Biotechnology and Gene Technologies Flashcards
What is aseptic technique?
Any measure taken at any point in a biotechnological process to ensure that unwanted microorganisms do not contaminate the culture that is being grown or the products that are extracted
What is biotechnology?
The industrial use of living organisms (or parts of them) to produce food, drugs, or other products
What is a culture?
A growth of microorganisms.
This may be a single species (pure culture), or a mixture of species (mixed culture)
Microorganisms can be cultured in a liquid such as nutrient broth, or on a solid surface such as nutrient agar gel
Primary metabolites
Substances produced by an organism as part of its normal growth
They include amino acids, proteins, enzymes, nucleic acids, ethanol and lactate
The production of primary metabolites matches the growth in population of the organism
What are secondary metabolites?
Substances produced by an organism that are not part of its normal growth
The antibiotic chemicals produced by a number of microorganisms are almost all secondary metabolites
The production of secondary metabolites usually begins after the main growth period of the organisms and so does not match the growth in population of the organism
What happens during lag phase of the standard growth curve?
Organisms are adjusting to the surrounding conditions. This may mean taking in water, cell expansion, activating specific genes, and synthesising specific enzymes
The cells are active, but not reproducing so population remains fairly constant.
The length of this period depends on the growing conditions
What happens during log phase of the standard growth curve?
The population size doubles each generation as every individual has enough space and nutrients to reproduce
In some bacteria, for example, the population can double every 20-30 minutes in these conditions
The length of this phase depends on how quickly the reproduce and take up the available nutrients and space
What happens during stationary phase of the standard growth curve?
Nutrient levels decrease and waste products like carbon dioxide and other metabolites build up. Individual organisms die at the same rate at which the new individuals are being produced
In an open system, this would be the carrying capacity of the environment
What happens during decline (death) phase of the standard growth curve?
Nutrient exhaustion and increased levels of toxic waste products and metabolites lead to the death rate increasing above the reproduction rate
Eventually, all organisms will die in a closed system
Define electrophoresis
Separation of different lengths of DNA fragments, in a mixture, is achieved because as the negatively charged fragments move towards the positive electrode, shorter fragments pass through the gel more easily and so move further in a fixed time.
Similar to chromatography.
Define Genomics
Study of the whole set of genetic information in the form of DNA sequences that occur in the cells of organisms of a particular species.
The sequenced genomes of organisms are place on public access databases
What are primers?
Short, single stranded sequences of DNA, around 10-20 bases in length.
They are needed in sequencing reactions, to bind to a section of DNA because the DNA polymerase enzyme cannot bind directly to single stranded DNA fragments
Explain why asexual reproduction is quicker than sexual reproduction
Asexual reproduction does not require the development of sex organs or specialised haploid gametes.
The organism does not need to release male gametes, nor do cells need to be transferred to another individual
What advantages are there for elm trees of the capacity to reproduce both sexually and asexually?
Sexual reproduction leads to offspring showing genetic variety. This has advantages in long term survival of the species in terms of allowing adaptation to changes in the environment.
Being able to reproduce asexually too allows for the production of offspring even if there are no other individuals of the same species sufficiently close by, or if the production of seed fails
Explain why asexual reproduction in plants is described as vegetative propagation
Asexual reproduction in plants uses vegetative structures i.e. structures that are a normal part of the growing organism, often associated with overwintering, not separate sex organs
