Cloning & Biotechnology Flashcards
How to take a cutting to clone a plant
- Use a healthy shoot
- Cut the stem @ a slant
- (Between nodes), dip in rooting powder / hormone
- Place in soil / compost & add water
- Cover with a plastic bag & remove some leaves to reduce transpiration
Extra tips for cutting (of plants)
Natural cloning examples
Steps of the production of artificial clones of plants by micropropagation & tissue cultures
- Take a small sample of tissue from the plant you want to clone e.g. meristem tissue from shoot tips
- Sterilise the sample e.g. by immersing it I’m bleach / ethanol
- The explant (material removed from the plant) = placed in a sterile culture medium, containing a bunch of plant hormones e.g. auxins / cytokinins to stimulate mitosis
These cells proliferate, forming a callous (mass of identical cells)
- The callus is divided + individual cells / clumps from it are transferred from, there to a new culture medium, to develop tiny, genetically identical platelets
Pros & cons of artifical cloning in plants
How does natural cloning occur in plants e.g. identical twins!
- an egg is fertilised by a sleep, so the zygote formed, which undergoes all cell cycles -> forms embryos
Sometimes: - embryo splits in two: these form two identical embryos with the same genotype & develop in the uterus
Result = identical offspring, so same gender & phenotype
How do non identical twins form
From separate eggs & sperm, therefore not considered clones
What are the two ways needed to produce clones in animals
Artifical twinning e.g. in cattle
Somatic cell nuclear transfer
What are the steps in artificial twinning
- Individual cow with desirable traits = treated with hormones so she ‘superovulates’, releasing more mature ova than normal
- Ova fertilised normally, or via artificial inseminations & early embryos are gently flushed out of uterus
- Cells still totipotent -> cells of the early embryo are split to produce several smaller embryo
- Each split embryo grown in lab for days, then implanted into a surrogate mother
- Embryos develop into fetuses & are born normally: identical clone produced by different mothers
What are the steps to somatic cell nuclear transfer
- Nuclear removed from a somatic cell of an adult animal
- Nucleus removed from adult somatic cell is placed into the enucleated ovum & given a mild electric shock, so it fuses & begins to divide
- Embryo that develops = transferred to a 3rd animal -> then it develops to them
What is enucleation
Nucleus removed from a mature ovum harvested from a different female animal of the same species
Pros & cons of cloning
Why are microorganisms used in biotechnology
- economic considerations: can be grown on industrial scale
- short life cycle = reproduce quick
- growth requirements:
-> food cheap & readily available
-> occupy very little space
Common processes using biotechnology: bacteria & fungus
Pros & cons of using micro-organisms in food
Examples of asceptic techniques
Culturing method steps
1) Pour sterile agar into petri dish, cover w/ lid & leave to cool
2) Sterilise inoculating loop in the Bunsen burner flame
3) remove the plug & flame neck of culture tube
4) take a sample from the culture tube, & wipe on agar
5) tape the petri dish lid & incubate
How to check antibiotic efficacy
- pre soak paper discs in diff antibiotic solutions
- spread the bacteria on the surface of a sterile agar plate
- lightly press the paper discs into the surface & keep the agar plate in the incubator every night
Two more types of fermentation
Batch & continuous
What is batch fermentation
Micro-organisms are grown in batches in the fermentation vessel
Once the culture cycle is complete, the product is removed, the fermenter cleaned & new batch grown
- closed culture
What is continuous fermentation
Microorganisms are continually grown & products are harvested
Nutrients are added & waste is removed throughout the culturing
Factors to be controlled in batch & continuous fermentation & why
Batch versus continuous
N =
What are the 3 ways of measuring populations of micro-organisms
Direct counting
Viable counting
Turbidity
What’s direct counting
Samples of both living & dead cells to count individual micro-organisms
What’s viable counting
Living cells only: culture micro-organism samples to count the colonies that grow
What’s turbidity
Measure the living & dead micro-organisms by taking an absorbance reading using a colorimeter
-> it’s how cloudy the suspension is
Population growth curve of micro+organisms
Log scale benefit = allows for a wide range of values to be displayed
What’s happening in the lag phase
Length of phase depends on conditions
Reproduction slow as population acclimatises to space
What’s happening in the log phase
High availability of resources increasing & lots of space = exponential growth: low death rate, quick reproduction, no competition, lots of enzymes made
What happens in the stationary phase
Stationary = carrying capacity reached therefore population = max, as resources can’t support any more
Death rate = reproduction via binary fission
What happens in the death phase
Lack of nutrients & resources
Toxic substance build up, therefore death rate > reproduction rate
Factors affecting growth of micro-organisms
Temp
PH
Nutrient availability
Practical tips on how to count bacteria with agar
How to control each factor when checking microorganisms growth (pH,temp,nutrients)
What are immobilised enzymes
An enzyme attached to an insoluble material to prevent mixing with the product
Why are enzymes immobilised for use in industrial processes
Means it can be reused in future processes
How can enzymes be immobilised
Advantages of using immobilised enzymes
Disadvantages of using immobilised enzymes
Industrial applications of immobilised enzymes
Industrial applications of immobilised enzymes
