mini modules Flashcards
1
Q
What is a biome?
A
a general term embracing each region with its characteristic climate, day-length, topography, flora and fauna
2
Q
Where does a tropic rainforest occur?
A
where there is no dry season - all months have an average precipitation of at least 60 mm
3
Q
Where are true rainforests found?
A
between 10 degrees north and 10 degrees south of the equator
4
Q
What is the mean monthly temperature in a tropical rainforest?
A
exceeds 18 degrees celsius
5
Q
What does the average annual rainfall lie between in a tropic rainforest?
A
1750 - 3000 mm
6
Q
What percent of all living plant species reside in a tropic rainforest?
A
50%
7
Q
What is habitat fragmentation?
A
the process by which habitat loss results in a division of large, continuous habitats into a greater number of small patches of lower total area and which are isolated from each other
8
Q
What is habitat fragmentation caused by?
A
geological processes and climate change
9
Q
What is the worlds largest biome apart from the ocean?
A
boreal forest or taiga
10
Q
Where is the boreal forest found?
A
throughout the high northern latitudes, between tundra and temperate forest
11
Q
What are the winters and summers like in the boreal forest?
A
long and cold winters (5-8 months). short summers always less than 4 months
12
Q
What are the two major types of boreal forest?
A
southern - close canopy forest, northern - lignin woodland and sparse taiga
13
Q
What kind of places are temperate deciduous forests found?
A
in areas with warm moist summers and mild winters
14
Q
What are the typical trees in a temperature deciduous forest?
A
oak, maple, beech and elm
15
Q
What are the usually yearly levels of precipitation in the desert?
A
25 - 200 mm - some years none
16
Q
What percentage of the earth’s land is arid or semi-arid?
A
33%
17
Q
What are the three types of desert climates?
A
hot, mild, cold
18
Q
What are anthromes?
A
globally significant ecological patterns created by sustained interactions between humans and biomes
19
Q
What is an ecosystem?
A
whole community of living organisms in conjunction with non-living components of their environment
20
Q
What is primary productivity?
A
rate of biomass produced per unit area by plants
21
Q
What are the units for primary productivity?
A
Jm-2day-1, kgha-1 year-1, gCm-2 year-1
22
Q
What is gross primary productivity (GPP)?
A
total fixation of energy by photosynthesis
23
Q
What is autotrophic respiration (RA)?
A
proportion of energy fixed by photosynthesis lost by respiration
24
Q
What is net primary productivity (NPP)?
A
difference between GPP and RA - represents actual rate of production of new biomass available for consumption by heterotrophic organisms
25
What is secondary productivity?
rate of production of biomass by heterotrophs
26
What are the latitudinal trends in productivity?
closer to the equator there is a higher level of productivity
27
What is the term for organic matter produced by photosynthesis within ecosystem boundaries?
autochthonous
28
What is the term for organic matter imported from elsewhere?
allochthonous
29
Why is less biomass needed for the same NPP in continental shelf compared to cropland?
the whole algae photosynthesises but only the leaves of a tree do
30
What is the equation for consumption efficiency?
energy consumed (C)/energy available (T)
31
What is the equation for assimilation efficiency?
energy assimilated (A)/energy consumed (C)
32
What is the equation for growth efficiency?
energy fixed in tissues (P)/energy assimilated (A)
33
What are assimilation efficiencies like in herbivores?
low - around 10%
34
What are assimilation efficiencies like in carnivores?
high - can go up to 90%
35
How does mutualism occur with cleaner and client fish?
smaller fish establish a 'cleaning station'. larger fish come up to station for ectoparasite removal. the smaller fish picks off and eats the ectoparasites
36
How does mutualism occur with ants and fungi?
ants keep fungi in their nests to break down leaf materials into cellulose and lignin. they keep the fungus free from pests and moulds
37
How does mutualism work involving gut inhabitants?
microbial populations in the rumen of cows and sheep collaborate to break down cellulose. these microbial populations are fungi, bacteria and protozoa
38
How does interspecies competition work with paramecium?
All three species grew well alone, reaching stable carrying capacities in tubes of liquid medium.
