Module 4 - Biodiversity, Evolution and Disease Flashcards
1
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Active immunity
A
Resistance in an organisms that has developed through production of specific antibodies in response to pathogen. Provides long-lasting immunity as memory cells are produced
2
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Agglutinins
A
Chemicals that cause pathogens to aggregate together, aiding phagocytosis. Antibodies can act as agglutinins
3
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Antibiotic
A
Chemical/compound produced by living organism that kills/prevents growth of bacteria
4
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Antibiotic-resistant bacteria
A
Bacteria that mutate to become resistant to an antibiotic, survive & reproduce rapidly, passing on their antibiotic resistance
5
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Antibodies
A
Immunoglobulins produced by B-lymphocytes in response to specific antigen, triggering immune response
6
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Antigen
A
Chemical presents on surface of cell that induces an immune response
7
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Antigen-presenting cell
A
Macrophage that displays foreign antigens
8
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Anti-toxins
A
Chemicals produced by white blood cells that neutralise toxins released by pathogens
9
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Artificial active immunity
A
Production of antibodies by immune system following exposure to weakened attenuated/dead pathogens e.g. vaccination
10
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Artificial passive immunity
A
Immunity acquired from the administration of specific antibodies from another organisms e.g. vaccination
11
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Athlete’s foot
A
Form of ringworm in humans, affects feet, cracking and scaling of the skin
12
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Autoimmune disease
A
Condition which the immune system attacks & destroys healthy body tissue e.g. arthritis
13
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Bacteria
A
Prokaryotic cells that have cell walls but lack organelles, some bacteria are pathogenic, producing toxins that damage host cells
14
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Bacterial meningitis
A
Severe form of meningitis caused by bacterial infection of meninges, complications of bacterial meningitis include septicaemia, symptom of this rash of purple discolouration that doesn’t fade when a glass is pressed against it
15
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B effector cells
A
Type of B lymphocyte that divides to form plasma cells
16
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Black sigatoka
A
Fungal disease in tomatoes cause by Mycosphaerella fijiensis hyphae of which penetrate & digest host leaf cells turning them black
17
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B lymphocytes
A
Lymphocytes that mature in bone marrow, 3 main types, plasma cells, B effector cells & B memory cells
18
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B memory cells
A
B lymphocytes that provide immunological memory
19
Q
Callose
A
Plant polysaccharide contains β-1,3 & β-1,6 linkages between glucose molecules, it is deposited between the cell walls & cell membrane in cells adjacent to infected cells serving as defence again pathogens, also found in cell walls of infected cells & plasmodesmata between infected cells
20
Q
Chitinases
A
Enzymes that degrade chitin in fungal cell walls
21
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Clonal expansion
A
Mass proliferation of specific antibody-producing cells
22
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Clonal selection
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Identification of an antibody-producing cell with complementary receptors to the shape of specific antigen
23
Q
Clostridium difficile
A
Type of bacteria found in gut of some individuals which is resistant to most antibiotics
24
Q
Communicable disease
A
Disease that is caused by pathogen & transmitted directly between organisms
25
Cytokines
Cell-signalling molecules produced by mast cells in damaged tissue, attract white blood cells to site of damage
26
Direct transmission
Transfer of a pathogen directly from 1 organism to another, can occur via direct contact/ingestion/sharing contaminated needles
27
Epidemic
Rapid rise in incidence of communicable disease at local/national level
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Expulsive reflexes
Coughs/sneezes initiated upon irritation of respiratory tract, remove microorganism-containing mucus from gaseous exchange system
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Fungi
Eukaryotic,. Digest & destroy cells & produce spores that can spread rapidly between organisms
30
Glucanases
Enzyme produced by plants that decompose glucans, polysaccharides found in oomycete cell walls
31
Histamine
Chemical produced by mast cells in damaged tissue, makes blood vessels dilate & cause their walls to become leakier
32
Human Immunodeficiency Virus (HIV)
Infectious virus that destroys T helper cells, weakening immune system of body. HIV makes an individual more susceptible to opportunistic infections & can lead to AIDS
