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173 Cards in this Set
- Front
- Back
Nuclear pore & nucleolus in Prokaryote? |
Absent |
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Cell wall of a Prokaryote? |
Peptidoglycan |
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Chromosome in Prokaryote? |
Single & circular |
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Ribosomes in Prokaryote? |
70S, sensitive to streptomycin and chloramphenicol |
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Division of Prokaryote? |
Binary fission |
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Cell wall of Eukaryote? |
Cellulose |
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Chromosome of Eukaryote? |
Multiple & linear
|
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Ribosomes of Eukaryote? |
80S & sensitive to cyclohgeximide |
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Division of Eukaryote? |
Mitosis of meiosis |
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Nuclear envelope & nucleolus in Eukaryote? |
Present |
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DNA to RNA? |
Transcription |
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RNA to protein? |
Translation |
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No. of possible combinations of codons? |
64 4 nucleotides, 3 codo positions = 4 cubed |
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What is the Start codon |
AUG |
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What are the Stop codons? |
UAA, UGA, UAG |
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How did microbial cell life appear? |
- only happened on the ocean floor where environment was less hostile and stable - organic precursors form living cells spontaneoulsy |
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What is Evolution? |
Process by which organisms undergo descent with modification, driven by mutation and selection |
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What is present in the Infant gut? |
Bifidobacteria |
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What is present in the Adult gut? |
Bacteriodetes and firmicutes |
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What is the ocean like compared to freshwater? |
Saline, cooler and low in nutrients |
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What is symbiosis? |
Microorganisms establish relationships with others |
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What is parasitism? |
One member in the relationship is harmed, the other benefits |
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What is mutualism? |
Both species benefit |
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What is Commensalism? |
One species benefits, the other is neither harmed nor helped |
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What is an ecosystem? |
Sum of all organisms and abiotic factors in a particular environment |
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What is a habitat? |
A portion of the ecosystem where a community could reside |
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What is a microenvironment? |
Intermediate environmental surroundings of a microbial cell/group |
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What is a Niche? |
Differences in type and quantity of resources and physiochemical conditions of a habitat define the niche for each microbe |
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What are biofilms? |
Assemblages of bacterial cells adhered to a surface and enclosed in an adhesive matrix excreted by cells |
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What is the soil made up of? |
40% inorganic matter 5% organic matter 50% air and water 5% living organisms |
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What are commensal microorganisms? |
frequently isolated from the human body and not associated with disease |
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What is a pathogen? |
Cause human infection when in the body |
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What is an opportunistic pathogen? |
Commensals that cause infection under certain conditions |
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What is the Germ Theory? |
Many diseases are caused by the presence and actions of specific microorganisms |
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What is an endotoxin? |
Part of the cell wall and only released when cell dies e.g. Meningitis |
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What is an exotoxin? |
Secreted by bacteria and each has a specific effect e.g. vaccines for Tetanus |
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What is an antibiotic? |
A substance produced by one microorganisms, inhibitory to another with selective toxicity |
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What does an antibiotic target in a bacteria? |
Cell wall, protein synthesis, metabolic pathways and DNA synthesis |
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What is Epidemiology? |
Study of the occurrence, distribution and determinants of health and disease in a population |
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How do bacteria divide? |
Binary Fission |
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How do yeasts divide? |
Budding |
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What is Lag Phase? |
Transition phase for organisms to adjust to new environment |
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How to have max productivity in industry? |
Minimise lag phase |
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What does Lag phase depend on? |
Status of transferred cells and the previous environment |
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What is exponential phase? |
Period of balanced growth where the biomass is increasing logarithmically |
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What does growth rate depend on? |
Carbon and energy sources, presence and absence of other nutrients, temperature, pH, water availability and oxygen |
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Rate of growth decreases in deceleration phase due to what? |
Nutrient limitation and toxicity or stress |
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What causes stress in the deceleration phase? |
too many organisms, oxygen depletion or overproduction of acid or alcohol |
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What is the Stationary phase? |
