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173 Cards in this Set

  • Front
  • Back

Nuclear pore & nucleolus in Prokaryote?

Absent

Cell wall of a Prokaryote?

Peptidoglycan

Chromosome in Prokaryote?

Single & circular

Ribosomes in Prokaryote?

70S, sensitive to streptomycin and chloramphenicol

Division of Prokaryote?

Binary fission

Cell wall of Eukaryote?

Cellulose

Chromosome of Eukaryote?

Multiple & linear


Ribosomes of Eukaryote?

80S & sensitive to cyclohgeximide

Division of Eukaryote?

Mitosis of meiosis

Nuclear envelope & nucleolus in Eukaryote?

Present

DNA to RNA?

Transcription



RNA to protein?

Translation

No. of possible combinations of codons?

64


4 nucleotides, 3 codo positions = 4 cubed

What is the Start codon

AUG

What are the Stop codons?

UAA, UGA, UAG

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

What is Evolution?

Process by which organisms undergo descent with modification, driven by mutation and selection

What is present in the Infant gut?

Bifidobacteria

What is present in the Adult gut?

Bacteriodetes and firmicutes

What is the ocean like compared to freshwater?

Saline, cooler and low in nutrients

What is symbiosis?

Microorganisms establish relationships with others

What is parasitism?

One member in the relationship is harmed, the other benefits

What is mutualism?

Both species benefit

What is Commensalism?

One species benefits, the other is neither harmed nor helped

What is an ecosystem?

Sum of all organisms and abiotic factors in a particular environment

What is a habitat?

A portion of the ecosystem where a community could reside

What is a microenvironment?

Intermediate environmental surroundings of a microbial cell/group

What is a Niche?

Differences in type and quantity of resources and physiochemical conditions of a habitat define the niche for each microbe

What are biofilms?

Assemblages of bacterial cells adhered to a surface and enclosed in an adhesive matrix excreted by cells

What is the soil made up of?

40% inorganic matter


5% organic matter


50% air and water


5% living organisms

What are commensal microorganisms?

frequently isolated from the human body and not associated with disease

What is a pathogen?

Cause human infection when in the body

What is an opportunistic pathogen?

Commensals that cause infection under certain conditions

What is the Germ Theory?

Many diseases are caused by the presence and actions of specific microorganisms

What is an endotoxin?

Part of the cell wall and only released when cell dies


e.g. Meningitis

What is an exotoxin?

Secreted by bacteria and each has a specific effect


e.g. vaccines for Tetanus

What is an antibiotic?

A substance produced by one microorganisms, inhibitory to another with selective toxicity

What does an antibiotic target in a bacteria?

Cell wall, protein synthesis, metabolic pathways and DNA synthesis

What is Epidemiology?

Study of the occurrence, distribution and determinants of health and disease in a population

How do bacteria divide?

Binary Fission

How do yeasts divide?

Budding

What is Lag Phase?

Transition phase for organisms to adjust to new environment

How to have max productivity in industry?

Minimise lag phase

What does Lag phase depend on?

Status of transferred cells and the previous environment

What is exponential phase?

Period of balanced growth where the biomass is increasing logarithmically

What does growth rate depend on?

Carbon and energy sources, presence and absence of other nutrients, temperature, pH, water availability and oxygen

Rate of growth decreases in deceleration phase due to what?

Nutrient limitation and toxicity or stress

What causes stress in the deceleration phase?

too many organisms, oxygen depletion or overproduction of acid or alcohol

What is the Stationary phase?

Decrease in primary metabolic activity and production of secondary metabolites

What happens when theres a decrease in cell viability?

Cell walls start to leak and death

What is pH?

Change in hydrogen ion concentration

How can some organisms withstand extreme conditions?

Adjustments to lipid content of membrane and enzymes

What is water availability?

Ratio of the vapour pressure to the air in equilibrium with a solution to the vapour pressure of pure water

What is osmosis?

Water diffuses from high water concentration to low water concentration across a semi-permeable membrane

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

What is a halophile?

