Biology a Level F215

Topics: DNA, Bacteria, Molecular biology Pages: 9 (2100 words) Published: June 18, 2013
* State the biotechnology is the industrial use of living organisms to produce food, drugs of other products * Explain why microorganisms are used in biotechnological processes * Describe the standard growth curve in closed culture

* Compare and contrast the processes of batch and continuous culture * Describe the difference between primary and secondary metabolites * Describe the importance of manipulating the growing conditions in a fermentation vessel in order to maximise the yield

* Industrial use of living organisms to make products for human use * Products include: drugs, food and enzymes
* Used in agriculture, food science, medicine and animal husbandry * Microbes are mainly used (ie: bacteria, fungi or protoctista)

* +’s of using microbes:
* Rapid life cycle
* Grow rapidly in optimum conditions
* Asexual reproduction is used in many bacteria * ˳˚˳ genetically identical
* Secrete proteins out of cells ˳˚˳ easily harvested * Can be genetically modified by genetic engineering * ˳˚˳ can produce human proteins such as insulin * Simple growth requirements can be maintained in a fermenter * Can be grown in any climate inside a fermenter * Product is purer (ie: free from chemical contamination compared to chemical synthesis in labs) * Can be given “waste” food materials (eg: potato peelings) * No/very few ethical problems of industrial microbe use

* Population growth of bacterial culture in a closed system:

* 0-8 = LAG phase:
* Initial slow rate of population growth
* Slow because initial low number of individuals * ˳˚˳ doubling by mitosis = relatively small increases * Bacteria have to acclimatise to conditions
* Eg) synthesise enzymes needed to hydrolyse nutrients in the culture * 8-24= LOG/Exponential Phase:
* Very rapid population growth
* Rate of reproduction exceeds death rate
* Optimum conditions for growth (eg: nutrients available) * 24-25= deceleration phase:
* Rate of increase is in decline
* 1 0r more factors in becoming limiting
* 25-30= Stationary phase:
* Population is stable
* Rate of production=rate of death
* 30-end= Death phase:
* Population decreases to ) only in a closed system * Death rate exceeds reproductive rate
* Bacteria die because:
* Lack of nutrients
* ˳˚˳ no aerobic respiration due to no ATP for metabolism * Lack of O2 ˳˚˳ no aerobic respiration
* ˳˚˳ lactic acid/ethanol are made from anaeroib respiration = toxic * Build up of wastes eg) CO2
* ˳˚˳ low pH
* ˳˚˳ enzymes are denatured
* Excess heat is produced from many reactions (respiration) * ˳˚˳ enzymes are denatured
* Industrial scale fermenters (see diagram)
* Fermenters are open systmes ie) allowing inputs and outputs * These are large structures the size of a 2 storey buildig * Conditions are kept to optimum for mirobes
* 2 types:
* Continuous Culture:
* products made are removed at regular intervals ˳˚˳ micrboes remain in the LOG phase * nutrients are added regularly
* used to generate primary metabolites ie) products of metabolism made during the main growth phase (LOG) * any protiens secreted by cells including those made due to genetic engineering * eg) insulin

* Batch Culture:...
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