F215 Flashcards
What are the advantages of immobilising enzymes?
- Enzymes are not present with products so there are low purification costs
- Enzymes are immediately available for reuse (important in continuous processes)
- Immobilised enzymes are more stable because whatever is used to immobilise them also protects them
What are the disadvantages of immobilised enzymes?
- Immobilisation requires additional time, equipment and materials so it is expensive
- Immobilised enzymes can be less active because they do not mix freely with substrate
- Contamination would cause the whole system to be stopped
What are the types of immobilisation?
Adsorption, Covalent Bonding, Entrapment, Membrane Separation
What is the function of homeobox genes?
They control the development of the body plan of an organism
What is immobilisation? (Of enzymes)
A technique where enzymes are held/separated from the reaction mixture
Outline the process of Apoptosis
- Enzymes break down the cell cytoplasm
- The cytoplasm becomes dense with organelle tightly packed
- The cell surface membrane changes and blebs form
- The chromatin condenses and the nuclear envelope beaks DNA into fragments
- The cell breaks down into vesicles that are taken up by phagocytosis and cellular debris is disposed of so that it doesn’t damage other cells or tissue
What is the difference between reproductive cloning and non-reproductive cloning?
- Reproductive cloning is the production of offspring which are genetically identical to mother (nuclear transfer) or to their siblings (splitting embryos)
- Non-reproductive cloning is the use of stem cells in order to generate replacement cells, tissues or organs (maybe be used to treat particular diseases or conditions in of humans)
Describe the production of artificial clones of plants from tissue culture
- A small cutting it taken from the plant to be cloned (the explant)
- Explant is placed on a nutrient growth medium
- Cells in the tissue divide but do not differentiate. Instead they form a mass of undifferentiated cells called a callus
- After some time, single callus cells can be removed from the mass and placed on growing medium containing plant hormones that encourage shoot growth
- After more time, the growing shoot are transferred onto the a different growth medium that encourages root growth
- The growing plants are then transferred to a green house to get acclimatised before being planted
Advantages of cloning animals
- High value animals e.g. Cows for high milk yield, can be cloned in high numbers
- Rare animals can be cloned to preserve the species
- Genetically modified animals e.g. Sheep that produce pharmaceutical chemicals in their milk, can be produced quickly
Disadvantages of cloning animals
- High value animals are not necessarily produced with animal welfare in mind
- Lack of genetic variation in plants means that they are more likely to die because they cannot adapt to changes in the environment
- Animals cloned using nuclear Marietta of adult cells may not remain healthy for very long
What is the Lag Phase?
Microorganism is adjusting to the surrounding conditions
What is the log phase/exponential phase?
The population size doubles each generation as each individual has enough space and nutrients to divide
What is the stationary phase?
- Nutrient levels decrease and waste products (like CO2) build up
- Individual organisms die at the same rate as new individuals are being produced
What is the death phase?
Nutrients are being used up and high levels of toxic waste products and metabolites leads to the death rate rising higher than the reproduction rate
What is adsorption?
Enzyme molecules are mixed with the immobilising support and bind to it due to a combination of hydrophobic interactions and ionic links