Require sodium ion

What is an extreme halophile?

Live at high salt concentrations

What does Halotolerant mean?

Don't require high sodium levels but can tolerate it

What are osmophiles?

Live at high sugar concentrations?

What are Xerophiles?

Live in very dry environments

What is oxygen metabolism?

Reduction of oxygen to water

What are obligate anaerobes?

Killed by oxygen and don't possess enzymes

What are aerotolerant anaerobes?

Oxygen not required but tolerated

What are obligate aerobes?

Cant grow in the absence of oxygen

What are facultative aerobes?

Switch between aerobic and anaerobic

What enzyme can destroy Superoxide?

Superoxide dismultase

What enzyme can destroy Hydrogen peroxide?

Catalase peroxidase

What are capsomeres?

repeating subunits

What is a bacteriophage?

Virus that infects bacteria

What is a viron?

Small infectious unit

What is a viroid?

infectious RNA

What are prions?

Proteinaceous infectious agents

Stages of replication for viruses?

Attachment, penetration, synthesis, assembly and release

What is the eclipse phase?

Attachment to synthesis

What is the latent phase?

Attachment to maturation

What are the functions of Bacteria?

Independent metabolism, growth and reproduction, differentiation, communication, movement and evolution

How does penicillin work?

Binds trans-peptides and prevents formation of bonds in oligopeptides, inhibiting bacterial cell wall synthesis

Function of the cell wall?

Provide rigidity and shape, resistance to environmental factors, pathogenicity and interactions with other organisms

What is a spheroplast?

Bacterial cell without a cell wall

How can water activity of food product be reduced?

Drying, lyophilisation and addition of salt or sugar

What is Pasteurisation?

Destruction of vegetative cells only and cause a reduction in microbial number

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

What are chemical food preservations?

Chemical antimicrobial agents that interfere with cell permeability, enzyme activity and genetic mechanism

What is potentially detrimental to human health?

Nitrites, ethylene and propylene oxides and antibiotics

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

What is Anabolism?

Sum of biochemical processes towards the synthesis of cell constituents from simpler molecules and requires energy

What is Catabolism?

Sum of biochemical processes leading to breakdown of complex compounds to simple substances, releasing energy

Main features of chemical reactions outside living cells?

Occur spontaneously without control and are very rapid

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

What are Macronutrients?

Required in large amounts

What are micronutrients?

Required in small amounts

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

What happens when nutrition is limited due to lack of nutrients?

Bacterial growth is inhibited and many undergo sporulation

What do chemotrophs do?

Oxidise a broad range of organic and inorganic compounds to produce ATP

What are the microorganisms that deal with organic chemicals known as?

Chemoorganotrophs

What are the microorganisms that deal wit inorganic chemicals known as?

Chemolithotrophs

What are Autotrophs?

Use inorganic carbon dioxide as a single source of carbon

What are Heterotrophs?

Require on or more organic compounds as a source of carbon

What are the two major forms of Autotrophy?

Oxygenic photosynthesis and Anoxygenic photosynthesis

What processes are involved with catabolism?

Fermentation and respiration

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

What is Respiration?

Catabolism where organic substance is oxidised by oxygen or substitute as electron acceptor. ATP is produced by oxidative phosphorylation

What is Glycolysis?

Catabolism of glucose to pyruvate

What is Carbon needed for?

Component for all macromolecules

What is Nitrogen needed for?

Included into proteins, nucleic acids and others

What is phosphorus needed for?

Nucleic acids and phospholipids

What is Sulfur needed for?

For amino acids, vitamins and coenzyme A

What is Potassium needed for?

Many enzymes for protein synthesis

What is Magnesium needed for?

Stability of ribosomes, membranes and nucleic acids and for activity of enzymes

What is Calcium needed for?

Stabilises cell walls and helps thermo-resistance of endospores

What is Iron needed for?

Role in respiration as a component in cytochromes

What are Siderophores?

Different organic compounds that bind iron and transport it into cells

What is the use of selective, differential and enriched media?

