6.2.1 Cloning and Biotechnology COMPLETE Flashcards
1
Q
Clones
A
- Genetically identical copies
- Reproduces Asexually
- Mitosis creates two identical copies of DNA which is separated to form 2 genetically identical cells
- Clones are also formed in nature
2
Q
Examples of natural clones
A
- Identical twins
- Spider plant
- Bacteria
3
Q
Advantages of Natural Cloning
A
- Quick, reproduce rapidly
- Don’t need a mate
- If parent was well suited their offspring will be the same
4
Q
Disadvantages of Natural Cloning
A
- No genetic variety
- Equally vulnerable to disease
- High intraspecific competition
5
Q
Vegetative cloning
A
The production of structures in an organism that can grow into new individual organisms.
Offspring contain the same genetic information as the parent therefore clones
6
Q
Examples of Vegetive Cloning
A
Root suckers Tubers Bulbs Runners Rhizomes Corms
7
Q
Root suckers
A
New stems that grow from the roots from the meristem tissue close to the ground
e.g. Raspberry
8
Q
Tubers
A
Specialised underground stems become swollen with nutrients, forming tubers
e.g. Potato
9
Q
Bulbs
A
Condensed shoots with very short stems and fleshy leaf bases form, contain nutrients, buds at the sides develop into new bulbs
e.g. Onion
10
Q
Runners
A
Specialised stems grow along the ground from the parent plant, at the tips they form roots and shoots
e.g. Strawberries
11
Q
Rhizomes
A
A specialised horizontal stem running underground, often swollen with food. Buds develop and vertical shoots become independent plants.
e.g. Marram grass
12
Q
Corms
A
Often mistaken for bulbs, however sold rather than fleshy. It is an underground stem with scaly leaves and buds.
13
Q
Method: Cuttings
A
Produces large quantities of genetically identical plants quickly
- Cut stem between the leaf nodes
- Dip into rooting powder
- Place in damp soil
- Cover in plastic bag to prevent evaporation of water
14
Q
Method: Grafting
A
Used to ensure vigorous growth via selected rootstock. Can be used for new plants or to produce trees of different varieties
- Cut Scion from the desired plant
- Insert into the stem of rootstock, lining up vascular tissue
- Treat to prevent pathogens entering tissue
- Secure with tape
15
Q
Problems with taking cuttings and grafting
A
- Cant produce huge numbers or cloned plants easily or quickly
- Some plants are not suitable
- Takes up space
- May die
16
Q
Tissue Culture
A
- Growing new tissues, organs or plants from certain tissues cut from a plant
- The undifferentiated callus tissue is grown in nutrient rich medium containing plant hormones that stimulates development of the plant
17
Q
Advantages of Tissue Culture
A
- Very large quantities of genetically identical and disease free plants can be produced from one or very few parents, quickly
- Can be carried out at anytime of year, regardless of seasons
- Long term storage which can easily be modified
- Easier transport between countries as no need for quarantine
- Produce seeds of rare plants
18
Q
Steps involved in micropropagation
A
- A small piece of tissue taken from shoot tip, contains meristem cells
- Explants are sterilised using dilute bleach
- Placed on a nutrient rich medium containing ingredients for photosynthesis and hormones
- Cells divide but do not differentiate forming a mass of undifferentiated cells called a Callus
- After a few weeks its removed and placed on another growing medium for shoot and root growth. (contains hormones)
- The plantlets are then transferred to sterile compost and acclimatised in a greenhouse.
19
Q
Why are meristem cells used in micropropagation?
A
Free from viral infections
20
Q
What is inside the medium used in micropropagation?
A
Glucose, amino acids, phosphates for photosynthesis.
Auxin and Cytokinins to stimulate mitosis
21
Q
Why does micropropagation need to be carried out in sterile conditions?
