B10 - Diseases and Immunity Flashcards
What is a disease? [2]
the state of the body when it cannot cope with changes by the normal homeostatic methods
What is a pathogen? [1]
a disease causing organism
What is a transmissible disease? [2]
a disease in which the pathogen can be passed from one host to another
What are examples of non-transmissible diseases? [3]
- red-green colour blindness = genetics
- heart disease = diet
- cystic fibrosis = genetics
Name the features of a bacteria cell. [8]
- cell wall
- cell membrane
- ribosomes
- cytoplasm
- nucleoid
- plasmid
- pili
- capsule
What is a nucleoid? [2]
- DNA
- circular chromosome
What is pili? [1]
helps stick to the cells
What is the cell wall in a bacteria cell made of? [1]
peptodoglycan
What do viruses include? [3]
- protein coat
- DNA/RNA
- envelope
What are 4 facts about viruses? [4]
- they are particles rather than cells
- they don’t have a cellular structure
- they only reproduce inside other living cells
- they are both pathogens and parasites
How do transmissible diseases spread? [2]
- through direct contact
- through indirect contact
How is a pathogen transmitted by direct contact? [1]
through blood and other body fluids
How is a pathogen transmitted indirectly? [4]
- from contaminated surfaces
- food
- animals
- air
How does a clean water supply prevent transmission of pathogens? What’s the process? [3]
- filter the water
- add chlorine
- kills pathogens
How does hygienic food preparation prevent transmission of pathogens? What’s the process? [3]
- preparing food in hygienic conditions
- reduces the spread of pathogens from work surfaces and chopping boards to food
- kills pathogens
How does good personal hygiene prevent transmission of pathogens? What’s the process? [2]
- washing your hands after going to the toilet
- prevents the spread of disease
How does waste disposal prevent transmission of pathogens? What’s the process? [3]
- not letting rubbish build up
- having systems in place to safely dispose of things like soiled bandages and used needles
- prevents the spread of disease
How does sewage treatment prevent transmission of pathogens? What’s the process? [3]
- having a good system for sewage treatment
- prevents sewage from contaminating drinking water
- reduces the spread of water-borne pathogens
What are the different body defences against pathogens? [4]
- skin
- hairs in the nose
- stomach acid
- mucus
What type of barrier is the skin and how does it work? [2]
- mechanical barrier
- if damaged, blood clots are formed by platelets to quickly seal cuts and prevent the entry of pathogens
What type of barrier are the hairs in the nose and how do they work? [2]
- mechanical barrier
- traps particles from the air that could contain pathogens
What type of barrier is stomach acid and how does it work? [3]
- chemical barrier
- stomach produces acid which kills pathogens
- gets rid of stuff in food and water
What type of barrier is mucus and how does it work? [3]
- chemical barrier
- cells lining the trachea secrete mucus which traps pathogens in incoming air
- ciliated cells waft the mucus back up to the throat to be swallowed
What are the features of viruses? [2]
- protein coat
- genetic material
What is the immune system’s main form of defence? [1]
white blood cells
What are the 2 types of white blood cells and their functions? [4]
- lymphocytes: make antibodies
- phagocytes: engulf and digest the pathogen
What is different in every pathogen? [1]
antigen
What does a different antigen in each pathogen mean? [1]
it means that a different antibody is needed for each type of pathogen
How are antibodies and antigens related? [1]
they are complimentary in shape
What is the process called of engulfing and digesting? [1]
phagocytosis
What are the adaptations for phagocytes? [3]
- contains digestive enzymes in their cytoplasm
- irregular shape so they can squeeze through gaps in capillary walls
- sensitive cell membrane to detect micro organism
What are the adaptations for lymphocytes? [2]
- pathogens have special protein markers
- large nucleus contains many copies of genes for antibody production
Outline the process of vaccination. [4]
- vaccine contains small amounts of dead or a weakened form of the pathogen
- inserted into the body usually by injection
- vaccination stimulates an immune response causing lymphocytes to produce antibodies to that pathogen
- memory cells are produced
What does the vaccination cause the body to produce? [2]
- antibodies
- memory cells
What are memory cells? [1]
they have long-lasting immunity
How do memory cells work? [3]
- they keep the instructions for making those antibodies again if the pathogen enters the body
- this means that the next time round the antibodies can be made very quickly and in large quantities
- this means the pathogen is destroyed before it can multiply
What are antibodies? [2]
- proteins that bind to antigens leading to direct destruction of pathogens
- marking of pathogens for destruction by phagocytes
What is active immunity? [2]
defence against a pathogen by antibody production in the body
When is active immunity gained? [1]
after an infection by a pathogen of vaccination
What is needed for pathogens to reproduce? [3]
- suitable temperature
- food
- moist
