4.1 Communicable Diseases Flashcards
Define pathogen
A microorganism that causes disease
What is a host
Organism in which a pathogen lives
Name the 4 types of pathogen
Virus
Bacteria
Fungi
Protist
Describe what bacteria are
Part of prokaryotae kingdom
Can rapidly divide (every 20 minutes)
Releases toxins to damage host cells
Name the examples of bacterial diseases in animals
Tuberculosis
Bacterial meningitis
Name the bacterial diseases in plants
Ring rot
How can bacterial diseases be treated
Antibiotics
Name examples of fungal diseases in animals
Athletes foot
Ringworm
Name the examples of fungal disease in plants
Black Sigatoka
How are fungal diseases treated
Anti fungal cream/spray
Name the examples of viral diseases in animals
HIV/aids
Influenza
Name the examples of protoctist diseases in animals
Malaria
Name the example of protoctista disease in plants
Blight
How are protists transmitted
By vectors
Define direct transmission
Passing a pathogen from a host to a new host with no intermediary
Define indirect transmission
Passing a pathogen from host to new host via a vector
Name the ways of direct transmission
Direct contact
Inoculation
Ingestion
Describe direct contact
Touching an infected person or something and picking up the disease
Describe inoculation
Break in the skin by animal bite, puncture wounds
Describe ingestion
Taking in contaminated food
Name the ways of indirect transmission
Famites
Droplet infection
Vectors
Describe famites
Inanimate objects which diseases get picked up by
Describe droplet infection
Droplets of saliva, mucus are expelled by your mouth
Describe vectors
Vectors transmit/ carry disease from hosts to hosts
Name the factors that increase transmission
Overcrowding
Poor diet
Poor ventilation
Poor waste disposal
Poor health
Climate change
Socioeconomic factors
Why are plants defences different to humans
Plants do not have an immune system but have structural, chemical, protein based defences
What are passive defences
Defences present before infection to prevent spread and entry of pathogen
What are the physical defences in plants
Cellulose cell wall
Lignin
Waxy cuticle
Bark
Stomata closing
Callus formation
What are the chemical defences in plants
Insect repellent
Insecticides
Antibacterial and antifungal
what are primary defences
prevent pathogens entering the body
name the primary non specific defences
skin
ciliated epithelial
wound repair
expulsion reflex
inflamation
describe how skin is a primary non specific defence
physical, chemical barrier
top layer is impermeable
secretes fatty acids to kill bacteria/lower pH
secretes lysosomes to catalyse breakdown of bacteria cell wall
describe how mucous membranes act as a primary non specific defence
epithelial cells covered by mucus
traps pathogens
cilia wafts mucus up and out of the lungs
goblet cells secrete mucus
describe how blood clotting acts as a primary non specific defence
exposure of platelets/ collagen in blood causes clotting response
Soluble fibrinogen converted into insoluble fibres
makes temporary seal to prevent infection
narrows blood vessels
describe how inflammation acts as a primary non specific defence
microorganisms in tissuess causes release of histamines and cytokines
= vasodilation of blood vessels = more permeable = wbc can enter tissue fluid
symptoms of inflammation
redness
swelling
pain
heat
describe how the expulsion reflex acts as a primary non specific defence
automatic reflex
expels pathogens by coughing, sneezing, vomiting
what is a secondary defence
used to fight pathogens that have entered the body
what are antigens
chemical markers/ membrane bound organelle used to recognise pathogens
what are antigens made out of
glycoproteins and glycolipids
what is an opsonin
protein molecules that attach to antigens on the surface of a pathogen
what is the role of opsonins
enhances ability of phagocytic cells to bind and engulf pathogens
can bind to a variety of pathogens
what is phagocytosis
type of endocytosis where particles/organisms are taken into the cell
what is a phagocyte
specialised cell in the blood and tissue fluid that engulf and digest pathogens
name the two types of phagocytes
neutrophil
macrophage
describe structure of a neutrophil and where are they found
multilobed nucleus
contain large no. of lysosomes
found in the blood vessels
explain how neutrophils work
binds to opsonin which is bound to antigens on pathogen
pathogen engulfed by endocytosis forming a phagosome
lysosomes fuse to phagosome (phagolysosome)
releases enzymes into it
digestion and harmless products released
describe what the role of a macrophage is
ingests and digests pathogens and presents pathogens antigens to other cells
explain the difference between the mode of action of a macrophage and neutrophil
n= fully digests it
m= doesnt fully digest it, presents the antigens and becomes antigen presenting cell
what is an antigen presenting cell
cell that isolates the antigen from pathogen and puts them on plasma membrane to be recognised by other cells
are macrophages or neutrophils bigger
macrophages
how do macrophages travel
travel as monocytes in the blood
Where are neutrophils and macrophages produced
Bone marrow
What does the specific immune response involve
Involves B lymphocyte cells and t lymphocyte cells