A
The medium used for growth also provides the perfect growing conditions for the growth of bacteria
22
Q
Advantages of artificial cloning Plants
A
- Faster growing from seeds
- Reduce genetic variation to keep only useful features
- Some plants are unable to reproduce sexually
- Plants will be uniform in phenotype
- Uses apical bud which is free from infection
23
Q
Why is the meristem tissue free from viral infection?
A
- Not enough time to reproduce as the tissue is also regenerating
- No access to the vascular tissue
- High levels of auxin may inactivate the virus
24
Q
Disadvantages of Artificial cloning Plants
A
- Labour intensive
- Expensive to set up the facilities
- Can all fail if infected
- Genetic uniformity means all equally susceptible to new pests, diseases and environmental change
- No variation except mutation
25
Reproductive cloning of animals:
| 1. Embryo Splitting
1. Collect eggs from high value female
2. Collect sperm from high value male
3. In Vitro Fertilisation
4. Grow to a 16 cell embryo
5. Implant into surrogate mothers, each calf being a clone
26
Reproductive cloning of animals:
| 2. Somatic Cell Nuclear Transfer
1. A differentiated somatic cell from an adult is taken and the nucleus placed in an enucleated cell
2. Electrofusion takes place
3. The fertilised egg is implanted into a tied oviduct of a sheep to develop into an embryo
4. Embryo removed and placed into a surrogate
5. The resulting individual contains genetic information from the inserted nucleus
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Types of Reproductive cloning of animals
1. Embryo splitting
| 2. Somatic Cell Nuclear Transfer
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Non Reproductive cloning of animals
Production of genetically identical cells, not used to produce organisms
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Cloning for scientific research
The human cell line derived from cancer cells taken from Henrietta lacks who died in the 50s, without permission
The cells are immortal a grow when the divide
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Therapeutic Cloning
New tissues grown as a replacement, i.e. for skin grafts one burns
Cloned cells can help repair spinal chord of a mouse.
Potential to grow new organs
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Advantages of artificial cloning in animals
- High value animals can be mass cloned
- Rare animals can be cloned
- GM animals can be quickly reproduced
- Repair damage to donors
- Numbers of endangered species can be increased
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Disadvantages of artificial cloning in animals
- High value animals not reproduced with welfare in mind
- Uniformity in species makes it hard to adapt to change
- Unclear whether cloned animals remain healthy in long term
- Genetic diversity decreases
33
Using Stem Cells in non reproductive cloning
Hopefully can be used to treat diseases where cells stop working, i.e. diabetes
Difficult to obtain adult stem cells
Embryonic stem cells are totipotent so could theoretically be used to grow unless cells
34
Biotechnology
The use of living organisms or parts of living organisms in industrial processes, i.e. to produce food, drugs
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Why use Microbes
- Relatively cheap
- Rapid life cycles
- Prokaryotes reproduce asexually
- Proteins that are produced are easily harvested
- No ethical issues
- Genes are not found in pairs so its easy to genetically engineer
36
Applications of biotechnology
- Healthcare and medicine, produce drugs
- Agriculture, Genetically modify plants
- Industry, protease in washing powder
- Food science, golden rice
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Direct Food production- Single cell protein
Mycoprotein/ Quorn
Grown in large fermentors, then combined with albumen and compressed into meat substitutes.
High protein and low in fat
Waste can be used to make paper
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Advantages of using microorganisms to produce human food
- No animal welfare issues
- God source of protein
- No animal fat so lower cholesterol
- Faster production
- No seasonal variation in production
- Less land required
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Disadvantages of using microorganisms to produce human food
- May not want protein grown from waste
- Microbes need to be isolated from material grown
- Protein must be purified
- Biomass can contain high amounts of nucleic acids
- Doesn't have the same texture as traditional meat
- Flavour needs to be added
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Definition- Culture
A population of organisms grown under controlled conditions
| Nutrients are added to provide a better medium for microbial growth
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Definition-Closed Culture
Isolated from the external environment so no new material added, no waste removed, no organisms removed
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Ways to Measuring Growth of a culture
- Colorimeter
- Haemocytometer
- Viable counts
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Colorimeter
Measures the cloudiness/ turbidity
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Haemocytometer
Count the number of cells under the microscope in a known volume.
