BIOC1010-QALLCSV Flashcards
Define microbiology
The study of microorganisms which are not visible to the naked eye (
What size is the Tobacco Necrosis Satellite Virus?
17nm
Order from smallest to largest (with sizes): Influenza, Pox, Tobacco Necrosis Satellite, Polio
Tobacco Necrosis Satellite (17nm), Polio (28nm), Influenza (100nm), Pox (200nm) —> all viruses
What things are shared between macrobes and protists in the eukaryote class?
Fungi and Algae occur in both classes
What technique do we use to sequence a phylogenetic tree?
16S Ribosomal RNA sequencing
What is a phylogenetic tree?
Branching diagram showing inferred evolutionary relationships among biological species
How many bacteria are estimated to be present in a lecture theatre and what biomass would they have?
10^16 bacteria, weigh only 100kg
What is a difference in biodiversity between microbes and macrobes?
Microbes all appear very similar but have very different phylogeny, macrobes appear very different but stem from the same branch of a phylogenetic tree
What is the size difference between prokaryotic and eukaryotic cells?
Prokaryotic: 1-2micrometers, Eukaryotic: 30-100micrometers
What are the key differences between prokaryotes and eukaryotes in their packaging of the DNA genome?
E: Linear, protein-like chromosomes attached to microtubules and packaged in nucleus. P: Aggregated DNA mass (Nucleoid), circular plasmids, no; nuclear membrane, chromosomes, mitosis/meiosis, microtubules
What is an example of a eukaryotic and prokaryotic cell?
E: Saccharomyces Cerevisae (yeast), P: Heliobacterium Modesticaldum
Why is Gemmata obscuriglobis an exception to the norm?
It is a planctomycete (prokaryote) with a nuclear envelope surrounding its nucleoid
What is Chlamydomonas and how big is it?
Green algae found in stagnant water, 10micrometers long - ion channels activated by light
What are the difference in genome complexity between eukaryotes and prokaryotes?
E: larger (10-10,000MBp), more protein coding genes (6,000-40,000), P: smaller, circular (2-10MBp), fewer protein coding genes (1,000-5,000)
How many protein coding genes are then in eukaryotes and prokaryotes?
E: 6,000-40,000. P: 1,000-5,000
What is different between organelles in prokaryotes and eukaryotes?
Prokaryotes have no organelles! Although occasionally have internal membrane systems with specialised functions
What organelles are (almost) universal in a eukaryote?
Mitochondria
Which organelles are present only in plants/algae/protists?
Plastids (along with many others…)
Where does respiration occur in a prokaryote?
In the plasma membrane
Where does aerobic respiration occur in Saccharomyces cerevisiae?
On the inner membrane of the mitochondria is where ATP synthesis and aerobic respiration occurs
Are chloroplasts present in prokaryotes? And what is their function?
Absent in prokaryotes, they are the site of photosynthesis
Which 3 processes occur during photosynthesis?
Light absorption, O2 evolution, CO2 fixation
What are the latin and common names for 3 photosynthetic cells?
Chlamydomonas (Green single cell algae), Spirogyra (filamentous green algae), Plagiomnium (moss)
What is an example of a bacteria with a specialised internal membrane system (latin and normal names)?
Synechocystis sp. - cyanobacterium
What is the specialised membrane used by cyanobacterium for respiration/photosynthesis?
Thylakoid membrane, site of photosynthesis and respiration, remains in contact with cytoplasm
What is the endosymbiotic theory?
Mitochondria/Chloroplasts are descendants of free-living bacteria that formed an endosymbiosis with a protoeukaryote 1-2bn years ago
What are the free-living bacteria which are believed to be the ancestors for mitochondria and chloroplasts?
Mitochondria - alpha-proteobacterium. Chloroplasts - Cyanobacterium
What type of cell was the cyanobacterium/protobacterium believed to have endosymbiosis with?
Archaeon (Archaea)
What is an example of something that both prokaryotes and eukaryotes have?
Ribosomes
What is the difference between ribosome structure in prokaryotes and eukaryotes?
E: 80S ribosome in cytoplasm, 70S ribosome in organelles. P: only 70S ribosomes
What is the S in 70S ribosomes an indicator of?
S is the Svedberg unit, a measure of size and density
What are the two different antibiotics that inhibit ribosomes?
Chloroamphenicol inhibits only 70S ribosomes, Cycloheximide inhibits only 80S ribosomes
What is the difference in flagella between eukaryotes and prokaryotes?
E: microtubule bundle, surrounded by membrane sheath P: single flagellin filament
What is an example of a prokaryote that has a single flagellin filament?
Ralstonia Eutropha (Gram-negative soil bacterium)
What are 2 examples of a eukaryote with microtubule flagella bundles?
Tetraselmis (phyotplankton), Chlamydomonas
What is the mechanism of the flagella in a prokaryote?
Rigid flagellum which rotates/spins, controlled by rotary motor
What is the mechanism of the flagella in a eukaryote?
Dynein motor, microtubules arranged in 9 + 2 pattern
What is the difference in cell wall between eukaryotes and prokaryotes?
E: cell wall made of cellulose (plants) or chitin (funghi). P: cell wall made of peptidoglycan (bacteria) or others (archaea)
What are the advantages and disadvantages of a cell wall?
A: Rigidity, defined shape, protection. D: no amoeboid movement, no phagocytosis
What is the difference in structure between gram positive and gram negative bacteria?
Gram +ve: thick peptidoglycan layer, no outer cell membrane. Gram -ve: thin peptidoglycan layer, periplasmic space, crenated outer membrane
Name two important scientists
Pasteur and Koch
Describe some key features of Anthrax
Bacillus Anthracis, highly infectious, skin pustules, fever, nausea, endospores are very resistant - survive 100s years
Who were the first two scientists to believe in the concepts of microorganisms?
Lucretius (invisible living creatures caused disease), Antony van Leeuwenhoek (visualised using microscopes)
Who disproved the notion that bacteria arise by spontaneous generation?
Louis Pasteur, heating boiling flask, dipped in microbes, bend
What were Koch’s Postulates?
rules for confirming a causal link between microorganisms and disease
Who invented the dilution method for studying bacterial cultures?
Joseph Lister
What was the first iteration of the Agar plate?
A slice of boiled potato
Who first suggested the use of agar over gelatin as a setting agent?
Fannie Hess, researchers wife
Who invented the petri dish?
Richard Petri
How can bacterial strains be maintained (3)?
regular sub-culture to fresh medium, frozen storage, freeze drying
What are some examples of culture collections?
ATCC, PCC, NCTC, NCIB
What is the difference between macronutrients and micronutrients?
macronutrients are needed in large amounts, micronutrients in trace/lesser amounts
How do autotrophs get their carbon?
Inorganically in the form of CO2, provides Carbon for biomass
How do heterotrophs get their carbon?
In the form of organic compounds such as glucose - provides energy for respiration/fermentation and biomass
Are phototrophs/chemotrophs examples of autotrophs or heterotrophs?
Autotrophs
Heterotrophs gather their energy from organic carbon compounds, where do autotrophs gather their energy from?
