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ocr a biology 🧬 > 4.1.1 communicable diseases and the immune system > Flashcards

4.1.1 communicable diseases and the immune system Flashcards

1
Q

what is a pathogen

A

an organism that causes disease by taking nutrition from another organism or causing it harm

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2
Q

what does parasitic mean

A

organisms that live in or on a host and take their nutrition

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3
Q

what is fungi

A

eukaryotic
non-pathogenic
parasitic
release spores and multiply via budding
grow under skin

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4
Q

what is a virus

A

akaryotic (non-living)
uses cell’s nucleus to multiply

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5
Q

what is a protoctista

A

eukaryotic
non-pathogenic
parasitic
require a host
release toxic waste

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6
Q

what is bacteria

A

prokaryotic
non-pathogenic
multiply by binary fission
release toxic waste

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7
Q

what is tuberculosis

A

bacteria
kills cells and tissues and affects respiratory system

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8
Q

what is HIV/AIDs

A

virus
attacks immune system

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9
Q

what is influenza

A

virus
attacks respiratory system and causes muscle pain/headaches

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10
Q

what is tobacco mosaic virus

A

virus
discoloured leaves

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11
Q

what is blight

A

protist
affects leaves and potatoes

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12
Q

what is black sigatoka

A

fungus
leaf spots on banana plants that reduce yield

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13
Q

what is ringworm

A

fungus
growth in skin causes rash

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14
Q

what is athlete’s foot

A

fungus
growth under skin in feet

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15
Q

what is ring rot

A

bacteria
ring of decay in vascular tissue

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16
Q

what is malaria

A

protist
parasite in blood causes fever then death

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17
Q

what is bacterial meningitis

A

bacteria
infection of meninges (membranes around brain and spinal cord)

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18
Q

what is direct transmission

A

when communicable diseases are passed along by direct contact

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19
Q

what are examples of direct transmission

A

direct physical contact
faecal-oral transmission
droplet infection
spore transmission

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20
Q

what are the passive physical plant defences

A

cellulose cell wall
lignin thickening of cell walls
waxy cuticles
bark
stomatal closure

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21
Q

what is a callose

A

polysaccharide deposited in the sieve tubes to restrict entry of pathogens

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22
Q

what is a tylose

A

a swelling that fills xylem vessels that stops passage of water

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23
Q

what necrosis

A

cells are killed to prevent the spread of infection

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24
Q

what is a canker

A

produced by death of cambium creating a sunken lesion

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25
what are the chemical plant defences
terpenoids alkaloids tannins pheromones hydrolytic enzymes defensins
26
what does non-specific mean
fast acting same for any infection provides a general defense against most threats
27
what are the primary physical barriers
skin mucous membranes stomach acid lysozymes sebum expulsive reflexes
28
how does skin act as a barrier
epidermis contains keratinocytes so when cells dry out the cytoplasm becomes keratin
29
how do mucous membranes act as a barrier
contain ciliated epithelium
30
how does stomach acid act as a barrier
acidic conditions and digestive enzymes break down pathogens
31
what do lysozymes do
break down bacteria
32
what is a neutrophil
made in bone marrow multi-lobed nuclei in blood and tissue fluid short-term
33
what is a macrophage
made in bone marrow larger than neutrophils in body organs or lymph nodes travel in blood as monocytes
34
what is the inflammatory response
mast cells detect damage and release histamines so blood flow to area increases histamines cause capillaries to leak so phagocytes and clotting factors are released into wound phagocytes engulf bacteria and cellular debris platelets move out of capillary to seal wound
35
what is phagocytosis
pathogen detected by phagocyte pseudopodia engulf pathogen phagosome carries pathogen into cell lysosomes fuse with phagosome to make phagolysosome hydrolytic enzymes break pathogen down debris released via exocytosis foreign antigens can be presented on cell surface - APC
36
what are the three main stages of the primary immune response
1- phagocytosis + antigen presentation 2- cell mediated response (T-lymphocytes) 3- humoral immunity (B-lymphocytes)
37
what happens in the cell mediated response
antigens on antigen presenting cells bind to receptors of T-lymphocytes - CLONAL SELECTION causes T-cell to divide rapidly by mitosis - CLONAL EXPANSION can make either T-helper, T-memory or T-killer
38
what is a T-helper cell
release cytokines stimulate B cell development + phagocytosis
39
what is a T-killer cell
kill infected cells using cytotoxins
40
what is a T-memory cell
immunological memory in secondary response
41
what happens in humoral immunity
antigens on antigen presenting cells bind to receptors of B-lymphocytes - CLONAL SELECTION causes B-cell to divide rapidly by mitosis - CLONAL EXPANSION can make either plasma cells or B-memory
42
what is a plasma cell
release antibodies
43
what is B-memory cell
immunological memory
44
what is the structure of an antibody
flexible hinge region disulphide bridges antigen binding site light and heavy chains variable region - specific to antigen constant region - efficient for cloning + protein synthesis, binds to phagocytes
45
what is an opsonin
antibody attaches to antigens on pathogen surface - helps phagocyte engulf pathogen
46
what is an anti-toxin
neutralise toxins from pathogens
47
what is an agglutinin
two binding sites so bind to more than one pathogen at once so cross-links pathogens - 'agglutinates' them
48
what is the secondary response
B+T memory cells go through clonal selection and expansion quickly - more antibodies produced faster - immunological memory
49
what is an autoimmune disease
when the immune system attacks itself so B+T cells specific to our antigens are destroyed
50
what is active immunity
immune system activated - B+T mem cells
51
what is passive immunity
antibodies from mother or injection
52
what is natural immunity
gained when people acquire a disease normally
53
what is artificial immunity
deliberate exposure to an antigen
54
natural active
antigens enter naturally produce antibodies and specialised lymphocytes
55
natural passive
mother to foetus
56
artificial active
vaccines produce antibodies and specialised lymphocytes
57
artificial passive
immune serum body doesn't produce its own antibodies
58
what are the forms of antigens in a vaccine
dead pathogen inactive toxin antigen isolation live microorganism harmless pathogen
59
what is an epidemic
wide spread communicable disease in 1 country
60
what is an endemic
area specific disease
61
what is a pandemic
world-wide spread
62
what is herd vaccination
vaccinating lots of people to decrease spread in population
63
what is local vaccination
vaccinating only most at risk people
64
antibiotic resistance
A random mutation (DNA change) occurs in a single bacteria. Some mutations protect the bacteria against the antibiotic. These bacteria survive and divide to produce more bacteria containing the antibiotic-resistance gene.
65
how to prevent antibiotic resistance
The rotated use of different antibiotics Taking the full course of antibiotics Avoiding overuse of antibiotics

ocr a biology 🧬 (25 decks)

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