33
Indirect transmission
Transfer of pathogen organisms via fomites/vectors/droplet infection/soil contamination
34
Inflammation
Localised response of vascular tissue to pathogens/damage/irritants, characterised by pain/redness/heat/swelling
35
Influenza
Common vital infection caused by family of viruses, Orthomyxoviridae, destroys ciliated epithelial cells in gaseous exchange system, exposing airways to secondary infection
36
Interleukins
Cytokines produced by T helper cells that stimulate B cells
37
Lymphocytes
White blood cells that contribute to the specific immune response
38
Lysosome
Membrane-bound organelles that contain hydrolytic enzymes
39
Malaria
Disease caused by protoctista Plasmodium, lives within 2 hosts, mosquitoes & humans, causes recurrent episodes of fever, can be fatal
40
Mast cells
Specialised cells in connective tissue that are important in the inflammatory response, releasing histamines & cytokines
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MRSA
Type of bacteria that is resistant to the antibiotic methicillin
42
Mucous membranes
Membranes lining body cavities that secrete a sticky mucus
43
Natural active immunity
Production of antibodies by immune system following infection
44
Natural passive immunity
Immunity acquired by infant mammal when antibodies are transferred through the placenta & the colostrum from the mother
45
Non-specific defences
Defences that are always present & are the same for all organisms e.g. skin, blood clotting, inflammation, mucous membranes
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Opsonins
Chemicals that bind to and tag foreign cells, making them easily recognisable to phagocytes
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Passive immunity
Resistance in an organism acquired via the transfer of antibodies, provides short-term immunity as no memory cells are produced
48
Pathogen
Disease-causing microorganism, includes bacteria, viruses, fungi & protoctista
49
Penicillin
First conventional, effective & safe antibiotic derived from mould Penicillium chrysogenum, discovered by Alexander Flemming
50
Personalised medicine
Form of medical care that enables doctors to provide healthcare that is customised to an individual's genotype
51
Phagocytes
Specialised white blood cells that engulf & destroy pathogens, 2 types: neutrophils & macrophages
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Phagocytois
Process by which phagocytes engulf & destroy pathogens
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Phagolysosome
Vesicle within a phagocyte formed by fusion of phagosome & lysosome
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Phagosome
Vacuole inside a phagocyte, which a foreign particle is engulfed
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Plasma cells
B lymphocytes that produce antibodies specific to a particular antigen
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Potato blight
Disease caused by fungi-like protoctist Phytophthora infestans whose hyphae penetrate host cells, causing collapse & decay of leaves/fruit/tubers, also known as tomato blight
57
Primary immune response
Response of the immune system to a pathogen when it is 1st encountered, small no. of antibodies are produced slowly
58
Protoctista
Group of eukaryotic, single-celled microorganisms that may cause disease, digest cells & use the cell contents to reproduce
59
Ring rot
Bacterial disease in tomatoes/potatoes/aubergines, result in damage to leaves/fruit/tubers, caused by Clavibacter michiganensis bacterium
60
Ringworm
Fungal disease that affects mammals, causing grey-white circular crust lesions on the skin
61
Secondary immune responses
Response of the immune system to a pathogen when it is encountered for a 2nd(3rd,4th etc) time. Immunological memory gives rapid production of large no. of antibodies
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Synthetic biology
Design & construct of new biological entities, reconstruction of pre-existing natural biological systems
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T helper cells
T lymphocytes with CD4 receptors on cell surface membrane, these bind to antigens on antigen-presenting cells & secrete interleukins
64
T killer cells
T lymphocytes that produce perforin, destroying pathogens with specific antigen
65
T lymphocytes
Lymphocytes that mature in thymus gland, 4 main types: T helper cells, T killer cells, T memory cells & T regulator cells
66
T memory cells
T lymphocytes that provide immunological memory
67
Tobacco Mosaic Virus (TMV)
Virus that infects many species of plant, damages leaves/flowers/fruit, stunts plant growth
68
T regulator cells
T lymphocytes that regulate the immune response by supressing other T cells & maintaining tolerance to self-antigens
69
Tuberculosis (TB)
Bacterial disease caused by Mycobacterium tuberculosis & M. bovis, damages lung tissue, weakens immune system
70
Vaccination
Deliberate exposure of an individual to antigens from pathogen to provide artificial active immunity
71
Vector
Living/non-living agent that transmits a pathogen between organisms
72
Viruses
Non-living infectious agents that invade host cells & take over cell metabolism, replicating within them.