Phototrophs/chemotrophs use energy from light/chemicals to oxidise electron donors e.g. H2S, NH3, light
What are the inorganic forms of phosphorous/sulfur/nitrogen used by bacteria?
Typically in ionic form e.g. NH4+, NO3-, N2, PO43-, SO42-, H2S, S
What is the difference between defined/undefined (complex) media?
Defined: assembled from a specific list of chemicals. Undefined: include meat broth, yeast extract, blood products etc
Is it easier to grow bacteria on defined or undefined media?
Undefined usually easier, because will typically not know all the growth factors required
What is the issue with gathering knowledge about bacteria from culturing as we have done so far?
Many important species of bacteria cannot be grown on culture
Define classification
Process of arranging organisms into named groups
Define nomenclature
Process of naming genera, species etc
What are the rules for nomenclature?
First word = genus, second word = species, always ITALIC/underlined
Define species in bacteria
Group of similar strains
What is the higher level of classification?
Domain- >Phylum-> Class-> Order-> Family-> Genus-> Species
What is the lower level of classification?
Strains, giving numbers ans stuff e.g. E. Coli O157:H7
Who discovered E. Coli?
Theodor Escherich
What are the two approaches for defining organisms?
Classical approach (size, shape etc), Molecular Taxonomy (DNA/RNA sequences)
In molecular taxonomy, what defines a species?
more than 70% DNA sequence similarity = same species
What are the 7 categories of tests used to characterise a bacterial colony?
Morphology, Physiology, Biochemistry, Serology, Bacteriophage, Pathogenicity, Chemistry/macromolecular analysis
What are the 4 things you look for in morphology?
Shape, colour, size, texture
What is form, elevation and margin?
Used to describe the shape/height/edge of colonies
What are the 4 typical classes of cell shape?
Cocci (spherical), Rods, Vibrio (comma-shaped), Spirillum (spiral shaped)
What are examples for the 4 cell shapes?
C-Micrococcus Luteus, R-Bacillus Cereus, V-Vibrio Alginolyticus, S-Rhodospirillum sp.
Give an example for each 1 dimensional/2D and 3D cell arrangements in colonies
1D-streptococci, 2D-staphylococci, 3D-Sarcina
What are the two methods of fixation?
Heat (gentle heating), Chemical (penetrates cell, reacts->inactive/insoluble)
What are the benefits of chemical fixation?
Preserves fine cell structure
What are 2 important features of dyes?
Contain chromophore groups (give colour), bind to cell components
What are the 2 type of ionisable dye (and examples of each)?
Acidic - rose bengal, acid fuchsin. Basic - methylene blue, crystal violet, malachite green
What may affect the efficacy of a dye?
pH
What type of stains were first undertaken by Koch in 1877?
Stained dried bacterial smears with methyl violet
Who developed Acid-fast staining?
Paul Ehrlich
What leads to staining from acid-fast technique?
High lipid content in cell walls of bacteria
Outline the method for Acid-Fast staining
- Smear w/ Hot carbol fuchsin, 2. Wash with water, 3. 10min 20% H2SO4, 4. Wash again 5. Counterstain w/ methylene blue
Give an example of an acid-fast bacteria?
Mycobacteria
Who invented the Gram stain, what does it differentiate?
Christian Gram in 1884, differentiates based on cell wall structure
Outline the method for Gram staining
- Heat-fixed smear + Crystal violet (basic), 2. Iodine/KI added, forms [CVI] in cells, 3. Wash with solvent (95% ethanol), 4. Stop with water, 5. Counter-stain w/ carbol fuchsin
What colour would a gram positive cell be using a gram stain?
Dark purple (it would appear pink if gram negative)
What is the common name for Saccharomyces cerevisiae?
Bakers/Budding yeast
What is the equation for fermentation (including ATP)?
C6H12O6 —> 2CO2 + 2C2H5OH + 2ATP
How does yeast respire when it runs out of glucose?
Use ethanol produced to grow aerobically
What are the pros and cons of ethanol respiration compared with fermentation in yeast?
Respiration produces more ATP (more efficient) but is slower than fermentation
When and where did the first alcoholic beverage arise?
6000BC, Sumeria, China
How long can yeast spores survive?
25million years
Wine and Sake yeast have distinct phylogenetic groups, what does this suggest?
Two separate domestication events
Who discovered the first microscope and at what time?
Antonie van Leeuwenhoek in 1860, observed yeast in fermenting beer
Who first showed that yeast was essential for fermentation?
Theodor Schwann
What did Justus von Liebig believe?
Wrongly believed that fermentation was a chemical reaction - yeast = non-living catalyst
What did Louis Pasteur show?
Heating brewing mixture killed yeast, fermentation was anaerobic
What did Buchner show?
Living yeast cells produce enzymes, activate fermentation w/out cells
Who was the inventor of Carlsberg lager?
Jacob Jacobsen in 1845, beginning of biotechnology
Who learned to culture yeast from single cells?
Emil Christian Hansen, also identified lager yeast
What is lager yeast a cross between?
S. cerevisiae x S. bayanus
What is Øjvind Winge commonly known as?
The father of genetics and director of carlsberg labs
What did the father of genetics discover?
That yeast had sex and useful for model organism
Why is yeast a model organism?
Genetically simple, quick growing, easy to manipulate, homologous to human genes - act as host for mammalian genes
What is the life cycle of S. cerevisiae with rich media?
a and α haploid cells mate to make a/α diploid, budding, process repeats
What changes undergo in the life cycle of S. cerevisiae when not rich media?
after mating, sporulation occurs, an ascus with 4 spores forms, germination occurs when rich media reintroduced
How is the mating type of S. cerevisiae controlled?
Genes at MAT locus (MATa/MATα) control expression using pheromones and receptors
What is a shmoo?
In S. cerevisiae, occurs when haploid yeast cells grow toward each other and ‘kiss’
What is auxotrophy?
A mutation leading to the inability of an organism to synthesise a compound necessary for it’s growth
What is prototrophy?
The ability to synthesise all compounds necessary for growth
What is the process for detecting auxotrophic mutations?
Haploid cells, mutagenise (increase auxotrophs), grow on rich medium, replica plate to minimal medium, some colonies wont grow, add each nutrient back separately to see which it needs
What happens if you cross a lysine auxotroph with a wild-type prototroph?
Wild-type is dominant, so complements mutant and cell can grow without lysine
What happens if you cross a lysine auxotroph with a methionine auxotroph?
Both mutant genes complemented, so cells can survive without lysine/methionine
What is the procedure of tetrad analysis?
cross 2 diff. strains (meiosis), separate out 4 haploid spores (tetrad dissection), germinate on rich medium, replica-plate to minimal medium, mendelian segregation 2:2
What occurs in tetrad analysis if genes are not close/linked?
two mutations occur, random segregation = all new combinations of mutations in spores, random/independant segregation, no genetic linkage
What occurs in tetrad analysis if genes are close/linked?
crossovers will rarely (unlikely) occur, spore genotypes same as parental - no new combinations
What is an example of two auxotrophic loci which are close together?