P.aurelia and P.caudatum together. P.caudatum declined to the point of extinction.
P.caudatum and P.busaria together. Neither species suffered a decline to the point of extinction. Stable densities much lower than when grown alone – indicating competition
39
What is Gause's principle?
if two competing species coexist in a stable environment, then they do so as a result of niche differentiation
40
What is a population?
a group of organisms of one species that is usually separated in some degree from other groups of the same species by geographical or by some boundary
41
What is random spatial distribution?
variance is equal to the mean
42
What is contagious spatial distribution?
variance is greater than the mean
43
What is regular spatial distribution?
variance is less than the mean
44
What is the equation for rate of change of population over time?
intrinsic rate of increase x population
45
What occurs at carrying capacity (K)?
birth rate = death rate
46
What is the density dependent effect?
there is an inverse relationship between population density and rate of increase of a population
47
What is density independence?
percentage mortality stays the same with population increae
48
What is direct density dependence?
percentage mortality increases with population increase
49
What is inverse density dependence?
percentage mortality decreases with population increase
50
What is scramble competition?
resource is shared amongst all of the competing animals and shared would b equal and the mortality would raise immediately from 0 -100% when resource per capita becomes insufficient for survival
51
What is contest competition?
each successful animal gets what it requires. mortality increases with density
52
What are r-selected species?
potential to multiply rapidly - producing large numbers of progeny early in the life cycle
53
What are K-selected species?
organisms with different life histories survive where there is intense competition for limited resources
54
What is homeostasis?
maintenance of a relatively stable internal environment
55
What are features of the endocrine system?
wireless system, has specific target cell binding, hormones carried long distance in the blood, involuntary
56
What are features of the nervous system?
wired system, anatomical connection with target cells, neurotransmitters diffuse through short distances, voluntary/involuntary
57
What does the central nervous system divide into?
brain, brainstem and spinal cord
58
What is gyrification of the human cortex?
folding of the cortex
59
What are the two divisions of neural tissue in the CNS?
gray matter and white matter
60
What is gray matter?
primarily neuronal cell bodies
61
What is white matter?
myelinated neurites projecting from neurones
62
What happens in the somatic nervous system?
voluntary control, motor neurons to skeletal muscle
63
What happens in the autonomic nervous system?
no voluntary control, neurons to visceral organs
64
What is a neurite?
long, filamentous extensions responsible for propagating action potentials
65
What is an astrocyte?
a 'star-shaped' glial cell which supports neurone function and delivery fo molecules to/from the vasculature
66
When are astrocytes activated?
in response to injury, neuroinflammation or degeneration of the brain
67
What are microglia?
resident immune cells of the brain, surveying for pathogens and damaged material
68
What are myelinating glia?
they myelinate neurones by insulating them in multiple layers of sphingolipids
69
What are oligodendrocytes?
they myelinate multiple axons
70
What are Schwann cells?
they myelinate single axons
71
What are common model organisms in neuroscience?
rodents, zebrafish, zebra finch, fruit fly, nematode worms
72
How can intracellular recording be done?
intracellular electrode: measures internal voltage. extracellular electrode: measures extracellular voltage
73
What does the sodium-potassium pump exchange?
3 intracellular sodium ions for 2 extracellular potassium ions
74
What are the concentrations of ions in the extracellular fluid in mmol-1?
K+ = 2.5, Na+ = 145, Cl- = 90
75
What s the threshold stimuli?
-15 mV below resting potential
76
What is the absolute refractory period?
during the spike, a neurone cannot be stimulated
77
What is the relative refractory period?
during hyperpolarisation and afterpolarisation, a suprathreshold stimulus is required to trigger an action potential
78
What are the two key properties of voltage dependent ion channels?
ion specific and voltage sensitive
79
What region of the axon are action potentials triggered from?
the axon hillock
80
What is the threshold of the axon hillock?
the lowest across the cell
81
What are the two forms of synapses?
electrical and chemical
82
What are features of electrical transmission?
instantaneous, bidirectional
83
When do gap junctions close?
in response to elevated Ca2+
84
What are features of chemical transmission?
signal transduction is not facilitated through direct cell to cell contact, slower than electrical.
