6.4: Cloning and biotechnology Flashcards
What is vegetative propagation?
A form of asexual reproduction where new, genetically identical individuals develop from non-reproductive tissues of a parent plant such as its roots, stems, and leaves
What are the methods for vegetative propagation?
5x
Rhizomes
Stolons
Suckers
Tubers
Bulbs
How does the rhizomes method occur?
Specialised horizontal underground stems that store food and can produce new vertical shoots and roots from buds on nodes along the rhizome
What is an example of rhizomes?
Marram grass
How does the stolon method occur?
Horizontal stems that grow along the soil surface away from the parent plant, with nodes or stem tips that can root to form a new plant upon contact with the ground
What is an example of a stolon?
Strawberries
How does the sucker method occur?
Shoots that emerge from the shallow root buds of the parent plant
The original horizontal branch may die, leaving the new stem as a separate individual
What is an example of a sucker?
Elm trees
How does the tuber method occur?
Form when the tip of a stem becomes swollen with food, with buds on the tuber surface that can develop into new shoots.
What is an example of a tuber?
Potatoes
How does the bulb method occur?
Form when a leaf base becomes swollen with stored food, and the bud inside the bulb can form new shoots
How do you cut and grow cuttings?
6 steps
- Cut a 5-10 cm piece from the end of a parent plant’s stem using a sharp, sterile tool.
- Remove the lower leaves, leaving only one leaf at the top.
- Dip the cut end in rooting powder, which contains plant hormones that encourage root growth.
- Plant the cutting in a suitable growth medium, such as compost.
- Place it in warm, moist conditions to promote root development.
- Once rooted, transplant the new clone.
What is grafting?
Joining the shoot of one plant to the gorwing stem and root of another plant
Cut at an angle to increase surface area for adhesion
What are advantages of cloning?
- Cheap
- Quick growth compared to seeds
- Can clone seedless fruit
- Clones have a desired genetic makeup
What are disadvantages of cloning?
- Low genetic diversity/monoculture so less likelt to be able to adapt to changing selection pressures
What is micropropagation?
A technique for producing many identical plant clones from a single parent plant through a tissue culture.
It is a type of asexual reproduction on a very large scale
What are the five steps that micropropagation involves?
- Explant collection
- Sterilisation
- Culture
- Development
- Transfer
What does explant collection involve?
- Explants are typically taken from the stem and root tips as they have meristem cells
- Meristem cells are totipotent so can differentiate into any type of plant cell
Why does sterilisation occur?
- The explant’s cells are sterilised to remove and inhibit the growth of contaminants such as bacteria and fungi.
- This reduces the risk of widespread infection and helps to produce healthier crops.
What occurs in the culture step of micropropagation?
- The sterilised explant cells are then cultured on a nutrient-rich medium.
- The medium supplies minerals, sugars, vitamins, and growth hormones like auxins that support rapid cell division and growth.
What occurs in the development stage of micropropagation?
- The cells in each explant divide to form an undifferentiated mass of cells called a callus
- The callus cells are transferred to a new medium with specific conditions to encourage shoot and root formation
- This allows the callus cells to differentiate and develop into plantlets.
What occurs in the transfer stage of micropropagation?
- Fully formed plantlets, complete with shoots and roots, are moved to a growth medium like soil.
- There, they can develop into mature plants that are identical to the parent plant.
What are advantages of micropropagation?
- Produces plants that are genetically identical so there is a reliable inheritance of traits, such as those that produce high yields
- It can be carried out at all times of year
- It rapidly produces of a large number of mature plants.
What are disadvantages of micropropagation?
- All plants are genetically identical (monoculture) so crops are vulnerable to diseases and environmental changes
- It may unintentionally propagate undesirable traits
- It is expensive and requires skilled technicians, making it less feasible on a small scale
What is natural cloning in animals?
and examples
When animals produce genetically identical offspring using asexual reproduction
An early embryo splits into two genetically identical embryos
What is artificial embryo twinning?