Decrease in primary metabolic activity and production of secondary metabolites |
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What happens when theres a decrease in cell viability? |
Cell walls start to leak and death |
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What is pH? |
Change in hydrogen ion concentration |
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How can some organisms withstand extreme conditions? |
Adjustments to lipid content of membrane and enzymes |
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What is water availability? |
Ratio of the vapour pressure to the air in equilibrium with a solution to the vapour pressure of pure water |
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What is osmosis? |
Water diffuses from high water concentration to low water concentration across a semi-permeable membrane |
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What are compatible solutes? |
Solutes accumulated by organisms at low Aw allow uptake of water by osmosis in the cell, non-inhibitory to biochemical processes within the cell |
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What is a halophile? |
Require sodium ion |
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What is an extreme halophile? |
Live at high salt concentrations |
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What does Halotolerant mean? |
Don't require high sodium levels but can tolerate it |
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What are osmophiles? |
Live at high sugar concentrations? |
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What are Xerophiles? |
Live in very dry environments |
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What is oxygen metabolism? |
Reduction of oxygen to water |
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What are obligate anaerobes? |
Killed by oxygen and don't possess enzymes |
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What are aerotolerant anaerobes? |
Oxygen not required but tolerated |
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What are obligate aerobes? |
Cant grow in the absence of oxygen |
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What are facultative aerobes? |
Switch between aerobic and anaerobic |
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What enzyme can destroy Superoxide? |
Superoxide dismultase |
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What enzyme can destroy Hydrogen peroxide? |
Catalase peroxidase |
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What are capsomeres? |
repeating subunits |
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What is a bacteriophage? |
Virus that infects bacteria |
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What is a viron? |
Small infectious unit |
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What is a viroid? |
infectious RNA |
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What are prions? |
Proteinaceous infectious agents |
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Stages of replication for viruses? |
Attachment, penetration, synthesis, assembly and release |
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What is the eclipse phase? |
Attachment to synthesis |
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What is the latent phase? |
Attachment to maturation |
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What are the functions of Bacteria? |
Independent metabolism, growth and reproduction, differentiation, communication, movement and evolution |
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How does penicillin work? |
Binds trans-peptides and prevents formation of bonds in oligopeptides, inhibiting bacterial cell wall synthesis |
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Function of the cell wall? |
Provide rigidity and shape, resistance to environmental factors, pathogenicity and interactions with other organisms |
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What is a spheroplast? |
Bacterial cell without a cell wall |
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How can water activity of food product be reduced? |
Drying, lyophilisation and addition of salt or sugar |
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What is Pasteurisation? |
Destruction of vegetative cells only and cause a reduction in microbial number |
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Why is the environment in a tin anaerobic? |
There is growth due to activity of fermentative organisms which leads to gas production and causes distortions in the shape of the can, this shows its unsafe to eat |
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What are chemical food preservations? |
Chemical antimicrobial agents that interfere with cell permeability, enzyme activity and genetic mechanism |
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What is potentially detrimental to human health? |
Nitrites, ethylene and propylene oxides and antibiotics |
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How is Insulin used? |
Human insulin amino acid sequence is known so DNA is synthesised and inserted into E.coli, the genes are expressed and polypeptide chains form proteins invitro |
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What is Anabolism? |
Sum of biochemical processes towards the synthesis of cell constituents from simpler molecules and requires energy |
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What is Catabolism? |
Sum of biochemical processes leading to breakdown of complex compounds to simple substances, releasing energy |
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Main features of chemical reactions outside living cells? |
Occur spontaneously without control and are very rapid |
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Main features if bio-chemical reactions inside living cells? |
Occur in a certain order and in certain compartments of the cell under strict control due to presence of regulatory mechanisms and are relativlely slow due to biological catalysts |
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What are Macronutrients? |
Required in large amounts |
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What are micronutrients? |
Required in small amounts |
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How do prokaryotes get nutrition? |
They don't have specialised structures for nutrition and so the whole prokaryote cell is involved in nutrition all the time during reproduction |