TYR1 and LYS2 - crossovers between these are rare —> genetic linkage
What is equal to the frequency of recombination between mutations?
Equal to separation on chromosome
What can be built using many tetrad analyses?
A linkage map of auxotrophic mutations
What is a shuttle vector?
A plasmid constructed so it can propagate/grow in 2 different species, useful because manipulated in simple organism—>more complicated
What is one species that shuttle vectors can typically propagate in?
E. coli
What is the method for cloning a specific single gene?
Cut up wild type genomic DNA (yeast), insert pieces into plasmid, test each plasmid for complementing ability of auxotrophic lys2 mutant
What is a restriction endonuclease?
enzymes, cut DNA molecule at specific sequence
Where does EcoR1 cut between?
G/AATTC
How are sticky ends attached together?
Using DNA ligase
How do we create a genomic library?
mix and ligate wild type restriction fragments with shuttle vectors, transform into E. coli and amplify
How do you screen a genomic library?
transform lys2 with genomic library, complement mutant allows growth in absence of lysine
What drug does the yeast marker gene KanMX4 give resistance to?
G418
What is Artimisinin?
Malaria drug, potent but expensive, from Artemisia plant
Define synthetic biology
engineering/designing organisms with new features
What is Candida albicans?
Thrush, present in 80% of gut flora, switches to invasive filamentous form during infection
What form is Candida albicans in when it’s infectious?
Multicellular filamentous form
What is Schizosaccharomyces pombe (fission yeast) used for?
easy to handle for genetic stuff
What’s pombase?
Scientific resource for fission yeast
What does CESR stand for?
Core environmental stress response
What is the relationship between rapid growth and stress protection?
Antagonistic, stress protection inhibits growth (CESR)
What was the first eukaryotic cell to be completely sequenced?
Saccharomyces cerevisiae, took 600 people in many labs and many years
What have been the advances in sequencing?
can sequence all RNAs, quicker, genetic variation within species, can sequence even non-coding RNAs
What is the transcriptome?
Set of all RNA molecules, including tRNA, mRNA, rRNA etc
What 4 things after gene-environment interactions then lead to the phenotype?
Transcriptome, mRNA, non-coding RNA, Proteome
What is the Proteome?
entire set of proteins expressed by the genome
What are the similarities/differences between the capsule and slime layer present on the outside of bacteria?
S: made of polysaccharides, D: capsule harder to remove and more organised than slime layer
What is polyhydroxybutyrate present in?
Inclusion bodies
What is the role of inclusion bodies?
Storage of metabolites
Name 7 things present in a bacterial cell that you’d observe under an electron/light microscope
Spore, Polyhydroxybutyrate, Polyphosphate, Flagellum, Pilus, Slime, Capsule
What is the role of a spore present inside a bacterial cell?
Used for surviving extreme conditions (dryness, heat, pH etc)
What is the role of polyphosphate inside the cell?
Energy storage (like ATP)
What is the role of the pilus?
Hairlike appendage, used in bacterial conjugation
What is the function of the slime layer?
Protect from environmental stressors -> antibiotics, desiccation
What is the name for bacteria which can fix Nitrogen?
Diazotrophs
What is an example of a bacterial species which isn’t sensitive to UV light (unlike many)?
Deinococcus species (also some species found in the stratosphere)
What is the optimum temperature for psychrophiles, mesophiles, thermophiles, hyperthermophiles?
P: 4deg. M: 39deg. T: 60deg. H: 88-106deg.
What is an example of a species which is a psychrophile?
Polaromonas vacuolata
What is an example of a species which is a mesophile?
Escherichia coli
What is an example of a species which is a thermophile?
Bacillus stearothermophilus
What is an example of a species which is a hyperthermophile?
Thermococcus celer, Pyrolobus fumarii
At what temperatures does membrane gelling occur, and what does this lead to?
Low temperatures, slows transport processes, prevents growth
At what temperatures does protein denaturation occur, and what does this lead to?
Collapse of cytoplasmic membrane, thermal lysis
What is the name for an organism with salt tolerance?
Halophile
What salt concentration (%) can most marine organisms survive in?
3.5%
What is the salt concentration in Lake Tyrrell?
33% NaCl, 330g/L
What is the name for bacteria able to survive low and high pH & examples?
Acidophiles (Helicobacter pylori- pH 2) and Alkaliphiles (Bacillus- pH 12)
What is the definition of a microaerophile?
Damaged by normal atmospheric levels of oxygen, but grow at low oxygen levels
What is the definition of an aerotolerant anaerobe?
Can grow with O2 present, but don’t need it
What are obligate aerobes/anaerobes?
need O2/cannot grow with O2 - respectively
What is a facultative aerobe?
Can grow without O2 but will use it if present
What experiment would we use to distinguish aerobes and anaerobes?
Fill test tube with soft nutrient agar, O2 would only penetrate a short distance into agar
What rate does pressure increase at with ocean depth?
every 10m increases by 1Atm
What is a barophile?
Bacteria which grows best at high pressures
Which two -philes are deep-sea bacteria?
Barophiles and Psychrophiles
What are three types of chemical inhibitor?
Respiratory inhibitors, Chaotropic agents, Antibiotics
Give an example of a respiratory inhibitor and a bacteria which is resistant to it
Sodium Azide (NaN3), gram +ve bacteria resistant such as Enterococcus faecalis
What is a chaotropic agent?
Disrupts hydrogen bonding network in water, reduced hydrophobic effect, and reduces stability of native state molecules
Give an example of a chaotropic agent and a bacteria which is resistant to it
Phenol, Pseudomonas
Why is Mycoplasma pneumoniae resistant to penicillin?
Lacks a cell wall for penicillin to damage and penetrate
What 3 methods are used for testing antibiotic sensitivity?
Bacterial isolates using MICs, antibiotic impregnated discs, graduated strips
What are the two pathways used when investigating sugar metabolism?
Fermentation, Oxidation
What differentiates species in fermentation?
The type of waste products released
What is the method of the test for products of fermentation?
add liquid media, sugar and pH indicator and a Durham tube into a test tube, wait 24 hours
What is a Durham tube?
Used to test for gaseous products of microorganisms, simply a smaller test tube inserted into a larger test tube
What is the test used for seeing whether the microorganism undergoes oxidation or fermentation, what are the results?
Add soft agar, glucose and pH indicator into test tube, if growth only near top then oxidative (blue), if throughout whole tube then fermentation (red)
What is an example of a bacteria which only undergoes oxidation, and one which undergoes fermentation ?
O: Pseudomonas. F: Escherichia coli
What are the steps and results of the catalase test?
add H2O2 to cell colony on glass slide, bubbles=catalase present
What is an example of a bacteria which contains catalase and one which doesn’t?
Catalase: Staphylococci. No catalase: Streptococci
What is the rapid urease test (CLO test)?
Tests for presence of urease which catalyses Urea—> NH3, leads to pH rising —> pH indicator and Urea on test strip, test strip would change colour from yellow->red if urease present
What bacteria is tested for using the urease test?
Helicobacter pylori, gastritis
What is serology?
Detection of bacterial antigens using specific antibodies
How are tests for serology undertaken?
