Biotechnology Flashcards
List the main characteristics of a typical bioprocess that distinguish it from a typical chemical
process.
Take place at ambient temperature.
Involve labile products, heat and extreme pH sensitive.
Run in batch or batch-fed mode.
Usually performed in sterile conditions.
Need containment of cells used.
Involve an aqueous stage and involve large amounts of water.
Require a higher degree of product purity.
Small volume, high value.
List the typical downstream processing problems associated with bioprocesses.
Separation of products for purification.
Cell disintegration for intracellular products.
Product formulation and preparation for sales.
Wastewater treatment.
List and explain briefly the main stages in a typical bioprocess
Medium (nutrients) formulation and raw
materials preparation.
Sterilisation of medium, bioreactor and ancillaries
Inoculum (seed culture) development (from
small to large quantities)
Bioreactor (fermentation/biocatalysis/product
formation) operation
Product recovery and purification
Product formulation and preparation of product
for sales
Waste treatment/management
What is the classification of cells based on their basic cell structure?
There are prokaryotes (bacteria and archea) and eukaryotes.
What are the characteristics of prokaryotes?
Prokayotes lack a nucleus and membrane organelles, include bacteria and cyanobacteria.
Draw a schematic representation of the main structural features of a prokaryotic cell.
.
What are the main differences between a prokaryotic cell and a eukaryotic cell?
Eukarotes have a nucleus and organelles within the cell body that are contained in a membrane.
List the four classes of ingredients in the medium composition required for the growth and
multiplication of cells.
Sources of carbon Sources of inorganic chemicals (N, P, S) Energy source Electron acceptor
What are the main macromolecules found in a typical cell?
Proteins (enzymes and stuctural)
Nucleic acids (DNA and RNA)
Polysaccharides (Sugars, carbohydrates and structural)
Phospholipids
List the six major chemical elements found in a typical cell.
Carbon Oxygen Nitrogen Hydrogen Phosphorus Sulphur
What is a macronutrient in a growth medium?
An inorganic nutrient required in large
amounts for growth, such as nitrogen,
potassium, calcium, phosphorus, magnesium,
and sulfur.
What is a micronutrient in a growth medium?
An inorganic nutrient required in only small
amounts for growth such as, iron, chlorine,
copper, manganese, zinc, molybdenum, and
boron.
Why do we need to sterilise media and equipment before starting a pure culture of cells?
To remove the possibility of there being unwanted foreign organisms within the reaction space that could reduce the growth capabilities of the required reactant.
List the sterilisation techniques for equipment and media
Sterilisation can be achieved by heat,
radiation (gamma), chemical means (e.g.
sodium metabisulfite, sodium hypochlorite) or
by filtration through sub-micron membranes.
Explain briefly what enzymes are and how they work in the cell.
Enzymes are complex protein structures made up of many different amino acids. They catalyse metabolic reactions within a cell by lowering the activation energy of a reaction.
Using sketches, explain briefly the “Lock-and-Key Model” and “Induced-Fit Model” for enzyme
action
.
Starting from the instantaneous mass balance on the enzyme-substrate complex, derive the
Michaelis-Menten equation that describes simple enzyme kinetics. Include in your answer
definitions for V, Vmax, [S] and KM
.
Explain briefly how initial rates can be obtained for a single enzyme-single substrate reaction
You would plot a graph of Product concentration over time and use the initial, most likely linear, gradient to find the initial rate.
Explain the Lineweaver-Burk plot (also called the double reciprocal plot) for the graphical
determination of the parameters of the Michaelis-Menten expression for enzyme kinetics from a
set of experimental initial rate data.
Taking the reciprocal of the Michaelis-Menten expression we are able to produce a linear equation for use on a graph. The gradient of the graph will be Km/vm so we can easily find Km, the concentration of substrate when the reaction is at half its rate.
What are the requirements for growth and division (multiplication) of a cell culture?
Sterilised nutrients Maintain correct pH, temperature and pressure Add air (sparge) or other gases as required
Using a sketch, explain briefly various phases of microbial growth in a typical batch culture.
Lag-Acceleration-Exponential-Deceleration- Stationary-Death
Write a general mass balance for a batch bioreactor (using y to indicate any compound).
.
Define the volumetric rate in “biochemical engineering”
The amount of material produced or used up, per volume, per time
Define the specific rate in “biochemical engineering”.
Volumetric rate/Viable biomass concentration
