communicable diseases Flashcards
what are the four types of organisms that can cause diseases
- bacteria
- fungi
- Protoctista
- viruses
what is communicable disease
is spread from person to person (infectious)
what are pathogens
microorganism that cause disease
how can we reduce the spread of pathogens
vaccinations
what are the four things, that pathogens do during there lifecycle
- travel from host to host
- enter host tissue
- reproduce
- leave host tissue
what is direct transmission
is where a pathogen is passed on from one individual to another without any intermediate
what is indirect transmission
is where pathogens travel from one individual to another via an intermediate (water, food, air, or another organism (vector)
what can effect rate of transmission ( 7 possible reasons)
- Climate change
- poor ventilation
- international travel
- poor health and diet,
- economic development, and land use e.g., waste disposal
- human demographics and behaviour (overcrowding and homeless)
- microbial adaption and change.
why are plants useful host to pathogens
due to the supply of carbohydrates, proteins and oils
what is the role of the xylem tissue
to transport water and mineral ions, from the roots to other parts of the plant
what is the role of the cambium tissue
the layer of actively dividing cells between xylem (wood) and phloem (bast) tissues that is responsible for the secondary growth of stems and roots.
what is the role of the plasmodesmata
is a narrow thread of cytoplasm, that passes through the cell wall of adjacent plant cells, and allows them to communicate between each other
what are sieve plates and sieve tubes
found in phloem, and allow sucrose and amino acids to travel through (acts like a sieve)
what is cellulose
a polysaccharide
what are the toxic chemicals in the xylem called
tyloses
what are the brown spots on a plant know as
mycosis
what is a primary defence
prevents pathogens, from entering the body (non-specific)
what process is skin made by
mitosis
what makes mucus
goblet cells
what is the role of cilia
to waft mucus, up the airways (bronchioles, bronchi, trachea) to be expelled (sneezed or coughed) or digested into the stomach
what are antigens
cell surface membranes, that are specific to the organism
what are the two main types of phagocytes
neutrophil and macrophages
what comes before macropahges
monocytes
how are phagocytes, specialised for their function
- can change shape
- large amounts of ribosomes, to make proteins, in order to make enzymes, to break down the cells when ingested.
what is humoral
when cells are attacking invaders, outside of the cell
what is cell mediated
where they are attacking invader inside of the cell
T cells
made in the bone marrow are cell mediated and attack outside of the cell
B cells
made in the bone marrow, are humoral and made outside of the cell
what do T helper cells do
release cytokines which simulates b cells to develop and stimulate phagocytosis in phagocytes.
what do T killer cells do
attacks and kills body cells which are injected
what do T memory cells do
provide long term immunity after injection
what do T regulator cells do
shut down the immune response, once the pathogen has been removed
what do plasma cells do
produce antibodies
what are Monokines
released by macrophages, these attract neutrophils and can stimulate B cells to divide.
what are Monokines
released by macrophages, these attract neutrophils and can stimulate B cells to divide.
what are Interleukins
produce T cells and macrophages, stimulate proliferation (clonal expansion of B and T cells)
what are interferon
many cells produce this, it can inhibit virus replication and stimulates T killer cells (cell mediated)
why are exchange surfaces more susceptible to pathogens
due to having thin exchange surfaces in the airways, in order to allow for diffusion of oxygen into and out of the blood
why is coughing, sneezing and vomiting useful
- due to microorganisms and there toxins leading to irritation
- it is a reflex action to expel air or food
what are histamines
histamines are released by mast cells and and cause vasodilation to occur, this means that more blood goes to the infected area, and they also make the capillary walls more permeable to white blood cells and proteins.
what are antigens
cell surface membrane proteins or glycoproteins, that are intrinsic to the plasma membrane ( they are specific to the organism)
what are opsonin’s
they are proteins, that attach to antigens on surface the surface of pathogens to enable phagocytosis. ( they are a type of antibody, but opsonin’s are not very specific)
what are the two main types of phagocyte
Neutrophil and macrophages
what is the purpose of an antigen presenting cell (APC)
to display the pathogen antigens on there surface, in addition they initiate a specific immune response
how are phagocytes specialised for their function
- can change shape
- large amounts of ribosomes to make protein, to make enzymes to break down cells
what is clonal selection
The process of matching the antigens on an antigen presenting cells with the antigen receptors on B and T lymphocytes.