Inject antigen into animal, harvest antibodies, test in vitro for recognition of cell surface antigens - can use microarrays, antibody usually labelled with radioactive dye
What is bacteriophage typing and what is it used for?
(some) bacteriophage can only infect specific strains of bacteria, used to identify different strains of a virus
What is a bacteriophage?
A virus that infects and replicates within an organism
What is pathogenicity?
Using symptoms of a disease to identify identity of pathogen
What are the telltale symptoms of Corynebacterium diphtheriae?
Formation of a pseudomembrane at the back of the throat
What are the telltale symptoms of Mycobacterium leprae (leprosy)?
Loss of fingers and toes due to loss of feeling
What are the telltale symptoms of Yersinia pestis?
buboes, skin darkening
What are the 4 methods used in DNA analysis?
Genome sequencing, DNA hybridisation, PCR, Labelled nucleic acid probes
What % hybridisation between two samples suggests they are the same species?
> 70%
What is the advantage of DNA-based tests?
Don’t need to culture bacteria first, so tests are much faster
Define Metagenomics
mass sequence analysis of microbial populations without isolation or culturing - Dr. Craig Venter
What two processes accompany cell division in bacteria?
Budding and Binary fission
What is binary fission?
When a bacterial cell divides into 2 parts (multiple fission produces many parts)
How many planes can rods and cocci divide in?
Rod: only 1 plane. Cocci: 1, 2 or 3 planes
What is the fastest time a bacteria can replicate and what is the bacteria?
10m, Vibrio natriegens - marine bacterium found in salt marsh mud
What would the mass of bacteria after dividing exponentially from one bacteria for 48 hours?
2^144 x 10^-13g = 2 x 10^27kg = 300x the mass of the earth
What is the process for batch culture?
inoculate growth medium w/ small amount of culture, incubate with shaking
What are the 4 cell phases of growth?
Lag, log/exponential, stationary, death
In log phase cell population doubles at particular time intervals
HELL YEH
Why does growth slow in stationary phase?
nutrients/oxygen exhausted, waste products accumulate, cell density
What is tgen?
mean generation time/average doubling time of a population, found by plotting logN (y) against time, finding time when population doubles
What is an example of a bacteria with a tgen of weeks?
Mycobacterium leprae
What is the tgen time of E. coli in rich media?
~30minutes
What are the 3 different ways to count large amounts of cells?
look at very small volume (extrapolate), carry out large dilution, don’t count the cells
What is a haemocytometer used for?
Counting cells
What are disadvantages of using a counting chamber to count cells?
Tedious, counts dead cells to
How do you work out the concentration of original culture in a serial dilution?
[dilution factor x no. of colonies]/volume plated
When carrying out a serial dilution, you should use a plate with ~how many colonies on it?
Several hundred colonies
What are the unites typically used in the serial dilution method?
Colony forming units
Describe the spread-plate method
Pipette small amount of solution onto plate, spread, count colony forming units, divide cfu by volume pipetted
Why is the spread-plate/serial dilution method more effective than using a counting chamber?
Counts only live cells
What method is used for counting cells that does not require actually counting?
Optical density, using a spectrophotometer
What are the pros/cons of using a spectrophotometer to estimate cell counts?
A: Very quick and easy. D: only works on dense cultures
Light from what wavelength is used in a spectrophotometer to estimate cell numbers?
540nm-650nm
What are the units used in spectrophotometer cell counting?
Klett units
What is a coulter counter and how does it work?
automated counter of individual cells, works by forcing cell suspension through small hole surrounded by electrodes, whenever a cell passes through hole, the current drops
What are the issues with the coulter counter?
Is inaccurate for smaller bacterial cells, debris/filaments can affect it, can’t distinguish live/dead cells
What other ways are used to count cell numbers (3)?
Biomass (dry and weigh), Most probable number (dilutions, statistical tables), Electrical impedance (current, solution, ionic metabolites decrease current)
What equipment is used in continuous culture?
A chemostat, big vat
What is kept constant in a continuous culture?
everything lol (conditions)
What are the 3 levels of microbe removal in vitro and what are their definitions?
Decontamination (physical removal of most contaminating microbes), Disinfection (killing most contaminating microbes), Sterilisation (killing all microorganisms)
What are the different methods of removing microbes in vitro (5)?
Heating (Autoclave, oven, pasteurisation), Chilling (fridge, freeze), Radiation (UV/gamma), Filtration (depth, membrane), Chemical (bacteriostatic, bacteriocidal, bacteriolytic)/Antimicrobial agents
What is the Decimal reduction time (D)?
Time for population of microbes to be reduced to 10% of original value at a certain temperature, higher temp = shorter D
What temperature should be used to ensure sterility?
100deg. sustained
What conditions are used in an autoclave?
121deg., 15Psi, 15mins
What is the benefit of moist heat?
Transfers energy more efficiently, denatures enzymes, nucleic acids, membranes
How does dry heat kill bacteria?
By oxidation
What are the benefits of pasteurisation?
Moderate heating reduces microbial load without excessive product damage
Which type of bacteria are not affected by refrigerating at 4deg.?
Psychrophilic bacteria
What temperature is a deep freeze undertaken at?
-18deg.
Why can no bacteria grow at the temperatures of deep freeze?
Bacteria require liquid water to grow
What wavelength range is UV light?
220nm-300nm
How does radiation kill microbes?
by damaging DNA
What limitations are there to UV light sterilisation, and so, what applications is it used for?
UV light cannot pass through glass/opaque materials, used for sterilising water and work surfaces
What radiation source is used for gamma sterilisation?
Cobalt 60, Caesium 137
What does gamma radiation produce to kill microbes?
short wavelength gamma radiation produces lethal free radicals
What are gamma rays used to sterilise?
Heat sensitive stuff -pass through everything, and food
What is the difference between depth filters and membrane filters?
Depth filters are fibrous mats, whereas membrane filters are porous membranes
What is the difference in usage of depth filters and membrane filters?
D: used as pre-filter for gases/liquids and in clean rooms. M: Sterilisation of heat sensitive liquids in lab
Is a HEPA filter a membrane or depth filter?
Depth filter - High efficiency partical air
What is the typical pore size of a membrane filter compared to the width of a bacterial cell?
Membrane = 0.22micrometers-0.45micrometers. Cell = 1micrometer
What are the 3 different chemical antimicrobial agents and what are their different effects?
Bacteriostatic (stops growth but doesn’t kill), Bacteriocidal (irreversibly inhibits growth, kills), Bacteriolytic (kills by lysis)
What does MIC stand for?
Minimum inhibitory concentration
What are some common in vitro antimicrobial agents?
Sterilants (formaldehyde, sodium chlorite), Disinfectants (bleach), Antiseptics (ethanol, iodine)
What are chemotherapeutic agents?
Synthetic compounds found by trial and error
What concept did Paul Erlich develop, and what drug/diease did it lead to?
Concept of selective toxicity (magic bullet), invented Salvarsan as treatment for syphilis
What is a growth factor?
Substance taken up from medium because microorganism uses factor in essential metabolic process
What is a growth factor analog?