However some cels may be dead, may not be evenly distributed, hard to see
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Viable Counts
- Place known volume onto nutrient agar
- Incubate over night
- Count the colonies
- Use serial dilution otherwise there may be too many colonies that merge together making counting difficult
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Culture Growth- Lag phase
- Bacteria are active but not reproducing
- Adjusting to new conditions, i.e. synthesising enzymes for available nutrients
- Length depends on the conditions
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Culture Growth- Exponential/ Log phase
- Bacterial cells reproduce
- Plenty of nutrients and space
- Pop. doubles each generation
- Length depends on speed of reproduction, nutrients, O2 levels
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Culture Growth- Stationary phase
- Pop. levels stay the same (Death=Birth)
- Nutrient levels fall
- Waste (CO2) accumulates
- Possible lack of space
- -Reproduction eventually ceases
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Culture Growth- Decline phase
- Nutrient levels low
- Reproduction rate declines
- Toxic waste products and metabolites
- Death rate exceeds reproduction
- Eventually all organisms die in a closed system
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Indirect Food Production: Cheese Making
Bacteria feed on lactose in the milk which changes the taste and texture
Milk is pasteurised/ homogenised and mixed with chymosin enzyme and kept till it separates
Curd and whey is separated, then strained through draining moulds .
Left pressed, dried and left to mature
51
Indirect Food Production: Brewing
Yeast respires anaerobically to produce ethanol.
Malting involves barley germinating to produce the sugars needed by yeast
Mashing involves mixing the malt with warm water allowing enzymes to breakdown the starch and produce wort hops. (add flavour and antiseptic)
Fermentation is where wort and yeast are inoculated, temp is kept at optimum for aerobic respiration
Maturation is when beer is kept to condition
52
Indirect Food Production: Baking
Yeast is mixed with water and sugar to respire aerobically, the co2 bubbles help bread rise
After active yeast is added to other ingredients it rises with warm conditions.
Its then knocked back, kneaded and allowed to rise further before being baked
53
Indirect Food Production: Yoghurt Making
Uses both Lactobacillus bulgaricus and Streptococcus Thermophilus to produce yoghurt
Skimmed milk powder is added to to milk then pasteurised and homogenised, cooled at 47 degrees
Bacteria then added with a 1:1 ratio and incubated around 45 degrees.
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Advantages of using microorganisms to produce human food
- No animal welfare issues
- Good source of protein
- Faster production
- No seasonal variation
- Not as much land required
55
Disadvantages of using microorganisms to produce human food
- Protein must be purified
- Contamination could occur
- Not the same texture as meat
- Flavour needs adding
56
DEFINITION- Metabolism
All the chemical reactions taking place in an organism
| e.g. making new cells, chemicals, waste products
57
Primary metabolites
- Produced by an organism for growth
- Follow the line of population size
- Examples: Amino acids, nucleic acids, ethanol, enzymes
58
Secondary metabolites
- Substances produced that are not for growth but appear after the main growth period
- Line doesn't begin rising until stationary phase
- Examples: penicillin, destroys bacteria that inhibit growth
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Factors to consider when scaling up
- Mixing
- distribution of O2 and nutrients
- Overheating
- Contamination
- Cleaning
60
Conditions that need to be controlled in Industrial Fermentors
Temp- increases due to respiration, needs cooling to prevent denaturing enzymes
Nutrients available- Sources of carbon, nitrogen and minerals needed
O2 conc.- Needed for aerobic respiration
pH-Enzymes are affected by extremes in pH
Product conc.- If products build up it could affect the synthesis process
61
What is Batch Culture
Microorganism starter population is mixed with a specific quantity of sterile nutrient solution and allowed to grow for a fixed period with no nutrients added, at the end they're removed and the tank is emptied.
