Cloning and biotechnology 6.4 Flashcards
1
Q
What are clones?
A
Genetically identical organisms or cells
2
Q
How are clones produced naturally?
A
Asexual reproduction (mitosis)
3
Q
What are the advantages of natural cloning?
A
- if the conditions for growth are good for the parent , they will also be good for the offspring
- cloning is relatively rapid (population can increase quickly)
- reproduction can be carried out even if there is only one parent
4
Q
What are the disadvantages of natural cloning?
A
- offspring may become overcrowded
- no genetic diversity (appart from random mutations)
- population shows little variation
- selection is not possible
- if the environment changes to be less advantageous, the whole population is susceptible
5
Q
What is vegetative propagation?
A
The process of reproduction through vegetative parts of the plant rather than specialised reproductive structures
6
Q
What are the types of vegetative propagation?
A
- root suckers
- tubers
- bulbs
- runners/ rhizomes
- corms
- leaves
7
Q
Describe what type of vegetative propagation root suckers are and give an example?
A
- they are new stems growing from the roots
- original branch may die to create an new plant
Eg/ english elm or raspberry
8
Q
Describe what type of vegetative propagation tubers are and give an example?
A
- undergroound stem produced by plants where the tuber forms an ‘eye’ from which new plant will grow
Eg/ potato
9
Q
Describe what type of vegetative propagation bulbs are and give an example?
A
- underground stem will grow a series of fleshy leaf bases and an apical bud wich grows into a new plant in spring
- some have multiple apical buds which each grow into a new plant
Eg/ onions
10
Q
Describe what type of vegetative propagation runners/ rhizomes are and give an example?
A
- horizontal stems that grwo on the surface and can form roots (runners)
- horizontal stems that grow underground (rhizomes)
- stems eventually breakdown to form new plant
Eg/ strawberry
11
Q
Describe what type of vegetative propagation corms are and give an example?
A
- underground stems with scaly leaves and buds from which buds grow to produce several new plants
Eg/ croci and gladioli
12
Q
Describe what type of vegetative propagation leaves are and give an example?
A
- they are clones which can grow along leaf margins which drop off and forms roots into the soil
- kalanchoe
13
Q
How do you take plant cuttings?
A
- cut a stem between two leaf joints (nodes)
- dip the cut stem in rooting hormone to stimulate root growth
- place the cut end of the stem in moist soil
- new roots will grow from the tissue
(can also be done using root, leaf and scion cuttings)
14
Q
How are artificial plant clones created uring micropropagation and tissue culture?
A
- it involves taking an explant and using plant growth substances to encourage it to grow and develop into a new plant
- suitable plant is collected and cut into small pieces (explant), could be leaf, stem, root or bud
- explants sterilised using dilute bleach to kill bacteria and fungi
- explants placed on a sterile growth medium (agar gel) containing nutrients, auxin and cytokinins to stimulate the cells to divide by mitosis to form a callus (mass of undifferenciated totipotent cells)
- once calus is formed it is split into small clumps
- small clumps are stimulated to grow and differentiate
- once tiny plantlets have been formed they are transferred to a greenhouse to grow in soil and acclimatise to normal growing conditions
15
Q
What are the advantages of artificial cloning in plants?
A
- Cloning is a fast method of producing new plants
- cloning can be carried out where sexual reproduction is not possible
- plants selected will be genetically identical to the parent plant so will display the desireable characteristics
- unusual combinations of characteristics can be retained
- new plants are all uniform in their pheotype so are easier to grow and harvest
- using the apical bud as an explant ensures new plant os free from diseases
16
Q
What are the disadvantages of artificial cloning in plants?
A
- tissue culture is labour intensive
- expensive to set up facilities to perform tissue culture successfully
- tissue culture can fail due to microbial contamination
- no genetic variation (par mutation)
- offspring is genetically identical so susceptible to the same pests & diseases (monoculture)
17
Q
What is a form of natural clones in animals?
A
Identical twins formed by embryo splitting
18
Q
What type of cells are needed for cloning?
A
Totipotent
19
Q
What are te two techniques for reproductive cloning?
A
- embryo splitting
- somatic cell nuclear transfer (SCNT)
20
Q
What is the process of embryo splitting?