what is clonal expansion
The production of many genetically identical daughter cells through cell division of the activated B or T lymphocyte after clonal selection.
what is autoimmune disease
- when the immune system attacks a part of the body
- when antibodies attack our own antigens (sometimes, due to some antigens not normally being exposed)
- genetic and environmental factors involved
be able to understand the summary table on page 37
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what is an opsonin
a coat on the surface of the pathogen to increase the chance of phagocytosis
what is agglutinin
helps to clump pathogens together
what is an anti - toxin
binds to molecules produced by pathogens, which are toxic, ( they neutralise the toxin)
what is lysis
lysis, cause the bacteria’s cell membrane to rupture
what is meant by the immunological memory
the ability to fight the infection, more quickly due to memory cells
what are the four different types of immunity
- natural active (NA)
- artificial active (AA)
- natural passive (NP)
- artificial passive (AP)
what is herd vaccination
when the vaccination of a significant portion of population ( or herd) provides a measure of protection for individuals who have not developed immunity
what is ring vaccination
a strategy that is used to inhibit the spread of a disease by vaccinating only those who are most likely to be infected
what is a attenuated organism
A WEAKENED organism that won’t cause disease
what are the 7 types of ways we can discover new medicines
- accidental discovery
- traditional
- observing wildlife
- plant research
- research into disease causing mechanisms
- personalised medicine
- synthetic biology
what is accidental discovery
when a useful compound is found without the initial aim of doing so.
what is traditional discovery
where people use traditional medicines and remedies that are thousands of years old, using plants and animals.
what is observing wildlife
observations of animals in there natural habitat to see what plant they appear to use for medicinal purposes
what is plant research
scientist use traditional remedies and observations of animal behaviour, as a starting point for further more detailed plant research
what is research into disease causing mechanism
rather than just searching for new chemical compounds, some pharmaceutical companies are conducting research on how the target pathogen actually causes disease
what is synthetic biology
this process, involves the use of technology to design and make biological molecules including artificial proteins, cells and even microorganisms
what are antibiotics
antibiotics are medicines that fight infections caused by bacteria in humans and animals by either killing the bacteria or making it difficult for the bacteria to grow and multiply.
outline how bacteria are becoming resistant
There are two main ways that bacterial cells can acquire antibiotic resistance. One is through mutations that occur in the DNA of the cell during replication. The other way that bacteria acquire resistance is through horizontal gene transfer.
how long do neutrophils last
around 5 days
how long do macrophages last
around 2-3 months
what does a lobed nuclues help a neturophil to do.
to change shape, thus enabling them to squeeze through gaps in the bodies tissue.
what does a lobed nucleus help a neutrophil to do
to change shape thus being able to squeeze through gaps in the bodies tissue
what is the role of cytokines
attract (named) phagocytes
what is the role of opsonin’s
bind to pathogens / foreign cells / antigens and increase phagocytosis / recognition by phagocytes;
why can bacteria be killed by antibiotics
due to the antibiotics, inhibiting specific bacterial metabolic pathways.
how do fungi reproduce
by sending out reproductive hyphae
name the 3 bacteria
- tuberculosis
- bacterial meningitis
- ring rot
name the 3 viruses
- HIV/AIDS
- influenza
- tobacco mosaic virus
name the 2 Protoctista
- malaria
- potato/tomato late blight
name the 3 fungi
- black sigatoka
- ringworm
- athletes foot
what are terpenoids
a range of essential oils, that have antibacterial and antifungal properties. They also produce a scent.
what are phenols
- these have antibiotic and antifungal properties.
- tannins, found in bark inhibit insect attack by binding to salivary proteins and digestive enzymes.
what are alkaloids
nitrogen containing compounds, with a bitter taste to inhibit herbivore feeding They also inhibit enzyme activity and key metabolic process such as protein synthesis.
what are defensive proteins
- small cysteine - rich proteins, with board anti-microbial activity.
- act on molecules in the plasma membrane of pathogens, inhibiting ion transport channels.
what are hydrolytic enzymes
found in spaces between cells and can digest key structural components of pathogens
what is the general structure of an antibody