85
What defines a neurotransmitter?
synthesised in pre-synaptic neurone, can be released into the cleft and elicit a response
86
What synapses are most common in the brain?
axodendritic
87
What does axosomatic mean?
synapsing at the cell body
88
What does axoaxonic mean?
synapsing at the axon
89
What processes are found at the synaptic junction?
glial, especially astrocytes
90
What is the reserve pool of neurotransmitter vesicles?
synaptic vesicles that are loaded with neurotransmitter are initially tethered to the acton cytoskeleton by synapsin 1. reserve pool vesicles can be released from cytoskeleton by Ca2+ dependent phosphorylation of synapsin 1
91
What kinase phosphorylates synapsin 1?
protein kinase C and others
92
What is priming?
ATP dependent process which partially fuses the synaptic vesicles with the pre-synaptic membrane
93
What proteins facilitate priming?
SNARE proteins
94
Where is v-SNARE?
synaptic vesicle
95
Where is t-SNARE?
presynaptic terminal
96
What blocks fusion if Ca2+ is not bound?
synaptotagmin
97
What allows SNARE facilitated membrane fusion to occur?
calcium binding to synaptotagmin causes a conformational change
98
What endocytic protein coats synaptic vesicles?
clathrin
99
What facilitates scission of vesicles from membrane?
dynamin
100
What activates dynamin?
GTP -> GDP + Pi
101
What do botulinum neurotoxins do?
bind and cleave the c-terminal of t-SNARE SNAP25 by metalloprotease activity which results in failure of neurotransmitter fusion
102
What does the tetanus toxin do?
enter pre-synaptic membrane and bind and cleave synaptobrevins VAMP1/2 and can result in a loss of GABA release so there is overactivity of motor neurons
103
What is VGLUT?
vesicular glutamate transporter
104
What is VMAT?
vesicular monoamine transporter (serotonin, dopamine, adrenaline)
105
What is VachT?
vesicular acetylcholine transporter
106
What is VGAT?
vesicular GABA transporter
107
What is the most common excitatory neurotransmitter in the mammalian CNS?
glutamate
108
What transporter loads glutamate into synaptic vesicles?
VGLUT
109
What do astrocytes do to glutamate?
convert it to glutamine by glutamine synthetase which is secreted from astrocytes
110
How is GABA synthesised?
synthesised from glutamate by glutamic acid decarboxylase (GAD)
111
How is GABA and glutamate produced?
from alpha-ketoglutarate in the Krebs cycle
112
Can a single EPSP stimulate an action potential?
no, one is not enough to reach threshold. many are required to overcome threshold
113
What are the cys-loop receptors for?
acetylcholine, GABA, glycine and serotonin
114
What are glutamate receptors for?
glutamate, non-selective cations
115
What are the three categories of glutamate receptors?
AMPA, Kainate, NMDA
116
What ion blocks NMDA receptor channels at resting potential?
Mg2+
117
What are are NMDA receptors blocked and antagonised by?
blocked = Zn2+, antagonised = Pb2+
118
What is habituation?
learning to ignore harmful stimulus
119
What is sensitisation?
learning to avoid noxious stimulus
120
How do plants decide when to flower?
signalling from the leaves to the growing point - the shoot apical meristem
121
What is the signal to make the plant flower?
from many plants - day length - photoperiod
122
What is the signal to make the plant flower?
from many plants - day length - photoperiod
123
What do short day plants need?
long nights to flower
124
What's part of a basic flower structure?
sepal, petal, stamen, carpel
125
What's part of a basic flower structure?
sepal, petal, stamen, carpel
126
What is self-fertilisation?
pollination within the same flower
127
What does pollination between different flowers promote?
diversity
128
What is abiotic pollination done by?
wind and water
129
What is biotic pollination done by?
insects, birds, mammals
130
What visual markings do bees see?
blue or yellow but not red
131
What is the preference of pollinators for smell?
bees, butterflies and moths = sweet smells. beetles = yeasty, spicy, fruity smells
132
What is the reward of animal assisted pollination?
nectar, pollen, shelter, food and shelter for young
133
What are adaptations of pollen?