What is the main role of lymphocytes
To produce antibodies, long term protection of the disease, produces immunological memory through releasing memory cells
What cells are involved with cell mediated response
T cells
What does a T cell select
Antigen presenting cell or infected body cell
Name the steps in cell mediated responses
Clonal selection
Clonal expansion
Differentiation
What happens during Clonal selection in cell mediated response
Antigen presenting cell or infected body cell has specific antigens that are detected by T cells
What happens during clonal expansion in cell mediated response
Once T cell is selected it undergoes mitosis/ proliferation
What happens during differentiation in cell mediated response
Clones of T cells develop into 4 types
What type of cells do T cells differentiate into
T killer
T memory
T suppressor
T helper
What does a T killer cell do
Attacks and kills infected body cell/ APC that is displaying foreign antigens
What do T helper cells do
Releases cytokines that stimulates B cells to increase rate of mitosis and differentiation
What do T memory cells do
Provide long term immunity/ immunological memory and remain in the blood
What cells are involved in hummoral immunity
B cells
What do B cells select
Pathogens and antigen presenting cells
Explain clonal selection in the hummoral response
APC and pathogen are detected by B cells
Explain how clonal expansion is involved in hummoral response
Once b cell selected they must increase in numbers by mitosis/ proliferation
Explain what happens during differentiating in hummoral response
Once cloned they must be developed into 2 types
What are the two types that B cells differentiate into
Plasma cells
B memory cells
What do B memory cells do
Remain in the blood and act as immunological memory
What do plasma cells do
Manufactures and releases antibodies
What is an antibody
Protein molecule that is specific to antigens on foreign materials
What is antigen made of
4 polypeptide chains
Name the regions of antibodies
Variable region
Constant region
What is the variable region on an antibody
Where it binds to antigens and is specific to antigens
What is constant region of an antibody
Same in all antibodies
What are the two chain types in antibodies
Heavy chain and light chain
What does the hinge region in antibodies allow
Flexibility so it can move to bind to antigens
What bonds are in antibodies
Disulphide bridges
describe how the structure of an antigen allows it to perform its function
2 light and 2 heavy chains (4 polypeptide
chains)
variable region allows binding
antigen
two vr allow binding of more than
one (of the same) antigen
vr on different antibodies allows binding to different antigens
constant region allows
binding to phagocytes
hinge allows flexibility
disulfide bridges hold polypeptides
How do antibodies work
Act as opsonins
Agglutinins
Antitoxins
Explain how antibodies act as opsonins
Binds the phagocyte and pathogen together
Explain how antibodies work as agglutinins
Causes pathogens to clump/ stick together
Makes it easier for pathogens to be engulfed
Explain how antibodies work as antitoxins
Antibodies bind to the toxins and neutralise it and prevents them getting into body cells
What is an autoimmune disease
Own immune system begins to detect own cells as foreign
Name examples of autoimmune diseases
Lupus
Arthritis
How can autoimmune diseases be treated
Anti inflammation
Steroids
Immunosuppressant
What is a vaccination
Provides immunity to specific diseases that stimulate an immune response
What are the forms of vaccines
Dead
Attenuated
Toxoids
Antigens
Genetically Engineered antigens
How does a vaccine work
Injected into blood
Primary response triggered as antibodies and memory cells produced
Person is then infected
Secondary immune response triggered
Antibodies produced quicker so pathogen is destroyed
Name the types of immunity
Natural
Artificial
Passive
Active
What is natural immunity
Gained in the normal course of living processes
What is artificial immunity
Deliberately exposing antigens and antibodies
What is passive immunity
Getting given the antibodies
What is active immunity
Antibodies are made by the body as part of the immune response
name an example of natural passive and natural active immunity
np= breastfeedin
na= getting ill and recovering
name an example of artificial passive and artificial active
ap= emergancy treatment for tetanus, rabies
aa= vaccination
why do we vaccinate people
many diseases can be fatal whilst waiting for primary response
provides long term immunity
helps prevents epidemics/pandemics
define antibiotic
Chemical that prevents the growth of microorganisms (bacteria)
Personalised medicine
development of medicines for individuals
Developing specific drugs for individuals with particular conditions by sequencing genes
synthetic biology
reengineering of biology, production of new molecules that mimic natural processes to produce new biological systems
Sources of new medicines
accidental discovery eg. Penicillin
Traditional remedies
Wildlife observation
Plant research
Personalised medicine
Synthetic biology
benefit and risk of antibiotics
Prevent infection of wounds
Over use and misuse has caused antibiotic resistance to occur