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What happens when nutrition is limited due to lack of nutrients? |
Bacterial growth is inhibited and many undergo sporulation |
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What do chemotrophs do? |
Oxidise a broad range of organic and inorganic compounds to produce ATP |
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What are the microorganisms that deal with organic chemicals known as? |
Chemoorganotrophs |
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What are the microorganisms that deal wit inorganic chemicals known as? |
Chemolithotrophs |
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What are Autotrophs? |
Use inorganic carbon dioxide as a single source of carbon |
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What are Heterotrophs? |
Require on or more organic compounds as a source of carbon |
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What are the two major forms of Autotrophy? |
Oxygenic photosynthesis and Anoxygenic photosynthesis |
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What processes are involved with catabolism? |
Fermentation and respiration |
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What is Fermentation? |
Anaerobic catabolism in which an organic substance serves as a donor and acceptor of electrons. ATP is produced by substrate level phosphorylation |
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What is Respiration? |
Catabolism where organic substance is oxidised by oxygen or substitute as electron acceptor. ATP is produced by oxidative phosphorylation |
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What is Glycolysis? |
Catabolism of glucose to pyruvate |
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What is Carbon needed for? |
Component for all macromolecules |
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What is Nitrogen needed for? |
Included into proteins, nucleic acids and others |
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What is phosphorus needed for? |
Nucleic acids and phospholipids |
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What is Sulfur needed for? |
For amino acids, vitamins and coenzyme A |
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What is Potassium needed for? |
Many enzymes for protein synthesis |
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What is Magnesium needed for? |
Stability of ribosomes, membranes and nucleic acids and for activity of enzymes |
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What is Calcium needed for? |
Stabilises cell walls and helps thermo-resistance of endospores |
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What is Iron needed for? |
Role in respiration as a component in cytochromes |
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What are Siderophores? |
Different organic compounds that bind iron and transport it into cells |
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What is the use of selective, differential and enriched media? |
For the isolation of particular species and for comparative studies of microorganisms |
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What is the use of Solid media? |
For isolation and maintenance of pure microbial cultures, they immobile cells allowing them to grow and form visible isolated colonies |
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What is the use of Liquid media? |
For rapid and large scale cultivation of pure cultures |
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Who named the enigmatic square archaeon? |
A.E.Walsby |
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How do Legumes and nitrogen fixing bacteria do symbiosis? |
The plant provides energy source needed by the root nodule bacteria and the bacteria provide fixed nitrogen for the growth of the plant |
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Tumour Induction> |
Crown galls (tumours) induced by Ti-plasmids |
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Root Induction> |
Hair roots induced by Ri-plasmids |
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What are catabolic plasmids? |
They code for enzyme degrading xenobiotics |
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What do purple sulfur bacteria do? |
Utilise hydrogen sulfide as an electron donor for carbon dioxide reduction in photosynthesis |
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What are Streptomyces? |
Large group of aerobic, gram positive bacteria that form spores at the end of branched filaments |
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How are spores produced in Streptomyces? |
By the formation of cross-walls in the multinucleate sporophores |
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What is Hyperthermophily? |
Groups near the root that have the ability to grow at very high temperatures |
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What is a halo bacterium? |
Contains pink light absorbing pigment and can make ATP using light |
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How to survive at high temperatures? |
Have high cellular solute levels and folding of the protein membrane |
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What are chaperonins? |
Hyperthermophiles produce them that function only at the highest growth temperatures |
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What is Thermosome? |
A protein complex which allows to keep cellular proteins properly folded |
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What is reverse DNA gyrase? |
All hyperthermophiles produce this DNA topoisomerase that introduces positive super coils into DNA |
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What are archaeal histons? |
DNA binding proteins that wind and compact DNA into nucleosome like structures |
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What are characteristics of Fungi? |
Eukaryotic hetertrophs and choose between being uni and multi cellular. They produce spores through sexual and asexual life cycles |
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What are Saprotrophs? |
Break down and absorb nutrients from dead organic matter |
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What are cell walls of fungi made of? |
Chitin |
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What is a mycelium? |