shape, stickiness and pollinia
134
What is pollinia?
a coherent mass of pollen grains that is the product of each anther lobe of some flowers
135
What are some adaptations of floral shape?
mimicry, long floral tube, specialised mechanisms
136
What are the specialised mechanisms of floral shape?
triggers, traps and narcotics
137
What is the shape of wind pollinated flowers?
feathery stigma, no petals or sepals, hanging anthers
138
What is epihydrophily?
when pollination happens at the surface of the water
139
What is hydrohydophily?
when pollination happens below the surface of the water
140
How do plants prevent self-pollination?
separation of sexes: structural, temporal, biochemical
141
What is herkogamy?
structural separation of the sexes within the flower
142
What is monoecy?
structural separation of the sexes within the plant
143
What is dioecy?
structural separation of the sexes as they are in different plants
144
In dioecy what does the female flower do?
pistillate
145
In dioecy what does the male flower do?
staminate
146
In monoecy what does the male flower have?
tassels
147
In monoecy what does the female flower have?
silks and cobs
148
What is protoandry?
anthers mature before stigma
149
What is protogyny?
stigma matures before anthers
150
What is heteromorphic incompatibility?
either short style, high anthers or long style, low anthers
151
What is homomorphic incompatibility?
self incompatibility at the S locus
152
What is the difference between sporophytic and gametophytic incompatibility?
gametophytic self incompatibility is determined by the genotype of gametes while sporophytic self incompatibility is determined by the genotype of the plant
153
When is inbreeding important?
shortage of pollinators, environmental uncertainty, weedy species, small colonising population
154
What happens when the pollen reaches the stigma?
hydration and germination and pollen tube is produced
155
What happens if the secretory zone is removed?
inhibits pollen tube growth in the transmitting tissue
156
What is involved in pollen fertilisation?
2 sperm cells, egg cell, polar nuclei, integuments
157
What happens after fertilisation?
embryogenesis
158
What happens during embryogenesis?
zygote (polar) -> basal cell + apical cell -> proembryo
159
What structures are in the mature embryo?
early cotyledons, torpedo and shoot apical meristem
160
Where do meristems take cells from?
all three layers - epidermis, ground tissue and vascular tissue
161
What are segment deletion mutants?
parts are missing - cotyledons and shoot meristems, hypocotyl and root
162
What are radial mutants?
abnormal cell layers occur in the plants
163
What are examples of monocotyledons?
cereals, grasses, lilies, palm trees
164
What are examples of dicotyledons?
oak, beech trees, daisies, beans, roses, strawberries etc
165
What does a monocot seed have?
endosperm
166
What does a dicot seed have?
cotyledons
167
How does fruit ripen?
as the seed develops - it is coordinated
168
How does fruit ripen in tomatoes?
chlorophyll is broken down, chloroplasts become chromoplasts, carotenoids are synthesised, starch converted to sugars, pectin broken down to soften the fruit
169
What is a fruit in relation to the plant system?
ovary
170
How does mechanical seed dispersal occur?
in witch hazel: explosive capsules. in filaree: driven burrowing
171
How do plants disperse their genes?
pollen dispersal (unfertilised) and seed dispersal (fertilised)
172
How does seed germination occur in barley?
seed takes up water -> embryo produces hormone = gibberellic acid (GA) -> stimulates aleurone to produce amylase -> amylase breaks down the stored starch into sugar -> sugar is used by embryo as energy source
173
What does emergence into light cause in plants?
opening out of cotyledons. apical meristems start making leaves
174
How do leaves grow?
shoot apical meristem drives all above ground movement, maintains a reserve population of rapidly dividing cells, leaves develop from the sides of the meristem
175
Where us the peripheral zone?
on the side of the meristem
176
Where is the rib meristem?
in the middle of the meristem
177
Where is the central zone?
between the peripheral zones
178
What is an invasive species?
a species introduced into an area outside their native range that can cause harm in that area
179
What did the plant Kudzu do?
introduced to USA and Asia in late 1800 as an ornamental plant. In 1900s was planted in USA to reduce soil erosion. Plant grew very rapidly and enshrouded the ground, shrubs, trees, houses, cars
180
What did the prickly pear do?
