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Biology > Genetics- Cloning and Biotechnology > Flashcards

Genetics- Cloning and Biotechnology Flashcards

1
Q

How do many flowering plants clone?

A

Vegetative propagation, where a structure forms which develops into a fully differentiated new plant.
New plant is genetically identical to the parent

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2
Q

Where may a new plant be propagated from?

A

Stem, leaf, bud or root of the parent, depending on the type of plant

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3
Q

How does natural plant cloning occur in bulbs?

A

Leaf bases swell with stored food from photosynthesis. Buds form internally which develop into new shoots and new plants in the growing season

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4
Q

How does natural plant cloning occur through runners?

A

A lateral stem grows away from the parent plant and roots develop where the runner touches the ground. A new plant develops and the runner withers away, leaving the new individual independent

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5
Q

How does natural plant cloning occur through rhizomes?

A

Rhizome is a specialised horizontal stem running underground, often swollen with stored food. Buds develop and form new vertical shoots which become independent plants

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6
Q

How does natural plant cloning occur through stem tumbers?

A

Tip of an underground stem becomes swollen with stored food to form a tuber or storage organ. Buds on the storage organ develop to produce new shoots

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7
Q

How can a plant cutting be taken and used to grow a clone plant?

A

1) Use a non-flowering stem
2) Cut stem at an angle to increase surface area
3) Apply hormone rooting powder (auxins) to cut stem to encourage root growth
4) Plant cutting into soil and keep it well watered
5) Cover the cutting with a plastic bag for a few days to prevent water loss, until its roots have developed more

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8
Q

What is micropropogation?

A

Process of making large numbers of genetically identical offspring from a single parent plant using tissue culture

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9
Q

When is micropropagation used?

A

When a desirable plant:

  • Does not readily produce seeds
  • Doesn’t respond well to natural cloning
  • Is very rare
  • Has been genetically modified
  • Is required to be ‘pathogen free’ by growers
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10
Q

What is the method for micropropagation?

A

1) Take a small sample of meristem tissue from shoot or root tips of plant under aseptic technique to avoid contamination (fungi/bacteria)
2) Sample is sterilised in bleach or ethanol
3) Explant placed in sterile culture medium, containing a balance of plant hormones and nutrients
4) Cells proliferate, forming a mass of identical cells called a callus
5) Callus divided up and transferred to a new culture medium containing a different mixture of hormones and nutrients, which stimulates the growth of genetically identical plantlets
6) Plantlets plotted into compost where they grow into young plants
7) Young plants planted out to grow and produce a crop

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11
Q

What are the advantages of micropropagation?

A
  • Allows for rapid production of large numbers of plants with known genetic make up which will yield good crops
  • Produces disease free plants
  • Makes it possible to produce viable number of plants after genetic modification
  • Produce large number of seedless plants, good to meet consumers tastes
  • Provides a way for growing plants which are naturally relatively infertile or difficult to grow from a seed
  • Reliably increase numbers of rare or endangered species
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12
Q

What are the disadvantages of micropropagation?

A
  • Produces a monoculture, so they are all susceptible to same diseases or changes in growing conditions
  • Relatively expensive
  • Requires skilled workers
  • If source material is infected with a virus, all clones will also be infected
  • In some cases, large number of new plants are lost during the process
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13
Q

What type of animal is natural cloning common in?

A

Common in invertebrate animals. Although it is less common in vertebrates, it still occurs in the form of twinning

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14
Q

How does cloning in invertebrates occur?

A
  • Can take several forms
  • Some animals can regenerate entire animals from fragments of the original if they are damaged (starfish)
  • Flatworms and sponges fragment and form new identical animals as part of their normal reproductive process
  • Hydra produce small buds on their body which develop into genetically identical clones
  • Some female insects can produce offspring without mating, however they are not true clones
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15
Q

How does cloning in vertebrates occur?

A
  • Main form of cloning is in the form of monozygotic twins (indetical)
  • The early embryo splits to form two separate embryos
  • Frequency in which twins occur varies between species
  • When monozygotic twins are born, they may look different as a result of different in their position and nutrition in the uterus, however are still genetically identical
  • Some female amphibians and reptiles will produce offspring when no male is available
  • All of genetical material arises from her, but offspring are often male so no true clones
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16
Q

What are the two forms of artificial cloning in vertebrate animals?

