Intro to bioengineering Flashcards
What are the factors which affect growth of micro-organisms?
FAT TOM: F ood A cidity (conc.) T emp. T ime O xygen M oisture also: -Sources of carbon -Electron acceptors
How do Bacteria grow?
- Can grow to high concentrations, 100kgm^-3
- Growth rate can be extremely rapid (around 20minutes to double)
-Dependent on adequate transfer of nutrients, products and heat
How do fungi (yeasts) grow?
- Yeasts grow in colonies of single cells (oblate shaped)
- Many can grow in the absence of oxygen, anaerobic (facultative w.t.r to oxygen)
- Larger in size than bacteria (2-12micrometers)
- Can grow to high cell concentrations, 100kgm^-3
- Grow slightly more slowly than bacteria (1.2hours min. to double)
Give an example of a bioprocess that is anaerobic and one that is aerobic
- Anaerobic, production of alcohol with yeast (fermentation)
- Aerobic, production of yeasts for baking
What is the equation for alcohol fermentation?
C6H12O6 + 2ADP -> 2CH3CH2OH + 2CO2 + 2ATP
How do fungi (mushrooms) grow?
- Grow as highly branched networks of microbes (hyphae) to form mycelium
- Can become very dense in volume when grown in suspended cultures
- Can make the culture very thick, high viscosity
- Fairly slow growth, 3-4hrs min to double
- Only aerobic
How do animal cells grow?
- Difficult to grow
- Large, 12-20micrometers
- Fragile
- Complex nutrient requirements
- Slow growth, 12-25h min to double
- Highly susceptible to contamination by faster growing fungi and bacteria
How do plant cells grow?
- Very large, 20-150 micrometers
- Delicate, although do have cell walls
- Slow growing
- Difficult to maintain in pure cultures
What is the effect of temp. on proteins and on lipid-containing membranes of cells and organelles?
Proteins: high temp. denatures protein
Lipid membranes:
- too low, membranes become rigid and fragile
- too high, membranes become too fluid and can’t contain cell or organelle
From the following microorganisms which works at the coolest, and which at the warmest temp.?
mesophiles, psychrotrophs, thermophiles, hyperthermophiles, psychrophiles
psychrophiles < psychrotrophs < mesophiles < thermophiles < hyperthermophiles
What range do most organisms have pH optima in? and which can very few species grow in?
pH 5-9 is optima for most
Below 2 or above 10 is difficult for most to grow in
For microbial nutrition what do macronutrients do, give some examples?
- Required in large quantities
- Play principal roles in cell structure & metabolism
e.g proteins, carbohydrates
For microbial nutrition what do micronutrients do and give some examples?
- Required in small amounts
- Involved in enzyme function and maintenance of protein structure
e.g manganese, zinc, nickel
What is the chemical composition of cytoplasm?
- 70% water
- Proteins
- 96% of cell is composed from carbon, hydrogen, oxygen, phosphorus and sulphur
What are heterotrophic organisms?
-Organisms which use organic chemicals as a carbon source
What are lithotrophic organisms?
Organisms which use inorganic chemicals as a source of carbon
What is the need for water in cells?
- Essential for growth and maintenance
- Serves as a transport medium, uptake of substrates, nutrients and release of metabolic products, and is an electron acceptor
- Too little moisture results in loss of acitivity
- Too much moisture reduces gas transfer
What is catabolism and examples?
- Reactions where larger molecules break down into smaller ones
- Energy yielding
- Examples: breakdown of carbohydrates, proteins and lipids
-Catabolic reactions results in formation of ATP
What is anabolism and examples?
- Reactions where larger molecules are made from smaller molecules
- Energy requiring
- Biosynthetic pathways
- Examples: synthesis of proteins and construction of phospholipids
-Driven by the Gibbs energy released by hydrolysis of ATP to form ADP or AMP
What types of work do cells use internal energy e.g ATP to do?
- Chemical synthesis of large or complex molecules, growth
- Transport of ionic and neutral substance into or out of cells (endocytosis and exocytosis)
- Mechanical work required for cell division and motion
How are energy requirements within cells met?
-By transferring electrons from substrate to electron acceptor
- Substrate is oxidised
- Electron acceptation is reduced
- Mediated through the action of enzymes
In terms of electron acceptors what is the difference between aerobic and anaerobic processes?
-Aerobic, oxygen=electron acceptor
Substrate + O2 -> biomass + CO2 + H2O + organics
-Anaerobic, other chemical=electron acceptor
Substrate + H2 -> biomass + CH4 + organics
What are aerobes?
Micro-organisms that can extract energy from compounds ONLY in the PRESENCE of oxygen
What are anaerobes?
Micro-organisms that can extract energy from compounds ONLY in the ABSENCE of oxygen