imported into Australia in 19th century as a natural agriculture fence. it became a widespread invasive species and rendered 40,000 km2 of farm land unproductive
181
How was the prickly pear stopped?
a mouth from South America whose larvae eats prickly pear was introduced in 1925 and almost wiped out population
182
What are examples of habitat modification?
grazing, browsing and rooting introduced mammals. aquatic introduced plants overgrow and shade out native plants
183
What can herbivory do?
often devastates native plant species, and sometimes entire communities
184
What is an example of herbivory?
european rabbits damaging native plants of islands
185
What is an example of a virus having an indirect and direct effect?
rabbits were grazing which encouraged wild thyme growth which the Large Blue butterfly fed on. virus was introduced and rabbit population fell to a low level. wild thyme was now not encouraged and so the Large Blue became extinct
186
What are some invasive species in the UK?
rhododendron, mink, signal crayfish, muntjac deer, himalayan balsam, japanese knotweed
187
What is one of the world's most invasive species according to the World Conservation Union?
Japanese Knotweed
188
How is Japanese Knotweed invasive?
has an invasive root system and strong growth can damage concrete foundations, buildings, flood defences and paving
189
How much does it cost to remove japanese Knotwood?
£70 million to eradicate it from 10 acres in 2012
190
What insect was released to combat Japanese Knotwood?
Japanese psyllid insect
191
What percentage of the population was living in cities at the turn of the 20th century?
15%
192
When do urban heat islands form?
when industrial and urban areas produce and retain heat
193
Why are do cities usually have higher surface temperatures?
as there is less vegetation and exposed soil, the suns energy is absorbed by buildings and asphalt
194
What can urbanisation cause environmentally?
highly fragmented, heterogenous and altered environments. also associated with declines in animal and plant richness, abundance and diversity
195
What is ruderal vegetation?
empty lots, abandoned farmland, and other green space is cleared but not managed
196
What are urban avoiders?
very sensitive to human habitat disturbances e.g. large mammals, old forest birds
197
What are urban adaptors?
frequently found in sub-urban matrix areas
198
What are urban exploiters?
dependent on human resources
199
How to help with light pollution?
Unnecessary lights extinguished or not installed
Spectrum chosen to minimise impacts (not uv or blue)
As bright as necessary for purpose
Directly only where needed
Only illuminated as long as necessary
200
How to help with light pollution?
extinguish unnecessary lights, direct only where needed, only illuminated as long as necessary
201
Are urban or rural health levels better?
urban
202
What is tillage?
agriculture by preparation of soil by mechanical agitation
203
What does primary tillage do?
loosens the soil and mixes in fertiliser and/or plant material, resulting in soil with rough texture
204
What does secondary tillage do?
produces finer soil and sometimes shapes the rows, preparing the seed bed
205
What are the positives of tillage?
loosens and aerates, mixes harvest residues, mechanically destroys weeds, dries the soil before seeding
206
What are the negatives of tillage?
soil loses nutrients and water storage ability, lessens cohesiveness of the soil inducing erosion, reduces microbes, eutrophication
207
What is drainage?
system by which water is drained on or in soil
208
What is intercropping?
growing two or more crops in proximity
209
What is resource partitioning?
planting a deep-rooted crop with a shallow-rooted crop or planting a tall crop with a shorter one that requires shade
210
What is temporal intercropping?
practice of sowing a fast-growing crop with slow-growing crop
211
What is relay intercropping?
second crop sown during the growth, near the onset of reproductive development, of the first crop
212
What is trap cropping?
planting crop nearby that is more attractive to pests than crop production
213
What is a repellent intercrop?
repelling crop masking the smell of production crop?
214
What is push-pull cropping?
mixture of trap cropping and repellent intercropping
215
What is grazing?
method of feeding in which a herbivore feeds on plants or grasses
216
What are the two types of plant defences against grazing?
constitutive or induced
217
When are constitutive defences present?
always
218
When are induced defences present?
produced or mobilised to the site where the plant is injured
219
What are long term effects of pesticides?
changes to habitat and food chain
220
What is one of the three major drivers of biodiversity loss?
fertilisers
221
In 2018, what percentage of globally consumed fish came from aquaculture?