73
Adaptation
Feature of an organism that increases its chance of survival in its environment, may be anatomical/physiological/behavioural
74
Belt Transect
Line along sampled area, quadrats place at intervals to determine abundance & distribution of organisms in an ecosystem
75
Binomial system
Universal system of naming organisms, made up of 2 parts, 1st gives the genus & 2nd the species
76
Biodiversity
Variety of living organisms in an ecosystem
77
Charles Darwin
Scientist who developed theory of evolution by natural selection
78
Classification
Organisation of organisms into groups
79
Community
All of populations of different species living together in a habitat
80
Conservation
Maintenance of ecosystems & biodiversity by humans in order to preserve Earth's resources
81
Continuous variation
When a characteristic can have any value within a given range e.g. height/mass/HR
82
Conservation on Biological Diversity (CBD)
Treaty that promotes sustainable use of & maintenance of biodiversity, 1/3 Rio Conventions
83
Conservation on International Trade in Endangered Species (CITES)
Treaty that regulates trade of plants & wild animals across international borders
84
Convergent evolution
Process by which unrelated species evolve similar traits due to exposure to similar environments/selection pressures
85
Countryside Stewardship Scheme (CSS)
Scheme in England that aimed to provide financial incentives to farmers to enhance & conserve environment. Replaces by Environmental Stewardship Scheme (ESS)
86
Discontinuous Variation
When a characteristic can only take certain values e.g. sex/eye colour/blood group
87
Domain
Highest taxonomic rank, are 3 domains:
Archaea
Bacteria
Eukaryota
88
Evolution
Gradual change in allele frequency within a population over time, occurs due to natural selection
89
Ex Situ conservation
Type of conservation that takes place outside organism's natural habitat e.g. Zoos
90
Fossil
Remains of dead organisms found in rocks, millions of years old
91
Fungi
Biological kingdom consisting of mushrooms, yeast & moulds
92
Genetic biodiversity
Measure of variety of genes that make up a species
93
Habitat biodiversity
Measure of no. of different habitats found within an area
94
In situ conservation
Takes place within an organism's natural habitat e.g. wildlife reserves
95
Interspecific variation
Differences between members of different species
96
Intraspecific variation
Differences between members of the same species
97
Keystone species
Species which has an unexpectedly large effect on environment & its crucial for maintenance of biodiversity
98
Kick-sampling
Method used to sample organisms living on bed of river, involves disturbing an area of river bed before placing net downstream to capture released organisms
99
Kingdom
2nd highest taxonomic rank, are 5:
Prokaryotae
Protoctista
Fungi
Plantae
Animalia
100
Line transect
Line along sampled area, species touching transect at regular intervals are recorded to determine abundance & distribution of organisms in ecosystem
101
Monoculture
Growth of 1 crop in given area
102
Natural selection
Process by which frequency of 'advantageous' alleles gradually increases in population's gene pool over time
103
Non-random sampling
Sample isn't chosen randomly, 3 types:
Opportunistic
Stratified
Systematic
104
Opportunistic sampling
Involves drawing sample from part of population that is conveniently available
105
Phylogenetic tree
Diagram used to show evolutionary relationships between organisms
106
Phylogeny
Evolutionary relationship between individuals/groups of organisms
107
Pitfall trap
Device used to catch small ground surface invertebrates, consists of a container buried beneath ground & roof structure
108
Pooters
Device used in collection of small insects, consists of 2 tubes, 1 connecting the holding chamber to a mouthpiece, with filter & other to an inlet tube
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Prokaryotae
Biological kingdom consisting of unicellular prokaryotes (bacteria)
110
Proportion of polymorphic gene loci
Measure of genetic biodiversity, calculate using:
Proportion of polymorphic gene loci=no. f polymorphic gene loci/total no. of loci
111
Protocistsa
Biological kingdom consisting of unicellular eukaryotes
112
Quadrat
Square grid of known area, used in sampling to determine abundance or organisms in a habitat, 2 types:
Point quadrat
Frame quadrat
113
Random sampling
Used to avoid bias e.g. creating square grid & generating random coordinates
113
Seed bank
Storage of seeds to preserve genetic material
114
Selections pressures