For the isolation of particular species and for comparative studies of microorganisms

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

What is the use of Liquid media?

For rapid and large scale cultivation of pure cultures

Who named the enigmatic square archaeon?

A.E.Walsby

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

Tumour Induction>

Crown galls (tumours) induced by Ti-plasmids

Root Induction>

Hair roots induced by Ri-plasmids

What are catabolic plasmids?

They code for enzyme degrading xenobiotics

What do purple sulfur bacteria do?

Utilise hydrogen sulfide as an electron donor for carbon dioxide reduction in photosynthesis

What are Streptomyces?

Large group of aerobic, gram positive bacteria that form spores at the end of branched filaments

How are spores produced in Streptomyces?

By the formation of cross-walls in the multinucleate sporophores

What is Hyperthermophily?

Groups near the root that have the ability to grow at very high temperatures

What is a halo bacterium?

Contains pink light absorbing pigment and can make ATP using light

How to survive at high temperatures?

Have high cellular solute levels and folding of the protein membrane

What are chaperonins?

Hyperthermophiles produce them that function only at the highest growth temperatures

What is Thermosome?

A protein complex which allows to keep cellular proteins properly folded

What is reverse DNA gyrase?

All hyperthermophiles produce this DNA topoisomerase that introduces positive super coils into DNA

What are archaeal histons?

DNA binding proteins that wind and compact DNA into nucleosome like structures

What are characteristics of Fungi?

Eukaryotic hetertrophs and choose between being uni and multi cellular. They produce spores through sexual and asexual life cycles

What are Saprotrophs?

Break down and absorb nutrients from dead organic matter

What are cell walls of fungi made of?

Chitin

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

What is a septum?

Allows exchange of materials between different fungal cells within the hypha

What are Septate hypha?

Hyphae are divided into cells by cross walls with pores allowing cell to cell movement of organelles

What are Coenocytic hypha?

Continuous cytoplasmic mass having many nuclei

What are Haustoria?

Hypha that allow some unique fungi to feed on living organisms

What are Mycorrhizae?

Mutual beneficial relationship between fungi and plant roots

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

What are the 5 phyla of Fungi?

Chytrindiomycota, Glomeromycota, Zygomycota, Ascomycota and Basidiomycota

What are Chytrids?

Found in freshwater and terrestrial habitats, have flagellated spores, found in the digestive tract of cattle and are parasites

What are Zgomycetes?

Include fast growing moulds, parasites, symbionts and hyphae are coenocytic. Carry out asexual production of haploid spores

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

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

How do fungi reproduce sexually?

Three stages of plasmogamy, karyogamy and meiosis

What happens in plasmogamy?

the cytoplasm of two compatible parent hyphae fuses together but without fusion of the nucleus

What happens in Karyogamy?

Fusion of these haploid nuclei and formation of a diploid nucleus

What happens in meiosis?

Cell division that reduced the chromosome number to one set per cell, restoring the haploid phase.

What are miospores?

How haploid nuclei are incorporated into spines

What are the stages of biofilm dispersal?

Attachment, colonisation, development and dispersal

Why live in a biofilm?

Protects cells from predation, desiccation, antibiotics, has increased resistance to disinfectants and can capture and concentrate nutrients

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

.What devices are there to study biofilms?

Rotating disc reactor, CDC biofilm reactor and propella reactor

What is sequencing?

Determining the precise order of nucleotides in a DNA molecule for its identification

What is the aim of fixation?

Presentation of autolysis, microbial degradation, enables subsequent staining techniques and fixes cells close to their living state

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

What is Immunocytochemistry?

Cytological detection of specific cells constituents based on their antigenic structure

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

What is Sonication?

A solicitor can be immersed directly into a cell suspension. It's vibrated and high frequency sound waves disrupt cells.

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

What happens when a centrifugal force is applied to an aqueous mixture?

Components of larger size and density will sediment faster

Low speed centrifugation?

Used to separate intact cells from medium

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