62.5%
222
What are the main challenges faced by intensive aquaculture?
to reduce its ecological footprint, to reduce the risk of disease, to prevent the introduction of invasive species
223
How does Diplostomum sp. infect a fish?
Adult parasite within intestine -> parasite eggs released in faeces, miracidium hatches and penetrates snail -> asexual reproduction within snail -> cercaria penetrates fish -> metacercaria in eye lens -> fish eaten by definitive host -> adult parasite within intestine
224
What is proliferative kidney disease caused by (a seasonal salmon disease)?
PKX (unknown)
225
Why are fish parasites so common?
fish are abundant and diverse and aquatic medium is ideal for continuous parasite transfer
226
What is Gyrodactylus salaris?
small ectoparasitic worm - direct life cycle, rapid reproduction
227
What did Norway do to get rid of Gyrodactylus salaris?
rotenone - disrupts electron transport chain
228
What are methods of detecting fish parasites?
during food processing (candling/electromagnetic sensor), disease recognition/research (microbiology, molecular)
229
How to prevent fish parasites?
maintain optimal environmental conditions for the host, prevent introduction of infectious organisms, ensure optimal nutrition, minimise stress
230
What are some control measures for fish parasite?
biological - predation of intermediate hosts by other fish, cleaner fish, selective breeding. physical - increased flow rate, filtration, UV light sterilisation
231
What is epidemiology the study of?
nature, distribution, causation, transfer, prevention, control
232
What are some bacterial diseases?
whooping cough, meningitis, tetanus, tuberculosis, STDs
233
What are two major global bacterial diseases?
Mycobacterium tuberculosis and Vibrio cholerae
234
What is an opportunistic pathogen?
capable of causing damage and infection in a compromised host
235
What is an obligate pathogen?
causes damage and infection as part of its growth and replication
236
What is a facultative pathogen?
causes disease as one part of its life cycle or when in a different host
237
What is a commensal pathogen?
induces either no damage or clinically inapparent damage to the host but may elicit an immune response
238
What is an example of a obligate pathogen?
Mycobacterium tuberculosis, gram-positive, aerobe
239
What is an example of a facultative pathogen?
Vibrio cholerae, gram-negative, anaerobe
240
What is an example of an opportunistic pathogen?
Pseudomonas aeruginosa, gram-negative - present in people with cystic fibrosis
241
What is an example of a commensal pathogen?
Lactobacillus acidophilus, gram-positive
242
How are cystic fibrosis lung infections diagnosed?
sampling -> cough swab -> microbial growth -> pure culture -> pathogen identification -> antibiotic susceptibility or reference centre follow up -> treatment and management
243
How do we identify a strain of bacteria?
ribotyping, macrorestriction, PCR-fingerprinting, DNA sequencing
244
How do we identify a species of bacteria?
MLST - multilocus sequence typing
245
How does MLST work?
sequence several conserved genes, get approximately 500 base pairs from a PCR fragment, define genetic linkage between strains, globally searchable strain database
246
What are bacterial pathogen virulence factors?
aids host colonisation, allows immune evasion, host cell invasion or escape, host destruction
247
What can multiple virulence plasmids encode?
enterotoxins, haemolysins, pilli, urease
248
What is a microbiome?
loads of local niches interacting with each other
249
What are essential roles of the human bacteriome?
allows us to extract energy from food, produces essential vitamins, regulates immune system, regulates glucose levels and metabolism
250
Which pathogens always infect us?
obligate
251
Which pathogens can be beneficial and do not cause infection?
commensal
252
Which pathogens can sometimes be non-pathogenic?
opportunistic
253
What is dysbiosis?
any change to the composition of resident commensal microbial communities relative to the community found in healthy individuals
254
What can affect a healthy gut microbiome?
lifestyle, genetics, mode of birth, medical practices
255
How many different species of bacteria are in the human gut?
>1000
256
What are culture dependent sample methods?
selective agar used to grow certain types of microorganism
257
What are culture independent methods of sampling?
