transmission
- animals that spread disease are called vectors
- malaria from mosquitoes that pick up protists and when it feeds on an animal, it inserts the protists into their blood, causing fever
soil transmission
- comes from pathogens that live in the soil
- bacteria that causes crown gall disease live in soil and once it enters a plant is can grow galls which damages the plant tissue
food transmission
- can come from eating contaminated food
- salmonella is found in some foods like raw meat
- if kept for too long or not cooked property, it can cause food poisoning
defence systems
- non specific
- always presnt
- physical, microbial or chemical
physical defences
mucus and cilia in respiratory tracts
- mucus traps pathogens and cilia wafts pathogens to back of the throat
skin
- acts as a barrier
platelets
- helps blood clot helping to plug the wound
chemical defences
eyes
saliva
stomach
eyes as defence
tears produce lysozyme which break down bacteria on surface of eye
saliva as defence
contains molecules that kill pathogens that enter the mouth
stomach as defence
produces hydrochloric acid which kills pathigens
microbial defences
pathogens that make it past the saliva and stomach and enter intestine where they compete with the bacteria that live there to survive
phagocytosis
phagocytes have a flexible membrane, allowing them to engulf foreign cells and digest them
antibodies
Antibodies work by recognizing and binding to specific pathogens, such as viruses and bacteria. This binding process neutralizes the pathogen and marks it for destruction by other components of the immune system. The immune system also remembers the pathogen, so if it infects the body again in the future, the immune system can respond more quickly and effectively.
antitoxins
Antitoxins are substances produced by the immune system to neutralize toxins produced by harmful bacteria. They work by binding to the toxins and inactivating them, preventing them from causing harm to the body.
how reduce and prevent spreading diseases in animals
- being hygienic
- sterilising wounds
- living in sanitary conditions
- destroying infected animals
- isolating infected animals
- vaccination
- contraception
how to reduce and prevent spreading diseases in plants
- regulating plant movement
- destroying infected plants
- crop rotation
- polyculture
- chemical control
- biological control
how to regulate plant movemnet?
make sure infected plants dont come into contact with infected ones
polyculture
growing different types of plants in a single area
chemical control
fungicides can be used to kill fungal infections but can lead to the evolution of resistant strains
biological control
one organism is used to control a pest or pathogen
the immune system
- destroys pathogens that make it past defence systems
- they consume pathogens then produce antibodies and antitoxins
- contains white blood cells
what is vaccination?
dead, inactive or weakened pathogens are injected into the body
what is phagocytosis?
- Phagocytosis is carried out by a special type of white blood cell called a phagocyte.
- The first step is for the phagocyte to track down a pathogen, and then bind to it.
- The phagocyte’s membrane will then surround the pathogen and engulf it.
- Finally, enzymes inside the phagocyte break down the pathogen in order to destroy it.
whjat does an antitoxin do?
Bind and neutralise the toxins produced by bacteria