4 steps
Animal with the desired trait is given hormone treatment to release more eggs
- A zygote is created by IVF
- The zygote is allowed to divide by mitosis to fomr a small ball of cells
- The cells are separated and allowed to continue dividing
- Each small mass of cells is placed into the uterus of a surrogate mother
What is somatic cell nuclear transfer?
6 steps
- An egg cell is obtained and its nucleus is removed, knonw as enucleation
- A normal body cell from the adult to be clones is isolated and may have the nucleus removed
- The complete adult somatic cell or its nucleus is fused with the empty egg cell by applying an electric shock
- The shock also triggers the egg cell to start developing as though it has just been fertilised
- Cell undergoes mitosis to produce a small ball of cells
- The young embryo is placed into the uterus of a surrogate mother
What is a use for artificial cloning?
Can be used for scientific research:
- Into the actions of genes that contorl development and differentiation
- Used to grow specific tissues or organs for use in tests on the effects of medicinal drugs
What are arguments for artifical cloning?
- Can produce a whole herd of animals with a high yield
- Produces a genetically identical copies of very high calue individuals retaining the same characteristics
- Individuals from an endangered species can be cloned to increase numbers
What are arguments against artificial cloning?
- Lack of genetic variation may expose the herd to certain diseases or pests
- Success rate of adult cell cloning is bery poor and the method is a lot more expensive than conventional breeding
- Does not help increase genetic diversity
What is biotechnology?
Large scale/commercial use of living organisms for human consumption to produce food, drugs and other products
What are the four major applications of biotechnology that effects our lives?
- Healthcare and medical processes
- Agriculture
- Industry
- Food science
Food production is a purpose of biotechnological processes. What is an example and organisms involved?
Example:
- Cheese making
- Quorn aka mycoproteins
Organisms involved:
- Lactobacillus bacteria
- Fusarium venenattum fungus
Drugs and pharmeceutical chemical production is a purpose of biotechnological processes. What is an example and organisms involved?
Example:
- Penicillin production
- Insulin production
Organisms involved:
- Penicillin (fungus)
- E. Coli
Production of enzymes and chemicals for commercial use is a purpose of biotechnological processes. What is an example and organisms involved?
Examples:
- Peclinase - used to extract juice from fruit
- Protease and lipase - in washing powders
Organisms involved:
- Aspergillus niger
- Bacteria
Bioremediation is a purpose of biotechnological processes. What is an example and organisms involved?
Examples:
- Removal of waste products e.g oil spills
Organisms involved:
- Various bacteria and fungi break down the waste products into less harmful substances
Why are microorganisms used in biotechnology?
- Cheap and easy to grow
- Production process takes place at a lower temperature than would be requied to make the molecules by chemical engineering - saves fuel and reduces costs
- Short life cycle and reproduce quickly
- Fewer ethical considerations to worry about
How is yoghurt produced?
4 steps
- Milk undergoes fermentation by lacotbacillus bulgarius and streptococcus thermaphilis
- Bacteria convert lactose to lactic acids
- The acidity denatures the milk protein causing it to coagulate
- The bacteria partially digest the milk -> easy to digest
How is cheese produced?
5 steps
- Milk is pretreated with a culture of bacteria lactobaccilus
- Once acidified it is mixed with rennet which coagulates the milk protein (caesin) in the presence of Ca2+
- Curd is separated from liquid component by cutting, stirring and heating
- The bacteria continue to grow producing more lactic acids
- Curd is then pressed into moulds
What are advantages of using microoganisms?
3x
- Production of protein can be many times faster than that of animal or plant protein
- Production can be increased or decreased according to demand
- No animal welfare issues
What are disadvantages of biotechnology?
3x
- Growth conditions are also ideal for contaminating microorganisms so aseptic techniques are used
- People may not want to eat fungal protein or food that has been grown on waste
- The protein has to be purified to ensure it is uncontaminated
What is a fermentor/bioreacter and why are they used?
Sealed sterile, aeseptic units so that the product is not contaminated and the microorganisms are not in competition with other organisms
Used for culturing microorganisms in industry
What are limiting factors for growth of bacterial colonies?
- Temperature
- Nutrients available
- Oxygen levels
- Change in pH
- Build up of waste
Why is temperature a limiting factor in culturing microorganisms?