A

1) Artificial twinning

2) Somatic cell nuclear transfer

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17
Q

What is artificial twinning?

A

The split in the early embryo is produce manually. It may be split in half or more to produce a certain number of genetically identical offspring. It is widely used in by the farming community to produce maximum offspring from desirable cattle or sheep

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18
Q

What are the stages of artificial twinning?

A

1) Female animal with desirable traits is treated with hormones so she super-ovulates, releasing more mature ova than normal
2) Ova may be fertilised naturally or by AI by a male with particularly good traits
3) Early embryos are gently flushed out of the uterus
4) Or mature eggs are removed and fertilised by AI in the lab
5) While cells are still totipotent, cells of early embryo are split to produce several, smaller embryos (all capable of growing to full-term)
6) Each of split embryo grown in lab for a few days and then implanted into a surrogate mother
7) Each embryo implanted into a different mother as single pregnancies carry less risk
8) Embryos develop into foetuses and are born normally
9) Embryos produced are genetically identical to each other

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19
Q

What is somatic cell nuclear transfer?

A

Cloning of an adult animal by taking the nucleus from an adult somatic cell and transferring it into an enucleated egg cell (nucleus removed), which is then used to produce an embryo that is a clone of the original adult

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20
Q

What is the process for somatic cell nuclear transfer?

A

1) Nucleus removed from somatic cell of an adult animal
2) Nucleus removed from a mature ovum harvested from a different female animal of the same species
3) Nucleus from adult somatic cell placed into enucleated ovum and given a mild electric shock so it fuses and begins to divide
4) The embryo that develops is transferred into the uterus of a third animal (surrogate mother), where it develops to term
5) The new animal is a clone of the animal from which the original somatic cell is derived, although the mitochondrial DNA will come from the egg cell

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21
Q

What are the arguments for animal cloning?

A
  • Animal twinning enables high yielding farm animals to produce many more offspring than normal reproduction
  • Artificial twinning enables the success of a male animals passing on desirable genes to be determined
  • SCNT enables GM embryos to be replicated and developed, which is important in pharming
  • SCNT enables scientists to clone specific animals to replace specific pets or cloning top class race horses
  • SCNT has the potential to enable rare, endangered, or even exist animals to be reproduced
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22
Q

What are the arguments against animal cloning?

A
  • SCNT is a very inefficient process, in most animals it takes many eggs to produce a single cloned offspring
  • Many cloned animal embryos fail to develop and miscarry or produce malformed offspring
  • Many animals produced by cloning have shortened life spans or premature ageing
  • SCNT has been relatively unsuccessful so far in increasing the populations of rare organisms or allowing extinct species to be brought back to life
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23
Q

What is biotechnology?

A

The use of living systems and organisms to develop or make useful products

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24
Q

Why are microorganisms used in biotechnology?

A
  • No welfare issues to consider
  • Enormous range of microorganisms capable of carrying out many different chemical syntheses
  • Genetic engineering allows us to artificially manipulate microorganisms to carry out synthesis reactions that they would not do naturally (human insulin)
  • Microorganisms have a very short life cycle and rapid growth rate
  • Nutrients required of microorganisms are often very simple and relatively cheap
  • Conditions at which most microorganisms need to grow include a relatively low temperatures and pressures as they provide their own catalysts so these processes are cheaper
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25
Q

What processes are microorganisms used in?

A
  • Baking
  • Brewing
  • Cheese making
  • Yoghurt making
  • Insulin production
  • Penicillin production
26
Q

How are microorganisms used to produce penicillin?

A
  • Fungi used not the original fungi that it was discovered from as it actually has a relatively low yield
  • Fungi needs relatively high oxygen levels and a rich nutrient medium to grow well
  • Semi continuous batch process is used
  • In first stage of production process the fungus grows
  • In the second stage it produces penicillin
  • Then, the drug is extracted and purified
  • Mixture continuously stirred to keep it oxygenated
  • Mixture contains a buffer to maintain pH
  • Maintain around room temperature
27
Q

What are the advantages of using microorganisms to produce human food?

A
  • Microorganisms reproduce fast and produce protein faster than animals and plants
  • Microorganisms have a high protein content with little fat
  • Microorganisms can use a variety of waste materials, including human and animal waste, which reduces costs
  • Microorganisms can be genetically modified to produce protein required
  • Production of microorganisms is not dependent on weather, breeding cycles, etc.
  • Can be increase or decreased to match demand
  • No welfare issues
  • Can be made to taste like anything
28
Q

What are the disadvantages of using microorganisms to produce human food?