Modified form of growth factors which competitively inhibits metabolic process
How does Sulfanilamide treat a certain disease?
Used for streptococcal infections, sulfanilamide is a growth factor analog of p-Aminobenzoic acid which is necessary for the production of Folic acid by bacteria
Why doe sulfanilamide not kill human cells?
Animals do not synthesise Folic acid themselves as it is gathered from their diet
What is commonly added to nucleic/amino acids to make them toxic?
Halides such as Fluorine and Bromine
What are quinolones?
Group of synthetic antimicrobials that inhibit DNA gyrase and topoisomerase IV
What are the roles of DNA gyrase and topoisomerase IV in bacteria?
Responsible for supercoiling DNA
What is an example of a quinolone?
Ciprofloxacin
What are quinolone used to treat (2)?
UTIs and Anthrax infections
How does the targeting of enzymes by quinolone’s vary between gram positive and negative bacteria?
G+: attack topoisomerase IV. G-: attack DNA gyrase
Why are antibiotics produced by microbes?
In order to eliminate competitors
What was the first commercially produced antibiotic?
Penicillin by Penicillium notatum, Fleming 1929
Roughly what concentrations are antibiotics affective at in cells?
Very low, 1-2micrograms per ml
What everyday object is the turgor pressure of a cell equal to?
A car tire
What is peptidoglycan made from and how does it achieve it’s strength?
sheet polymer of sugar derivatives, achieves strength through cross-linking
What is the structure of peptidoglycan and what is the name of the sugar derivatives it uses?
NAG (N-acetlyglucosamine) and NAM (N-acetylmuramic acid) are bound to each other forming heterodimers then long chains, peptide cross links between M’s of adjacent fibres
Which has a thicker peptidoglycan layer, gram positive or gram negative?
Gram positive (positive people are always the thick ones)
In a gram positive cell, what percentage of the total cell wall is peptidoglycan?
90%
Other than peptidoglycan, what else makes up the bacterial cell wall in a gram positive cell?
wall-associated proteins, Teichoic acids and lipo-teichoic acids
What is the difference between Teichoic acids and Lipoteichoic acids in a gram positive cell?
Lipoteichoic acids run through whole of cell wall and into cytoplasmic membrane
What makes up the cell wall of a gram negative cell?
Outer membrane = Lipopolysaccharides (LPS), Proteins, Porins, Lipid A, Lipoproteins, peptidoglycan layer
What two layers make up the cell wall in a gram negative cell?
The outer membrane and the periplasm
What % of a gram negative cell wall is peptidoglycan?
10%
What is the difference between Teichoic acids and Lipolysaccharides and which type of cell are each present in?
Teichoic acids: polyalcohols embedded in cell wall of gram positive cells. Lipopolysaccharides: lipids with attached sugars bound to outer membrane of gram negative cells
What chemical attacks the cell wall of bacterial cells and what is it commonly found in?
Lysozyme, tears, nasal mucus, breast milk, egg white
How does lysozyme break down the peptidoglycan cell wall?
Cuts between NAG and NAM breaking the glycol chain
How does breakdown of the peptidoglycan cell wall affect the cell?
Causes the cell to swell up and burst - antibacterial
What is the function of lysozyme in the body?
Used as defence against bacteria
How does penicillin cause breakdown of the cell wall?
Inhibits transpeptidases which cross link the peptidoglycan, weakens cell wall
What are the function of transpeptidases in the cell wall?
Cross link the peptidoglycan
What is the functional ring in penicillin?
beta-lactam ring
What are 2 examples of bacteria which are particularly sensitive to penicillin?
Streptococcus and Staphylococcus because they are gram positive
How do bacteria inactivate antibiotics?
Addition of side groups or cleavage of ring structures
How do bacteria inactivate penicillin?
Break beta-lactam ring with beta-lactamase
What is the name of a new approach to antibiotics?
Bacteriophage lysins = Protein antibiotics
What enzyme is produced by the phage which causes it to be effective and how does this enzyme work?
Lysin, small single polypeptide cleaves peptidoglycan cell wall
How large is lysin?
30-40kDa single polypeptide
Why are lysins more effective than traditional antibiotics?
Have many different sites of attack to breakdown cell wall, can be used from outside or inside the cell wall
How do lysins vary in their specificity compared to antibiotics?
Lysins are much more specific
What are the two domains of Cpl-1 lysin, and what bacteria is it used for?
Muramidase domain, phosphocholine binding domain, specific for Streptococcus pneumoniae
How do you alter the specificity of lysins?
Create recombinant lysins with different domains
How long would it take 10ng of lysins to kill 10^7 cells?
Less than 5 seconds
What has the smallest non-symbiotic bacterial genome and what size is it?
Mycoplasma genitalium - 0.58Mb
What is the size of the Escherichia coli genome in base pairs?
4.6Mb —> fairly average
What is the comparison between sizes of an E. coli chromosome and cell?
Chromosome: 1.4mm long Cell: 4micrometers long —> CHROMOSOME MUCH BIGGER
How many copies of its chromosome does Escherichia coli have?
1 copy, unless it’s just about to divide
How many copies of chromosomes do cyanobacteria typically have?
10
How is bacterial DNA arranged in the nucleoid?
tightly folded and packed into an irregular structure
Is archaeal DNA packaging similar to eukaryotes or prokaryotes?
Eukaryotes, DNA wound around histones
Is there a correspondance between genome size and lifestyle complexity?
yep
Give a brief overview of Streptomyces coelicolor
8.7Mb genome, soil bacterium, complex structure, undergoes sporulation
Give 2 examples of archaea with small/large genomes
Prochlorococcus marinus (1.67Mb), Anabaena cylindrica (6.37Mb)
What is the most abundant oceanic heterotrophic bacterium?
Pelagibacter ubique, so small because it lives in nutrient poor habitat
Why do bacteria streamline their genome (2)?
DNA is expensive in terms of energy and nutrients, time taken to replicate genome is proportional to genome size
Give 3 relevant words about bacterial replication
Origin of replication, replication forks, bidirectional
What enzyme is used to replicate the chromosome?
DNA polymerase, assemble nucleotides
In bacteria, the size of a chromosome is directly proportional to the replication time, why is this not the case in eukaryotes?
Replication in eukaryotes can proceed at multiple sites simultaneously
What are the 3 main steps of bacterial cell division ?
DNA replication, chromosome partitioning, cell division
What are ORFs?
part of a reading frame that has the potential to code for a protein or a peptide
How many different ways can a DNA sequence be read (how many different reading frames)?
6 ways (3 reading frames on each strand, 2 strands)
How many codons code for amino acids, and how many code for stop codons?
61 different codons for AA (20 AA), 3 stop codons
What is the base ordering for a start codon?
ATG/GTG
There is a 1 in 21 chance of a codon being a stop codon, so ORFs which are larger than 40 are likely to code for a gene
Just sayin
How doe prokaryotes vary from eukaryotes in their distribution of genes on a chromosome?
Prokaryotes have a much denser clustering of genes than eukaryotes due to genome streamlining
A gene is more than just an ORF
What are the 3 codons for stop codons?