A
- zygote (fertilised egg) is created by IVF
- zygote is allowe to divide by mitosis to form a ball of cells
- the cells are separated and continue dividing
- each mass of small cells is placed into the uterus of a surrogate mother
- they then give birth to genetically identical offspring
21
Q
What is the process of somatic cell nuclear transfer (SCNT)?
A
- egg cell is obtained and its nucleus is removed (enucleation)
- a somatic cell from the adult to be cloned is isolated and enucleated
- the nucleus from the somatic cell is fused with the empty egg cell by applying an electric shock (electro-fusion)
- triggers the egg to start developing as if it has been fertilised
- cell undergoes mitosisto produce aa ball of cells
- young embryo is placed into the uterus of the surrogate mother
- they give birth to offspring which is genetically identical to the somatic cell donor
22
Q
What is a form of non-reproductive cloning?
A
Theraputic cloning
23
Q
How does theraputic cloning work?
A
- new tissue and organs grown as replacement parts
- skin can be grown in vitro to act as a grapht over burns
- cloned cells repair damage to the spinal cord of a mouse and restorred its ability to produce insulin
- potential to grow whole new organs to replace diseased organs
24
Q
What are the arguments for artificial cloning of animals?
A
- can produce a whole herd of animals with aa high yield
- produces genetically identical copies of high value individuals
- genetically identical tissues for sceintific research allows the effects of genes and hormones to be assessed
- testing medicenal drugs on cloned cells avoids using animals
- can produce cells genetically identical to the donor to reapir damage
- individuals from endangered species can be cloned to increase numbers
25
What sre the arguments against artificial cloning of animals?
- does not help increase genetic diversity
- lack of genetic variation exposes herds to diseases or pests
- animals may be prduced with little regard to their welfare such as meat producing chickens which cannot walk
- success rate of adult cell cloning is very poor and expensive
- cloned animals may have a shorte life span and are less healthy
- ethical issues regarding how long the embryo survives and whether it is rght to create a life to destroy it
26
What are the 4 main areas in which microoganisms are used in biotechnology?
- food
- pharmaceutical drugs
- enzymes
- othe products
27
What are examplels of microoganisms being used in food?
- ethanol in beer and wine (yeast)
- CO2 to make bread rise (yeast)
- lactic acid to make cheese and yoghurt (bacteria)
- mycoprotein for vegetarian food (fungus)
28
What are examplels of microoganisms being used in pharmaceutical drugs?
- penicillin (fungus)
- antibiotics (fungi and bacteria)
- insulin (GM bacteria)
29
What are examplels of microoganisms being used in enzymes?
- protease and lipase in washing powder (bacteria)
- sucrase to digest sugar for food sweetener (yest)
- protease to tenderise meat (aspergilus spp)
- lactase to make lactos free milk (A.niger)
30
What are examplels of microoganisms being used in other products?
- citric acid, E330, a food preservative (fungus)
- bioremediation to clean waste water (bacteria & fungi)
31
What are the advantages of using microorganisms in biotechnology?
- cheap and easy to grow
- production process takes place at a lower temperature which saves fule and reduces costs
- production process takes place at normal atmospheric pressure which is safer
- production process is not dependent on climate, can happen anywhere in the world
- microorganisms can be fed by products from other food industries
- short life cycle and reproduce quickly inside reaction vessel (fermenter)
- microorganisms can be GM relatively easily
- fewer ethical concerns
- product is often more pure and easier to isolate
32
What are the two types of growth mediums?
- liquid broth kept in bottles
- agar poured into petri dishes
33
What are the standard procedures for aseptic techniques?
- wash your hands
- disinfect working area
- have bunsen burner operating nearby to create an area of sterile air and to prevent air-born microorganisms
- when opening the vessel pass the neck of the bottle over the flame to prevent bacteria in air entering the bottle
- do not lift the lid of the petri dish completely
- pass any glassware or metal equipment through the flame before and after contact with desired microorganisms
34
What are the three main steps to growing microorganisms on agar plates?
- sterilisation
- inoculation
- incubation
35
What is the process of sterlisation?
- agar medium and equipment must be sterilised
- medium is heated in an autoclave at 121C for 15 min
- it is poured into a sterile petri dish and left to set
- place lid on petri dish to prevent infection
- all equipment must be sterilised by heating
36
What is the process of inoculation?