Made of many hyphae that infiltrates the material on which fungi feed and its structure maximises its surface to volume ratio |
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What is a septum? |
Allows exchange of materials between different fungal cells within the hypha |
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What are Septate hypha? |
Hyphae are divided into cells by cross walls with pores allowing cell to cell movement of organelles |
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What are Coenocytic hypha? |
Continuous cytoplasmic mass having many nuclei |
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What are Haustoria? |
Hypha that allow some unique fungi to feed on living organisms |
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What are Mycorrhizae? |
Mutual beneficial relationship between fungi and plant roots |
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What is the role of fungi and plant with symbiosis? |
Fungi improves delivery of phosphorus and other minerals to plants from soils and the plant supply fungi with organic nutrients |
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What are the 5 phyla of Fungi? |
Chytrindiomycota, Glomeromycota, Zygomycota, Ascomycota and Basidiomycota |
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What are Chytrids? |
Found in freshwater and terrestrial habitats, have flagellated spores, found in the digestive tract of cattle and are parasites |
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What are Zgomycetes? |
Include fast growing moulds, parasites, symbionts and hyphae are coenocytic. Carry out asexual production of haploid spores |
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What are Glomeromycetes? |
Nearly all form arbuscular mycorrhizal (extend hyphae through cell walls of roots) |
|
What are Ascomycetes? |
Live in marine, freshwater and terrestrial habitats and produce sexual spores in a sac like asci contained in fruiting bodies called ascocarps |
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What are Basidiomycetes? |
Important as decomposers of wood and fungi and fruiting bodies are dykariotic mycelium |
|
How do fungi reproduce asexually? |
By growth and spread of hypha filaments, production of spores by mitosis or simple cell division such as budding |
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How do fungi reproduce sexually? |
Three stages of plasmogamy, karyogamy and meiosis |
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What happens in plasmogamy? |
the cytoplasm of two compatible parent hyphae fuses together but without fusion of the nucleus |
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What happens in Karyogamy? |
Fusion of these haploid nuclei and formation of a diploid nucleus |
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What happens in meiosis? |
Cell division that reduced the chromosome number to one set per cell, restoring the haploid phase. |
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What are miospores? |
How haploid nuclei are incorporated into spines |
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What are the stages of biofilm dispersal? |
Attachment, colonisation, development and dispersal |
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Why live in a biofilm? |
Protects cells from predation, desiccation, antibiotics, has increased resistance to disinfectants and can capture and concentrate nutrients |
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What are nosocomial infections? |
Infections acquired by patients during hospitilisation |
|
What can happen to immunecomprimised patients? |
oppertunistic pseudomonas may cause disease as the immune system is already impaired |
|
Psuedomonas aeruginosa |
lung infection in cystic fibrosis |
|
What are attachment blockers? |
They prevent cells of periodontal pathogens joining the biofilm |
|
How was sand used for the filtration systems in 1860s ? |
The filter medium (sand) presents surfaces for the microbes to attach to and feed on the organic material in the water being treated |
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.What devices are there to study biofilms? |
Rotating disc reactor, CDC biofilm reactor and propella reactor |
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What is sequencing? |
Determining the precise order of nucleotides in a DNA molecule for its identification |
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What is the aim of fixation? |
Presentation of autolysis, microbial degradation, enables subsequent staining techniques and fixes cells close to their living state |
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What is the Papanicolaou method? |
Haomatoxylin staining of nucleus with two cytoplasmic counter staining |
|
What is Romanowsky staining? |
Haematological stains for cells from serous fluids |
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What is Immunocytochemistry? |
Cytological detection of specific cells constituents based on their antigenic structure |
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What are valve-type processes? |
Cells are placed in stainless steel container and a tight fitting piston is inserted and high pressures are applied to force cells through a small hole |
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What is Sonication? |
A solicitor can be immersed directly into a cell suspension. It's vibrated and high frequency sound waves disrupt cells. |
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What is Homogenisation? |
Cells are placed in a closed vessel, a tight fitting plunger is inserted and rotated with a downward force. Cells are disrupted as they pass between the plunger and vessel wall |
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What happens when a centrifugal force is applied to an aqueous mixture? |
Components of larger size and density will sediment faster |
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Low speed centrifugation? |
Used to separate intact cells from medium |
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High speed centrifugation? |
Can be used to separate sub cellular components |
|
What does the sedimentation velocity of a particle depend on? |
Its mass, a more massive particle sediments more rapidly. Shape affects the viscous drag. Dense particle moves more rapidly than a less dense one. Density of the solution. |
|
What does Gel-filtration depend on? |
Bead diameter, pore size, salt concentration, column volume and flow rate |