TAA/TAG/TGA
What are the other important regions on a gene? label 5’ to 3’ end
Suppressors/activators, Start of transcription, 5’ untranslated region (UTR), Shine-Dalgarno sequence (ribosome binding site), Start of translation (ATG/GTG), ORF/coding region, stop codon (TAA/TAG/TGA), 3’ untranslated region, Transcription terminator region
What synthesises RNA?
RNA polymerase
How doe the transcription termination sequence stop RNA polymerase?
inverted repeat sequence causes stalling of RNA polymerase, or Rho protein which binds to RNA
What is the percentage of unknown genes in a prokaryote genome?
40-60%
What is the difference in number of bases per gene in prokaryote and human genomes?
P: 1 gene per 1,000 bases. H: 1 gene per 30,000 bases
There is a set of genes found in all bacteria, how large is this set of genes, and what does this suggest?
~300 genes, suggets these genes are necessary for life (create cell ‘chassis’)
How do horizontal and vertical gene transmission vary?
Horizontal: uptake of genes by another prokaryote (transformation), Vertical: mutation during replication
What are the 2 forms of DNA mutation?
Spontaneous, Induced
What are some forms of spontaneous DNA mutations?
Damage to DNA bases (radiation, chemicals), error in DNA replication (wrong base, slippage, tautomerisation)
What is tautomerisation of bases?
occurs when a base transitions to a different structural isomer, leads to formation of A-C and G-T base pairs
How does nitrous acid cause induced DNA mutations?
converts amino groups to keto acid groups by oxidative deamination, C, A, G —> U, H (hypoxanthine), X (xanthine)
What impact does ethidium bromide have on bases and why is this the case?
Causes addition/deletion of bases, it is an intercalating agent which deforms the DNA strand
How does non-ionising radiation (UV) cause damage to DNA?
Purine/Pyrimidine bases absorb UV radiation —> produces pyrimidine dimers when adjacent C & T become covalently bonded
How does ionising radiation (gamma) cause damage to DNA?
Generates free radicals in cell which damage cell
What are the different types of DNA mutation (base pairs)?
point mutations, insertion/deletion (frameshift)
What noticeable effect could a point mutation outside the ORF cause?
Could change gene expression by mutating the promoter
What effects could a point mutation inside the ORF cause (4)?
change amino acid but not change protein functionality, change protein function, inactivate protein (stop codon), no effect
Define missense/nonsense/silent mutation
Missense: faulty protein. Nonsense: incomplete protein. Silent: normal protein
What would an insertion/deletion mutation lead to in the ORF?
produces frameshift, every codon changed, gene inactivated
What is the cool and hip name for insertion/deletion mutations?
Indels, yuh u got it
What did Francis Crick’s experiments show related to indels?
genetically combining frameshift mutations in same gene restored some protein function if frameshifts added up to 3
What are 4 larger scale mutations?
Deletion, Rearrangement, Duplication, Insertion (from elsewhere on genome)
What is a transposon?
DNA sequence that can change it’s position in the genome
What is a scorable phenotype used for and what are 2 examples of a scorable phenotype?
detecting mutations using change in phenotype, examples include: ability/inability to grow on substrate, resistance/sensitivity to toxin
How would you undertake a screen for lysine auxotrophs in Escherichia coli?
spread cells on lysine plate, make replica plates (velveteen) onto lysine lacking plate, identify auxotrophs as ones which do not grow
How would we designate a lysine auxotroph?
lys-
Define revertant
mutant that reverts to its former genotype or to original phenotype by suppressive/compensative mutation
How do we select for lys- revertants?
plate out cells from lys- culture on plate without lysine - see which colonies grow
What is used to increase the reversion frequency?
Mutagens
Describe the Ames test
Test for mutagenic chemicals: treat an auxotrophic culture with chemical, plate out on minimal medium, more revertants = more mutagenic
When is an increase rate of mutation bad, and when is it useful?
Bad: unchanging environment. Useful: essential for survival when conditions change
What is MNNG?
A potent mutagen
What is the name of genes contained by bacteria which increase mutation rates under certain conditions?
Mutator genes, gives a selective advantage
What is Müllers Ratchet?
As organism replicates, mutations occur, most are harmful mutations (some = death), natural selection does not work fast enough to eliminate all harmful mutations so gradual build up of harmful mutations leading to declining fitness
How do bacteria escape Müllers Ratchet (2)?
DNA repair mechanisms, horizontal gene transfer
What are the 3 known mechanisms for horizontal gene transfer in bacteria?
Transformation (uptake of naked DNA), Transduction (DNA transfer mediated by bacteriophages/viruses), Conjugation (DNA transfer from donor->recipient with cell-cell contact)
What is transformation and how does it occur more readily?
importing of naked DNA into cell, occurs more readily if new cell contains similar sequence (homologous recombination)
What is the method for detecting transformations?
take auxotroph, take wild type - isolate DNA, mix mutants & wild type, select for wild type
What is an example of a bacteria which becomes transformable after pre-treatment with metal ions?
Escherichia coli
During transformation, a piece of wild type DNA is inserted at the correct…
Locus
In bacterial transformation, how is the DNA sequence imported at the correct locus?
single strand taken up, homologous strands separate, base pairing around mutation, crossover occurs (strands broken/rejoined)
What is the most commonly used method to genetically engineer bacteria?
Insert DNA with new gene into plasmid, cause plasmid uptake by bacteria
What is transduction?
DNA transfer mediated by viruses
Give an example of a bacteriophage
Bacteriophage lambda
Describe the lytic cycle
Transduction: Phage DNA infects host DNA, production of new phage (occasionally) with host DNA packaged, host cell lyses, phage containing host DNA infects another cell, DNA transduced by homologous recombination -> cell lysis does not happen
In transduction using bacteriophage, how often do cells become infected?
1 in every 10^7-10^8 cells are transduced
Who showed that conjugation required physical contact between cells?
Lederberg and Tatum in 1946
How did Lederberg and Tatum show that conjugation required cell contact?
U-shaped tube, two strains of bacteria with fine filter separating them, genetic exchange only occurred if bacteria allowed to mix
What is the role of the sex pilus?
Draws the cells together so a cytoplasmic bridge can form
How is bacterial sex not like human rumpy pumpy?
no connection with reproduction, involves transfer of plasmid DNA only (no spermy), low selectivity - do not need to be same species (bestiality)
What type of plasmids are the genes for conjugation carried on?
Conjugative plasmids
What are the conjugation gene present on the E. coli F (fertility) plasmid?
Tn1000 (transposon), IS2, IS3 (insertion sequences), oriT (replication start point)
What is the rolling circle mechanism?
used in conjugation, one plasmid unwinds and passes linearly through the conjugation tube into next cell where it reforms into a circle
What does the R100 plasmid carry resistance to?
Mercury, streptomycin, chloroamphenicol, tetracycline
The spread of which type of plasmid has led to the development of antibiotic resistant bacteria?
R-plasmids
Define episome and give an example
Episome: plasmid capable of integrating into main chromosome, e.g. E. coli F plasmid
What does Hfr stand for?