Environmental factors that drive evolution by natural selection & limit population sizes e.g. competition/predator/disease
115
Simpson's Index of Diversity (D)
Measurement of diversity that considers both species richness & evenness
D=1-∑(n/N)²
116
Spearman's rank correlation coefficient
Statistical test used to determine relationship between 2 variables
117
Species biodiversity
Measure of species richness & evenness
118
Species evenness
No. of individuals of each species living together in a community
119
Species richness
No. of different species found within an area
120
Stratified sampling
Populations are divided into strata & random sample is taken from each proportional to its size
121
Student's t-test
Statistical test used to analyse whether there is a significant difference between means of data values of 2 populations
122
Sweep nets
Funnel-shaped net used to catch insects & other small animals
123
Systematic sampling
Samples are taken from different regions of a habitat
124
Taxon
Each group within a phylogenetic classification system
125
Taxonomic hierarchy
Arrangement of organisms into successive levels of classification
126
3-domain system
Method of classification in which organisms are categorised into 3 domains & six kingdoms
Carl Woese
127
Tullgren funnel
Device used to extract living organisms from soil sample
128
Variation
Differences between individuals due to genes/environment/combination of both
129
Name 4 groups of pathogens that can cause communicable diseases
*Bacteria
*Fungi
*Protoctista
*Viruses
130
How does Mycobacterium tuberculosis cause disease
1.Triggers inflammatory response by infecting phagocytes in lungs
2.Infected phagocytes are sealed in waxy-coated tubercles so bacteria remain dormant, 1st infection has 0 symptoms
3.If another factor weakens immune system, bacteria become active & destroy lung tissue
131
How does HIV result in symptoms of AIDS
1.Attachment proteins bind to complementary CD4 receptor on TH cells
2.HIV particles replicate inside TH cells, killing/damaging them
3.AIDS develops when there are too few TH cells for immune system to function
4.Individuals cannot destroy other pathogens & suffer from secondary diseases/infections, may cause death
132
How does the Tobacco Mosaic Virus cause disease
Affected plants, mainly transmitted via infected sap
Contains ssRNA, directly transcribed by host cell to assemble new virions
Virions enter other cells via plasmodesmata, then xylem & phloem
Caused stunted growth & mottled leaves
133
How does the influenza virus cause disease
Transmitted via, droplet infection, contact with mucus containing virus, zoonotic infection, contact with fomites
Injects viral RNA into ciliated epithelial cells of throat & lungs. Viral RNA hijacks cell biochemistry to produce new virions, cell lysis releases virions
5-7 days of headache, cough, sneeze, sore throat, vomiting, fever, muscular/joint pain
134
What causes Malaria
Female Anopheles mosquito acts as vector for Plasmodium spp. protoctista when it transfers saliva to another organism during feeding.
Parasite reproduces asexually in RBC in liver causing lysis
135
What causes potato/tomato late blight
Protoctista Phytophthora infestans behaves similarly to fungus
Mainly transmitted via spores
136
What causes ring rot in potatoes
Sepedonicus subspecies of bacterium, Clavibacter michiganensis
Mainly transmitted by planting infected seeds/contact with fomites
Plant-to-plant transmission is rare
137
What cause bacterial menigitis
Meginignococcal bacteria A,B,C,W,X,Y,Z
Also caused by pneumococcal bacteria & haemophilus influenzae type b (Hib) bacteria
Affects meninges - protective tissue around brain
Transmitted by droplet infection & direct contact with saliva
Usually spread by carriers of bacteria who aren't ill & occasionally by individuals with meningitis
138
3 fungal infections
*Black sigatoka
*Ringworm
*Athlete's foot
139
Black sigatoka
Mycosphaerella fijiensislack causes leaf-spot disease in banana plants
140
Ringworm
40 types of fungi cause it
Transmitted by contact with fomites, zoonotic infection, direct contact with infected individuals
Particularly affects cattle
141
Athlete's foot
Caused by a range of fungi
can affect hands/nails
142
How are communicable pathogens transmitted directly
*Inhalation
*Skin-to-skin contact/exchange of fluids
*Penetrate skin actively using enzymes/passively through wounds, hair follicles/sweat glands
143
How are communicable pathogens transmitted indirectly
*Consumption of contaminated food/drink
*Via vector
*Spores
144
How do living conditions affect disease transmission?