A
  • Some microorganisms can also produce toxins if the conditions are not maintained at the optimum
  • The microorganisms have to be separated from the nutrient broth and processes to make the food
  • Need sterile conditions that are carefully controlled which increases costs
  • Often involved GM organisms and many people have concerns about eating GM food
  • Protein has to be purified to ensure it contains no toxin or contaminants
  • Has little natural flavour and requires additives
29
Q

What is bioremediation?

A

Microorganisms are used to break down pollutants and contaminants in the soil or in water

30
Q

What are the two approaches to bioremediation?

A

1) Using natural organisms
2) Using GM organisms
- develop GM bacteria that breakdown or accumulate contaminants that they wouldn’t usually encounter
- use bacteria to develop filters to help clean up polluted areas

31
Q

How are microorganisms cultured?

A
  • Inoculated onto a nutrient medium which can either be liquid (broth) or solid (agar)
  • Nutrient medium must be kept sterile so aseptic technique is carried out
32
Q

How to inoculate bacteria into broth?

A

1) Make a suspension of the bacteria to be grown
2) Mix a known volume with sterile nutrient broth in the flask
3) Stopper the flask with cotton wool to prevent contamination from airborne pathogens
4) Incubate at a suitable temperature, shaking regularly to aerate the broth, providing oxygen for the growing bacteria

33
Q

How to inoculate bacteria onto agar?

A

1) Wire inoculating loop must be sterilised by dipping in ethanol then holding it in a bunsen burner until it glows red hot
2) Dip sterilised loop in the bacteria suspension, remove the lid of the Petri dish and make a zig-zag streak across the surface of the agar.
- Avoid the loop digging into the agar by holding it almost horizontal
3) Replace lid of Petri dish and hold it down with tape. Don’t seal completely otherwise bacteria won’t be able to aerobically respire
4) Incubate at a suitable temperature

34
Q

What are the four stages of the bacterial growth curve?

A

1) Lag phase
2) Log or exponential phase
3) Stationary phase
4) Decline or death phase

35
Q

What is the lag phase?

A
  • Bacteria are adapting to their new environment
  • Binary fission rate=Death rate
  • They are growing, synthesising the enzymes they need and not yet growing at their maximum rate
36
Q

What is the log or exponential phase?

A
  • When the rate of binary fission is greater than the death rate
  • Bacteria are in optimum growth conditions, with plenty of nutrients, oxygen and space
37
Q

What is the stationary phase?

A
  • Binary fission rate=death rate
  • Increase in metabolic waste
  • Space and nutrients all used up
  • Not ideal conditions for bacteria to grow
38
Q

What is the decline or death phase?

A
  • Death rate is greater than binary fission rate

- Population decreases

39
Q

What limiting factors prevent exponential growth in a culture of bacteria?

A
  • Nutrients available
  • Oxygen levels
  • Temperature
  • Build up of waste (toxic material)
  • Change in pH
  • Space
40
Q

What is a primary metabolite?

A

Metabolite released as a result of metabolic processes which are essential for the life of the microbe. Produced especially during the exponential growth phase

41
Q

What is a secondary metabolite?

A

Metabolite produced that is not essential for life and not produced as a result of growth of the microbe. Produced after exponential growth phase so cannot be produced in continuous fermenters. Penicillin is a secondary metabolite

42
Q

What is batch fermentation?

A
  • Microorganisms are inoculated into a fixed volume
  • As growth takes place, nutrients are used up and both new biomass and waste products build up
  • As culture reaches stationary phase, overall growth ceases but during this phase, microorganisms often carry out biochemical changes to form the desired end products
  • Process is stopped before death phase and products harvested
  • Whole system is cleaned and sterilised and a new batch culture is started up
43
Q

What is continuous fermentation?

A
  • Microorganisms inoculated into sterile nutrient medium and start to grow
  • Sterile nutrient medium is added continuously to the culture once it reaches the exponential point of growth
  • Culture broth is continually removed at the end of the exponential growth phase, right before the stationary phase
44
Q

What are the differences between batch and continuous fermentation?