High frequency of recombination
How does the F plasmid integrate into the chromosome?
via an Insertion sequence, F+ strains where they are integrated that way are called this
What is interrupted mapping and what is it used for?
mate Hfr strand with multiple auxotroph, allow mating for certain time, then FUCKING BLEND?!!!? ur all sick fucks
What proud title does Mycobacterium tuberculosis hold?
The biggest killer of H. sapiens (he beat Chairman Mao - no kiddin)
What is the most abundant primary producer?
Prochlorococcus marinus
What is the largest bacterium?
Thiomargarita namibiensis
What is the most vicious bacterium?
Bdellovibrio bacteriovorus
Is E. coli gram negative or positive?
Gram negative
What is the natural habitat of E. coli?
Animal colons, enterobacterium, can live on range of sugars
Is E. coli an aerobe/anaerobe etc?
Facultative aerobe (aerobic when there is oxygen, but can ferment when little oxygen)
Why is E. coli a good research organism (6)?
easily cultured, rapid growth, mostly harmless, lab strains are typically auxotrophic, genetically understood, easy to genetically manipulate
What are 5 of E. coli’s activities in the colon?
converts food nutrients into biomass, maintains anaerobic conditions (uses O2), limits colonisation by harmful bacteria (probiotic), produces vitamin K, cause disease
What two general methods do bacteria cause disease?
Toxicity (inhibit/kill cells), invasiveness (growth in host tissue)
What bacterial toxin causes Tetanus?
Clostridium tetani
What do pathogenic strains of E. coli contain?
fimbriae (attachment pili - fluffy border), allows colonisation of small intestine
What type of bacteria is Mycobacterium tuberculosis (gram +ve/-ve)?
Gram positive
Who first isolated Mycobacterium tuberculosis?
Robert Koch
What are the symptoms of mycobacterium tuberculosis colonisation?
fever, coughing, bloody sputum due to destruction of lung tissue
How does mycobacterium tuberculosis resist macrophage attack?
Mycobacterium can grow and divide within macrophages after they have been engulfed, and pop goes the weasel
What are some important features of Pseudomonas (5)?
gram negative, highly motile, versatile, opportunistic, soil microbe
What type of bacteria is Prochlorococcus marinus (2)?
Cyanobacteria (unusual pigmentation), photoautotrophic
Although prochlorococcus marinus is the most dominant organism on our planet, why was it not discovered until 1988?
Too small to be trapped by standard water filters (0.4micrometers)
Thiomargarita namibiensis is the largest bacterium, but what organelle makes up most of it’s cell volume?
Vacuole, cytoplasm is only thin line around the edge
What type of bacteria is Thiomargarita namibiensis?
Chemolithotroph (H2S electron donor, N2 electron acceptor)
What is the purpose of the huge vacuole in Thiomargarita namibiensis?
Used to store nitrate, which is only available when storms stir up the sediment
What are some points about Bdellovibrio bacteriovorus (6)?
most vicious, gram negative, curved rod, flagellum (highly motile), small, widespread in soil/water
Why is Bdellovibrio bacteriovorus such a vicious predator? What makes it griminal?
Drills through periplasm, eats bacteria from inside, and then reproduces inside the carcass, also bears resemblance to Nigel Farrage
Why are bacteria useful industrial catalysts (4)?
cheap, self-assembling, operate at normal temp/pressure, specific processes
What are 8 examples of where bacteria are used as industrial catalysts?
Biodegradation, mineral extraction, agriculture, chemical industry, pharmaceutical industry, biotechnology, food industry, vaccines
What type of bacterium are used in sewage treatment, and what do they form?
Aerobic, slime-forming bacterium, grow in flocs and biofilms, convert organic matter into minerals
What is ammonia converted to in sewage treatment plants?
Nitrate/Nitrites
It is not a clan of bacteria, nor a gang of bacteria, it is a….. of bacteria
floc or biofilm
What is the term for extracting minerals using bacteria from low grade ores?
Bioleaching
Which bacteria is used for copper extraction, and what does it convert the copper sulphide ore into?
Thiobacillus thiooxidans, Converts Copper sulphide to copper sulphate (soluble)
Why is the conversion of copper sulphide to copper sulphate useful for copper extraction?
Copper sulphate is soluble, therefore easy to extract
Where is an example of a bioleaching copper plant?
Bingham Canyon, Utah, North America, Earth, The Milky Way
What bacteria is responsible for nitrogen fixation?
Rhizobium leguminosarum, live on root nodules of legumes, and do their thang
What do the plants give the Rhizobium leguminosarum in return for their fixing of nitrogen?
They give fixed carbon via photosynthesis (and a little bit of love and affection)
What is a complex enzyme present in prokaryotes (like Rhizobium) which scientists would very much like to help our crops?
Nitrogenases, reduces reliance on nitrogen fertilisers
What is a ruminant and give examples
Mammals that can obtain nutrients from plant-based food by fermenting it in their rumen e.g COW COW COW COW COW GOAT
How is it possible for cows to break down cellulose?
microbes! Microbial ecosystem can digest cellulose and other recalcitrant carbohydrates
What is silage?
Fermented cereal crops/grasses etc, used as biofuel feedstock (just so you’re aware, when you eat a burger, you’re eating a dead, minced up, fermented shit muncher)
How is silage made?
Made by adding Lactic acid bacteria (Lactobacillus planterum) to cereal crops to partially anaerobically digest them
What is an example of a biopesticide specifically toxic to insect?
Bacillus thuringiensis
How does Bacillus thuringiensis kill insects, and why is it specific to only insects?
Toxins produced during sporulation which require an alkaline gut for activation —> only insects have an alkaline gut
What is the commercial name of the Bacillus thuringiensis spores?
Thuricide
What is another, more controversial, way of killing pests using Bacillus thuringiensis?
Genetically engineering gene to produce toxin into the crop, so when pests eat it, they die, this is called Bt maize
What material can be produced by bacteria in industrial bacteriology?
Xanthan Gums (Xanthomonas campestris), Polyhydroxyalkanoates (biodegradable polymer),
How are PHAs broken down?
UV light breaks down polyhydroxyalkalnoates
What can bacteria be used to grow in the health food and pharmaceutical industry?
Antibiotics (streptomyces, bacillus), essential vitamins (B12), Amino Acids (MSG, aspartame)
What are the symptoms of Vitamin B12 deficiency and where do most people find their source of it?
Anaemia, fatigue, depression, found in animal products (vegans r fucked)
What is aspartame made from?
L-phenylalanine and L-aspartic acid
How are bacteria utilised in the biotechnology industry?
Used for production of commercially valuable proteins, e.g HGH, Insulin
What is pruteen?
A single cell bacteria which could be used as food, uses ethanol and ammonia to grow
What are the ways bacteria can be used in disease prevention?
Vaccines, research into biological warfare
What does the name ‘protozoa’ mean?
First animals
What are some important features of protozoa (6)?
Single cell eukaryotes, no rigid cell wall, generally motile, inhabit wet environments, heterotrophs, sometimes parasitic
What is the difference between protozoa and algae?
Algae contain a plastid (such as a chloroplast-phototrophic)
What is the collective term for protozoa and algae?