*Overcrowding increases direct transmission
*Climate determines which organisms can survive
*Social factors influence how quickly people are treated which can increase/decrease direct transmission
145
4 physical barriers to pathogens entry in plants
*cellulose cell wall
*lignified layer
*waxy upper cuticle
&old vascular tissue blocked to prevent pathogens spreading inside the plant
146
Mechanical responses to infection in plants
*Guard cells close stomata
&Thick polysaccharide callose produces & deposited between cell wall & plasma membrane to increase entry distance/limit spread
147
Necrosis
Injury activates intracellular enzymes in plants that kill cells near the site of infection to prevent pathogen from spreading, this of woody tissue=canker
148
Chemical defences plants use against pathogens
*Terpenoids-essential oils, act as antibacterial e.g. methanol's
*Phenols-inhibit insects from attacking by interfering with digestion e.g. tannin
*Alkaloids-deter herbivores from feeding cause they taste bitter e.g. caffeine
*Defensins-inhibit transport channels e.g. cysteine-rich proteins
*Hydrolytic enzymes-break down cell wall of invading organism e.g. chitinase
149
Barriers to infection in animals
*Skin is tough keratin layer
*Blood clotting, prevents from entering through skin
*Hydrochloric acid in stomach kills bacteria
*Harmless bacteria in gut/skin surface, interspecific competition with pathogens
*Mucous membranes trap pathogens & secrete antimicrobial enzymes
150
Ways the nonspecific immune system responds to infection
*Inflammation
*Phagocytosis
*Digestive action of lysozymes
*Production of interferon (antiviral agent)
151
Process of inflammation
1.Damaged vessels release histamines, causing vasodilation
2.Blood flow & permeability of vessels increase
3. WBC & Plasma move into infected tissue
152
How does blood clotting occur
1.Blood platelets form plug & release chemicals that enhance clotting e.g. thromboplastin
2.Prothrombin changes into thrombin, active form
3.Fibrinogen changes into insoluble fibrin which covers wound
153
2 types of WBC involved in phagocytosis
Neutrophils
Macrophages (can become antigen-presenting cells)
154
How does phagocytosis destroy pathogens
1.Phagocytes move towards pathogen, may be marked with opsonin
2.Phagocyte engulfs pathogen via endocytosis to form phagosome
3.Phagosome fuses with lysosome (phagolysosome)
4.Lysozymes digest pathogen
5.Phagocyte absorbs products from pathogen hydrolysis
155
Role of antigen-presenting cells
Macrophages display antigen from pathogen on surface, enhances recognition by TH cells (which cannot directly interface with pathogens/antigen in body fluid)
Secrete cytokines that are involved in stimulating specific immune response
156
Lysozymes
Digestive enzymes, found in lysosomes, damage bacterial cell walls, causing osmotic lysis
157
How to prepare blood to be vies under a microscope
1.Smear drop onto slide using spreader held at 45°
2.Add Leishman stain then buffer
3.Rinse
158
Types of specific immune response
*Cell-mediated
*Humoral
159
Process of cell-mediated response
1.Complementary TH lymphocytes bind to foreign antigen on APC
2.Cell signalling via secretion of interleukins stimulates:
a) clonal expansion of complementary TH cells, become memory cells/trigger humoral response
b) clonal expansion of cytotoxin T cells, secrete enzyme perforin to destroy infected cells
160
Process of humoral response
1.Complementary TH lymphocytes bind to foreign antigen on APTC
2.Release cytokines that stimulate clonal expansion of complementary B lymphocytes
3.B cells differentiate into plasma cells
4.Plasma cells secrete antibodies with complementary variable region to antigen
161
Structure & function of B lymphocytes
Many specific receptors & immunoglobulins on surface
B cells differentiate into plasma cells to secrete antibodies
162
Structure & function of T lymphocytes
3 types of T cells:
-T helper=secrete cytokines
-T killer=secrete perforin
-T regulator=suppress other immune cells to prevent autoimmune disease
163
Structure of antibody
Quaternary structure:
2 'light chains' held by disulphide bridges,
2 longer 'heavy chains'
Binding sites on variable region of light chain have specific tertiary structure complementary to antigen
rest of molecule is constant region
164
How do antibodies lead to destruction of pathogens
-Agglutinins form antigen-antibody complexes to enhance phagocytosis
-Activation of complement
-Opsonin mark microbes for phagocytes
-Antitoxins make toxins insoluble via precipitation/neutralisation
165
What are T memory cells
-Produced from the primary immune response
-Remain in low levels in blood
-Can divide rapidly by mitosis if organism encounters the same pathogen again
166
Differences between primary & secondary response
Secondary response:
-Faster rate of antibody production
-Shorter time lag between exposure & antibody production
-Higher concentration of antibodies
-Antibody level remains higher after secondary response
-Pathogen usually destroyed before any symptoms
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