Need to maintain the optimum temperature for enzyme controlled reactions such as aerobic respiration
Why is the amount of nutrients available a limiting factor in culturing microorganisms?
Microoganisms require nutrients to grow and synthesise the product
Source of of carbon, nitrogen, minerals and vitaminds are needed
Why is oxygen levels a limiting factor in culturing microorganisms?
Needed for aerobic respiration
Why is change in pH a limiting factor in culturing microorganisms?
This will fall as carbon dioxide produced - this will impact on enzymes involved in metabolic processes such as respiration therefore a pH buffer is used
Why is build up of waste a limiting factor in culturing microorganisms?
As bacterial numbers rise, anaerobic respiration may occur which can lead to the build up of ethanol/lactic acid which can kill the microorganisms
What is batch fermentation?
- Microorganism are grown in batches in the fermentation vessel
- Closed culture
- Once the culture cycle is complete product is removed, fermenter is closed and new batch of microorganism grown
What is continuous fermentation?
- Microorganisms continuously grown and the products harvested
- Nutrients are added and wasted and removed throughout the culturing process
What are primary metabolites?
Products made by microorganisms during normal metabolism continually released from cell
Broth topped with nutrients
- Insulin production for type 1 diabetes
Continuous fermentation
What are secondary metabolites?
Products produced when microoganisms are under stress
E.g high population density
Only produced once population size reaches a certain size
- Pennicillin
What is the importance of asepsis?
The unwanted microorganisms:
- Compete with the cultured microorganisms for nutrients and space
- Reduce the yield of useful products
- Produce toxic chemicals
What is the production of penicillin?
4 steps
- The fermenter is run for six to eight days
- The culture is then filtered to remove the cells
- The antibiotics is precipitated as crystals by the addition of potassium compounds. The antibiotic may be modified by the potassium action of other microorganisms or by chemical means
- The antibiotic is mixed with inert substances and prepared for administration
What is the production of insulin?
2 steps
- Gene for human insulin was combined with a plasmid to act as a vector
- So the gene could be inserted into E. Coli
What is bioremediation?
Use of microorganisms to clean the soil and underground water on polluted site
The organisms convert toxic pollutants to less harmful substances
What are the right conditions for the growth of microorganisms in bioremediation?
- Available water
- A suitble temperature
- Suitable pH
What are advantages of bioremediation?
5 things
- Uses natural systems
- Less labour/equipment is required
- Treatment in situ
- Few waste products
- Less risk of exposure to clean up personnel
What is a disadvantage of bioremediation?
Only suitable for certain products; heavy metals such as cadmium and lead cannot be treated
What is the procedure of aseptic techniques?
6x
- Wash your hands
- Disinfect the working area
- Have a bunsen burner operating nearby to heat the air - allowa sterile air
- Pass neck of bottle over the flame to prevent bacteria in the air entering the bottle
- Do not lift the lid of perti dish completely
- Any metal equipment or glassware should be passed through flame before and after contact with microorganisms
What is a growth curve?
Shows the growth of a population of microorgansims in a closed culture
What are the stages of the growth curve?
4x
- Lag phase
- Log (exponential phase)
- Stationary phase
- Death (decline) phase
What happens in the lag phase?
Population does not grow quickly because it is still small and because organsims are adjusting to their new environment
Involves:
- Taking up water
- Cell growth
- Switching on (activating) certain genes
- Synthesising specific proteins (enzymes)
What happens in the log (exponential) phase?
- Organisms have adjusted to their environment
- Have enzymes needed to survive
- Sufficient nutrients and space to grow rapidly and reproduce
- Population doubles in size wiht every generation
primary metabolites are collected from a fermenter
What happens in stationary phase?
- Increasing numbers of organsisms use up the nutrients and produce increasing amounts of waste products such as CO2 and other metabolites
- Rate of population growth declinesand the number of individuals dying increases until the reproduction rate equals the death rate
secondary metabolites are produced
What happens in the decline (death) phase?
- Nutrients run out and concentration of waste becomes lethal
- More individuals die than be produced
- All organisms die