16S RNA gene - used to measure the evolutionary distance between organisms. whole genome sequencing
258
What are antimicrobials?
synthetics or natural compounds which exhibit selective toxicity by inhibiting microbial pathways without adversely affecting the host
259
Antimicrobials are classified according to similarities in what?
molecular structure, mechanism of action, spectrum of antimicrobial activity
260
What are antibiotics?
antimicrobial agents that are produced naturally by microorganisms such as certain species of bacteria and fungi
261
What do bacteriostatic agents do?
inhibit important biological processes - they have weak target binding and if removed the cell will continue growing
262
What do bactericidal agents do?
kill the cell - strong target binding, cell count remains constant but viable cell count decreases
263
What do bacteriolytic agents do?
kill and lyse the cell, releasing their cytoplasmic content - rupture cytoplasmic membrane, total and viable cell counts decrease
264
What antibiotics target cell walls?
beta-lactam antibiotics - they possess a beta-lactam ring which interferes with transpeptidation (leads to peptidoglycan synthesis)
265
What are examples of beta-lactam antibiotics?
penicillin and cephalosporins
266
What are nucleic acid synthesis inhibitors?
quinolones disrupt bacterial metabolism by interfering with bacterial DNA gyrase - preventing supercoiling of DNA
267
What is an example of a quinolone?
ciprofloxacin - used to treat urinary tract infections
268
What do protein synthesis inhibitors do?
bind with high affinity to 30S ribosomal subunit, resulting in ribosome misreading mRNA - aminoglycosides
269
What do tetracyclines do?
bind to 50S subunit causing partial inhibition of protein synthesis and resulting in imbalance of the proteome?
270
Why has Big Pharma abandoned antibiotics?
lack of financial incentive/profit, the last entirely new class of antibiotics was discovered in the late 1980s
271
What is the cost of developing new antibiotics?
$1.5 million
272
What has led to high level of antibiotic resistance?
misuse and overuse of antibiotics in medicine and agriculture, patients not taking antibiotics as described, poor infection control in hospitals
273
What are antimicrobial drug resistance mechanisms?
modification of the drug target, enzymatic inactivation, removal of the cell through efflux pumps, metabolic bypassing, decreased uptake, lifestyle changes
274
What did most bacteria resistant to penicillin contain?
80% contained penicillinase, a type of beta-lactamase enzyme which hydrolyses the beta-lactam in penicllin - encoded by blaZ gene
275
What are the three methods of horizontal gene transfer?
transformation, transduction, conjugation
276
How does transformation work?
uptake of naked DNA by bacteria
277
How does transduction work?
bacterial DNA transfer between bacteria
278
How does conjugation work?
direct DNA transfer between bacteria
279
How to fortify the gut microbiome?
prebiotics, probiotics and symbiotics
280
What are prebiotics?
a selectively fermented ingredient that results in specific changes in the composition of the gastrointestinal microbiota
281
What are probiotics?
live microorganisms which when administered in adequate amounts confer a health benefit on the host
282
What are symbiotics?
mixture of probiotics and prebiotics
283
Why are biofilms important for infection?
can penetrate deep into tissue, making their removal difficult - cells shedding from biofilm can cause systemic infection - can't be engulfed by phagocytes due to size
284
Why is parasitology important?
parasitism is highly successful and >50% of animals are parasites
285
What is a DALY?
disability adjusted life years
286
What is parasitology?
study of parasites from Animal and Protista kingdoms: protozoa, parasitic worms, arthropods, chordates
287
What is phoresis?
two symbionts travel together - no harm - no physiological or chemical independence
288
What is mutualism?
both partners benefit- no harm - association is not obligatory
289
What is commensalism?
usually only one partner benefits - no harm - association is not obligatory
290
What is parasitism?
one partner lives at the metabolic expense of another - harm - obligatory independence
291
What are the two types of location within a host for a parasite?
ectoparasite and endoparasite
292
What is a definitive host?
parasite reaches sexual maturity
293
What is an intermediate host?
parasite develops & often reproduces asexually
294
What is a paratenic host?