Protists
What does polyphyletic mean?
phenotypes which appear the same but do not have common ancestors
Are protozoa and algae polyphyletic?
Yes, they are not from the same taxonomic group
Which protozoa causes malaria?
Plasmodium falciparum or Plasmodium vivax
What disease to Trypanosomes cause and what is it’s vector?
African sleeping sickness, tsetse fly
What are 4 diseases caused by protozoa?
Malaria, African sleeping sickness, Dum dum fever, Amoebic dysentery
What protozoa is the cause of Dumdum fever?
Dumdum fever is otherwise known as Leishmaniasis and is caused by Leishmania
What causes amoebic dysentery?
Entamoeba
What protozoa was the cause of potato blight?
Phytophthora infestans
What is the genus name of a protozoa which affects many plant species?
Phytophthora
What infects cocoa pods?
Phytophthora palmivora
What cause famous Red tides?
algal blooms of Dinoflagellates —> means whirling whip in latin
What is Saul Purton’s favourite protist, also responsible for the white cliffs of dover?
Emiliania huxleyi
What do Emiliania huxleyi convert CO2 into?
Glucose and Calcium carbonate (hence white cliffs)
What is Saul Purton’s incredibly witty and funny pun about Diatoms?
Eukaryotes in Glass houses (In other news, Saul Purton is now considered a pathogen because his jokes are toxic)
What is the key ingredient of dynamite, and who was it’s inventor?
Diatomaceous earth, Alfred Nobel
Eukaryotes are believed to have evolved from________via a proces of________, ________ and __________?
Archaea, internal membrane formation, cell enlargement, serial endosymbiosis
What is the definition of serial endosymbiosis?
several key organelles of eukaryotes originated as symbiosis between separate single celled organisms
How were organelles formed which were not part of serial endosymbiosis?
Invagination of the outer cell membrane to create membrane surrounded sacs, e.g. Endoplasmic reticulum
What are 2 examples of internal membrane systems within modern bacteria (name, system)?
Gemmata obscuriglobus - nuclear envelope. Cyanobacteria - thylakoid membranes
Which came first, the alpha-proteobacterium or the cyanobacterium?
alpha-proteobacterium (mitochondria)
What were the 4 stages of eukaryote formation?
Archaea —> proto-eukaryote —> eukaryote —> photosynthetic eukaryote
What are the 4 major groups of protozoa?
Alveolates, Euglenoids, Oomycetes, Sarcodina
Why are the Alveolates (protozoa) so-called?
cells possess alveoli —> fluid-filled membrane sacs under cell membrane
What are alveoli?
Fluid-filled membrane sacs under cell membrane
What are the 3 main phyla of Alveolates (w/ examples)?
Ciliates (paramecium), Sporozoans (plasmodium, cryptosporium), Dinoflagellates
What are some important features of ciliates (6)?
most complex single celled organism, found in water everywhere, cell surface covered with cilia, feed on bacteria/algae/other ciliates, can harbour symbiotic algae, can form cysts to survive drying
What is the most complex single celled type of organism?
Ciliates
How does paramecium (ciliate) reproduce?
asexually or sexually by conjugation
Give an example of 3 ciliates
Vorticella, Stentor, Paramecium
What is the defining feature of the sporozoans?
They are a haploid parasitic protozoa with growth stage inside eukaryotic cell
What are the apicomplexans?
Protozoa —> Alveolates —> Sporozoans —> Apicomplexans, distinctive structure at apical end of sporozoite which is involved in host cell invasion
What are 3 examples of apicomplexans?
Plasmodium, toxoplasma, eimeria
What are the euglenoids (3)?
flagellated protozoa—> Euglena, Trypanosomes, Leishmania
What is bleaching in relation to Euglena?
When the chloroplast in an euglena is easily lost
What defines a trypanosome (2)?
insect host, contain a kinetoplast
What is a kinetoplast and what is it present in?
Specialised DNA-containing structure in mitochondria of Trypanosomes
What is the vector, disease and symptoms of the Trypanosome brucei euglenoid?
Tsetse fly, sleeping sickness, fever, joint pains, torpor, coma, death
What are some facts about the Oomycetes (4)?
water moulds, filamentous protozoa, free-living/parasitic, fungal-like/rust/mildew appearance
Oomycetes were originally considered to be funghi due to their appearance, what group are they now known to be related to?
Chromista (golden algae)
What are 3 species of Oomycete and their diseases/symptoms?
Phytophthora infestans - potato blight. Plasmopara viticola - grape mildew. Saprolegnia - fish scales, lesions
What is the largest phylum of protozoa?
Sarcodina/Rhizopoda
What are some points about Sarcodina (4)?
Amoeba, uses pseudopodia, free-living mostly
What process drives the movement of the pseudopod?
Actin assembly
What is a clever little amoeba, and why is it clever?
Dictyostelium discoideum, usually feeds on bacteria in soil, when food scarce it becomes a slug, then differentiates into fruiting structure and releases spores
What is the translation for histo-lytica?
Tissue-destroyer
What relationship does Entamoeba have with the human race?
It’s a mother fucking pathogen, kills 100,000 each year
What are the two life cycle stages of Entamoeba histolytica?
Motile amoeba (trophozite) and cyst
How do the Entamoeba cysts survive conditions in our stomach and pass through into our bowel?
cysts are resistant to stomach acid, can pass through bowel
What disease does Entamoeba histolytic cause?
Amoebic dysentery EW
What is the latin name for the sarcodina which causes gingivitis?
Entamoeba gingivalis
How did algae evolve?
Replication of endosymbiont, replication of host
Which genes were lost by the symbionts due to selective pressures?
Genes for: flagella, cell wall, scavenging micronutrients, copies of host metabolic pathways
Many genes transferred from cyanobacterium to host nucleus
yep
How many genes does a modern chloroplast contain? How much lower is this compared to cyanobacteria genome?
100-200 genes, 95% lower than cyanobacterium
What 3 lineages have been as a result of primary endosymbiosis of cyanobacterium?
Chlorophyta (green), Rhodophyta (red) and Glaucocystophyta
Which pigments have evolved in the red/glauco lineages of algae?
Phycobilins + chlorophyll a
Which pigments have evolved in the green lineages of algae?
Chlorophyll B + chlorophyll a
What gave rise to all land plants?
The chlorophyta
What is volvox?
A genus of chlorophytes, type of green algae
How many cell types does volvox have (and what are they)?
2 cell types: small flagellated somatic cells, large germ line cells within sphere matrix
What is important about the glaucocystophytes (glaucophytes)?
Chloroplast in these glaucocystophytes has retained it’s peptidoglycan cell wall showing it’s endosymbiotic past
In what way are the glaucocystophytes different to chlorophytes and rhodophytes?
Glaucocystophytes have a peptidoglycan cell wall surrounding their chloroplast, chlorophytes and rhodophytes do not have a cell wall
What is secondary endosymbiosis?
ENSLAVING A WHOLE ALGAE (it’s like the apartheid, but diff. colours)
What is a nucleomorph?
Left over eukaryotic nuclei found between inner and outer membranes of some plastids