A
  • Continuous creates a higher yield than batch
  • Levels of nutrients and pH more or less constant in continuous
  • Quality varies in batch fermentation, whereas its more consistent in continuous
  • No limiting factors in continuous so faster growth rates
  • Smaller vessel used for continuous
  • Batch easier to set up and maintain
  • Batch less efficient as more time wasted shutting down and removing the product
  • Contamination more severe in continuous as all product produced will have gone to waste whereas batch only affects one lot of product
45
Q

Why are immobilised enzymes used?

A

Prevent enzymes from being lost in the reaction mixture

46
Q

How can enzymes be isolated?

A

1) Adsorbed onto inorganic carriers (silica, cellulose)
2) Covalently or ionically bonded to inorganic carriers (carriers with amino/hydroxyl groups or polysaccharides such as cellulose)
3) Entrapment within a matrix (gelatin, polysaccharides)
4) Membrane entrapment in microcapsules or behind a semi-permeable membrane (polymer-based)

47
Q

What are some examples of immobilised enzymes?

A
  • Penicillin acylase
  • Glucose isomerase
  • Lactase
48
Q

What is penicillin acylase used for?

A
  • Used to make semi synthetic penicillins from naturally produced penicillins which is used to kill bacteria that is resistant to regular penicillin
  • Are very important in treating bacterial infections in patients, where the bacteria is penicillin resistant
49
Q

What is glucose isomerase used for?

A
  • Used to produce fructose from glucose

- Fructose is much sweeter and is used in the food industry

50
Q

What is lactase used for?

A
  • Used to produce lactose free milk

- Hydrolyses lactose to glucose and galactose, which makes up lactose free milk

51
Q

What are the advantages of using isolated enzymes?

A

1) Only one enzyme is present so there will be no wasteful side reactions
2) Easier to isolate and purify desired product
3) Only one chemical process needs to be considered- easier to set up optimum conditions

52
Q

What are the advantages of using immobilised enzymes?

A
  • Can be reused, which is cheaper
  • Easily separated from reactants and products they are catalysing, so reduced downstream processing (cheaper)
  • More reliable as surface provides a stable microenvironment
  • Greater temperature and pH tolerance
  • Easy to manipulate catalytic properties to fit a particular process
53
Q

What are the disadvantages of using immobilised enzymes?

A
  • Reduce efficiency, process of immobilising an enzyme may reduce its activity rate
  • High initial cost of materials, immobilised enzymes are more expensive than free enzymes or microorganisms, however do not need to be replaced as often
  • Higher initial costs of bioreactor, system needed to use immobilised enzymes is different from traditional fermenters so there is an initial investment cost
  • More technical issues, reactors that use immobilised enzymes are more complex than simple fermenters, so they have more things that can go wrong
54
Q

How does fermenting contribute to the production of human insulin?

A

Genetically engineered bacteria that contain gene for human insulin are grown in a fermenter and downstream processing results in a constant supply of human insulin

55
Q

How can serial dilution be used to count the number of microorganisms in an investigation?

A
  • When you culture a given volume of the broth on the agar plate, you can count the number of colonies
  • Multiply the number of colonies by the dilution factor to give you a viable cell count per volume of the original colony
  • As long as you can count the number of colonies on two or more plates, you can calculate the mean of the number of organisms in a particular culture
56
Q

How can bacteria cell numbers be counted?

A

1) Direct cell counts
- Counting chambers
- Electronic counters
- On membrane filters
2) Viable cell counts
- Plating methods
- Membrane filtration methods

57
Q

How can counting chambers be used to measure microbial growth?

A
  • Specific volume of a bacterial suspension placed on a microscope slide with a special grid
  • Stain is added to visualise bacteria
  • Cells are counted and multiplied by a factor to obtain concentration
58
Q

What are the advantages of using counting chambers to measure microbial growth?

A
  • No incubation time required

- Relatively easy to carry out

59
Q

What are the disadvantages of using counting chambers to measure microbial growth?

A
  • Cannot always distinguish between live and dead bacteria
  • Motile bacteria are difficult to count
  • Requires a high concentration of bacteria
60
Q

What is the indirect method to measure microbial growth?

A
  • Inoculated broth placed in colorimeter
  • Amount of light allowed to pass is detected by a photocell receptor
  • More turbid broth culture will have a greater population
  • Mass of nutrients and waste then measure to show level of metabolic activity
  • Then dry mass, where organisms are filtered from culture, dried and measured

Biology (33 decks)

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