Examples: penicillin, beer
62
Aspects of Batch Cultures
- Growth rate is slower because nutrient levels decline
- Easy to set up and maintain
- If contamination occurs you only lose one batch
- Less efficient as not in operation all the time
- Useful to produce secondary metabolites, reach stationary phase
63
What is Continuous Culture
Sterile nutrients are added to fermentation tank and products removed at regular intervals/ continuously.
Process allows for pH levels, nutrients, and metabolic products to be kept constant
64
Aspects of Continuous Culture
- Growth rate is higher as nutrients are continuous;y added and it remains in the exponential phase
- Difficult to set up, maintenance required
- Lose huge volumes if contamination occurs
- More efficient
- Useful to produce primary metabolites
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Importance of Asepsis
If other microorganisms are present:
- Competitions for nutrients
- Reduced product yield
- Spoilt product
- Could create toxic chemicals
66
Asepsis Methods
- Sterilise with high temp, i.e. steam
- Use materials with smooth easy to clean surface
- Filter air
- Increase pressure so air flows out
- Wear lab clothes
67
Penicillin production
- Secondary metabolite so requires batch culture
- Only produced after a certain amount of penicillium is grown
- After exponential phase
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Production of Insulin
- Genetically modified bacteria
- Contian human insulin gene and can be grown on a large scale using continuous culture
- Downstream processing results in a constant supply of pure human insulin
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Bioremediation
Use of microbes to clean soil and underground water on polluted sites
Microbes convey toxic pollutants into less harmful ones
Can be in situ or ex situ
70
Advantages of Bioremediation
- Less labour needed
- Few waste products
- Uses natural systems
- Less risk of exposure to clean up personnel
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Immobilised enzymes
Enzymes can be attached onto an insoluble material so they can be reused
72
Advantages of Immobilised Whole Microbes
- Less expensive
- Cells produced the enzyme
- Cells may divide
- Do not need to replace the enzyme
- Useful if more than one step/enzyme involved
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Disadvantages of Immobilised Whole Microbes
- Microbes will use up the substrate growing on
- Unwanted reactions may occur, producing waste
- More downstream processing costs
74
Advantages of immobilised enzymes
- Enzymes are expensive
- Can be reused if immobilised
- Use in continuous fermentors
- Enzyme is protected from high temps and pH so less likely to denature
- Product isn't contaminated
- Less downstream processing costs
75
Disadvantages of immobilised enzymes
- More setting up costs so more expensive
- Reduced efficiency as enzymes can be less active
- Contamination can be very costly
76
Immobilising enzymes methods
Adsorption
Covalent bonding
Entrapment
Membrane seperation
77
Adsorption
Ionic bonds bind enzyme to solid support such as clay, enzymes adsorbed to the surface. Helps keep them stable but more leakage due to weaker bonds
78
Covalent Bonding (immobilising enzyme)
Enzymes are covalently bonded to the solid support, e.g. clay, using cross linking agent. Enzymes are strongly bound but may be costly
79
Entrapment
Enzymes are trapped inside beads, such as alginate beads. The active sites aren't affected but its difficult to entrap them.
80
Membrane Seperation
Enzymes separated physically from the substrate mixture by a partially permeable membrane. Enzymes are therefore kept separate but the diffusion of the substrate and product from the active site can be slow
81
Examples of immobilised enzymes in industry
Glucose Isomerase- Converts glucose to fructose for fit foods
Lactase- Converts Lactose to Glucose and Galactose for creating lactose free milk
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DEFINITION- Vegetative Propagation
The production of structures in an organism that can grow into new individual organisms
83
DEFINITION- Tissue Culture
Growing new tissues, organs or plants from certain tissues cut from a plant
84
DEFINITION- Explant
A small piece of tissue taken from a plant that contains meristematic cells
85
DEFINITION- Callus
Mass of undifferentiated cells
86
DEFINITION- Immobilisation
A process of confining enzyme molecule to a solid support over which a substrate is passed and converted over.