parasite undergoes no development but remains infective to another host
295
What is a reservoir host?
animal that harbours a parasite which can be transmitted to humans
296
What are characteristics of microparasites?
epidemic disease, specific resistance to infection, high reproductive potential
297
What are characteristics of macroparasites?
endemic disease, non-specific host resistance, low reproduction potential
298
What are examples of microparasites?
prions, viruses, bacteria, protozoa
299
What are examples of macroparasites?
flatworms (Platyhelminths), round worms (Nematoda), Arthropoda, Monogenea (direct life cycle), Digenea
300
What are Monogenea?
mostly fish parasites - single host life cycle, direct life cycle
301
What are Digenea - Schistosoma?
they have more than one host, infect humans, lives in veins around the colon, eggs live in faeces and get in water, intermediate host is a snail
302
What is a Nematoda - Trichinella spiralis?
can be acquired from a zoonotic infection, lives in microvilli of the gut, changes the anatomy of host cell to make it a 'nursery' for juvenile worm
303
What is Monogenean attachment?
posterior opisthaptor equipped with suckers, clamps, hooks and/or glands
304
What is Digenean attachment?
oral and ventral suckers
305
What is Cestode attachment?
scolex
306
How do microparasites feed?
absorb nutrients via cell surface
307
How do macroparasites feed?
surface browsing, blood feeding, bulk tissue feeding, nutrient uptake across the body wall
308
What is the life cycle of a Polystoma (blood feeder)?
dimorphic life cycle (two different adult morphs)
309
What are problems associated with blood feeding?
waste products of blood digestions (haematin etc), lack of B vitamins, clotting agents, exposure to host's immune system
310
What are morphological adaptations of parasites?
increased body surface, modified mouthparts
311
What are physiological and behavioural adaptations?
symbiotic micro-organisms to counteract vitamin B deficiency, production of anticoagulants, acidification of host's gut through secretion of H+, migration along the host's gut
312
What is premunition?
host recovers form disease and is resistant to reinfection but some parasites remain and reproduce at a slow rate
313
What is concomitant immunity?
parasite elicits protection against re-infection, but parasite itself remains unaffected by immune response
314
How do parasites evade the host's immune response?
antigen disguise, antigen polymorphism, shedding antigens, immunomodulation of host (causing lymphocytes to produce wrong cytokines)
315
What is oviparous reproduction?
eggs released into the environment and develop outside parent's body
316
What is ovoviviparous reproduction?
encapsulated embryos develop within parent's body
317
What is viviparous reproduction?
embryos develop within parent's body (no egg shell)
318
What are hermaphrodites?
occurrence of both sexes in the same individual
319
What are advantages of being a hermaphrodite?
increases chance of finding a mate, increases egg output, potential for self-fertilisation
320
What is protandry?
male organs develop before female
321
What is protogyny?
female organs develop before male
322
What are the types of transmission?
contact transfer, ingestion of intermediated or paratenic hosts, release of eggs, free living larvae
323
What does Dicrocoelium dendriticum do?
parasite manipulates behaviour of the ant - infected ant migrate up blade of grass until they reach the top then they do a handstand and remain in that position all day to be eaten by a goat. Three hosts - goat, ant, snail
324
What does taxoplasma gondii do?
if mice/rats are infected they lose their fear of cats- then cats get infected (only definitive host)
325
What percentage of humans that have taxoplasma gondii are asymptomatic?
15-85%
326
How can toxoplasma be transmitted?
faecal-oral from cat, oral-raw meat/unpasteurised milk, blood transfusions
327
For parasites to adapt they have to respond to what?
discontinuity in space and time, host immunity, host evolution
328
Why are parasite life cycles so complex?
greater niche space for reproduction, increase the likelihood for transmission
329
What is the oldest parasite?
> billion years, mitochondrium - ancient bacterium transformed into mutualist
330
What is the Red Queen dynamic?
hosts and parasite much evolve quickly to keep from falling behind and going extinct
331
What are medicinal uses of parasites?
maggots - used to clean wounds, secrete antimicrobial. whipworms - parasite worms may prevent Crohns disease. worms vs asthma - probiotic worms