- it is the introduction of microorganism to the sterile medium
- streaking - wire inoculating loop is used to transfer a drop of liquid medium onto the surface and is drawn out into a streak by dragging the loop across the surface
- seeding - sterile pipette used to transfer a small drop of liquid medium to the surface of the petri dish before the agar is poured in
- spreading - sterile glass spreader can be used to spread the inoculated drop over the surface of the agar
37
What is the process of incubation?
- petri dish is labelled and taped (not sealing it completely)
- it is placed in a suitable warm environment such as an incubator
- should be placed upside down to prevent condensation on the agar
- culture can be examined after 24-36 hours
38
What happens in a liquid medium to indicate bacterial growth?
The broth turns cloudy
39
What is serial dilution and what is the process?
- it is a step wise dilution of the broth cculture where at each step the culture is diluted by a factor of 10
- take a 1cm sample from the broth and add 9cm of distilled water (lable as 10^-1)
- take a 1cm sample from this diluted broth and add 9cm of distilled water (lable as 10^-2)
- continue until you have a series of dilutions
- a drop of each dilution can be used to inoculate an agar plate where one of them wil produce a culture in which you can count the individual colonies
- when recording the population density multiply your count by the dilution factor and by the volue added
40
What is the growth curve?
It is the predictable pattern that the population growth of microoganisms in a closed culture containg all the nutrients required for growth will follow
41
What are the phases of the growth curve?
- lag phase
- exponential phase
- stationary phase
- death/decline phase
42
What happens during the lag phase?
- population does not grow quickly due to adjusting to their new environment and small population size
- take up water
- cell growth
- activating genes
- synthesising specific proteins (enzymes)
43
What happens during the exponential phase?
- organisms have adjusted to their environment
- enough nutrients and space to grow rapidly
- population doubles in size with each generation
44
What happens during the stationary phase?
- increasing number of organisms use up the nutrients
- produce increasing amounts of waste products (CO2 and metabolites)
- rate of populationg growth declines
- number of individuals dying increases
- reproduction rate equals death rate
- no population growth
45
What happens during the death/decline phase?
- nutrients run out
- conc. of waste products becomes lethal
- rate of death is higher than rate of reproduction
- all organisms will die
- population decreases
46
What are primary metabolites?
Produced during the normal activities of the microorganisms and are collected from a fermenter during the exponential phase
47
What are secondary metabolites?
Produced during the stationary phase and are collected at the end of the stationary phase or during the decline phase
48
What is an immobilised enzyme?
An enzyme which is held in place and is not free to diffuse through a solution
49
What are the advantages of immobilised enzymes?
- enzymes do not mix with the product so extraction rates are lower
- enzymes are reused easily
- continuous process is made easier (no cells requireing nutrients, reproducing and releasing waste)
- enzymes are surrounded by immobilising matrix which protects them from extreme conditions so higher temperatures and wider pH range can be used without denaturing
50
What are the methods used to immobilise enzymes?
- adsorption
- covalent bonding
- entrapment
- membrane separation
51
How does adsorption work on immobilised enzymes?
- enzyme molecules bound to a supporting surface
- bound by hydrophobic interactions and ionic links
- surfaces include clay, porous carbon, glass beads and resins
- enzymes are bound with active sites exposed
- active site may be slightly distorted by additional interactions
- bond forces are not always strong and enzymes become detached and leak into reaction mixture
52
How does covalent bonding work on immobilised enzymes?
- enzymes bonded to a supporting surface (clay)
- bound by strong covalent bonds
- enzymes are bonded using a cross-linking agent
- production of ovalen bonds can be expensive and can distort the enzyme active site
- enzymes are less likely to become detached
53
How does entrapment work on immobilised enzymes?
- enzymes are trapped in a matrix which does not allow free movement
- enzyme molecules are unaffected and remain fully actice
- substrate molecules must diffuse through entrapment matrix and product molecules must be able to diffuse out
- only suitable for processes where the substrate and product molecules are relatively small
- calcium alginate beads often used by schools
54
How does membrane separation work on immobilised enzymes?
- enzyme molecules are separated from reaction mixture by a partially permeable membrane
- substrate and product molecules must be small enough to pass through partially permeable membrane by diffusion
55
What is are industrial uses of immobilised enxymes and explain what they do?
- glucose isomerase (converts glucose to fructose which is used to produce high fructose corn syrup which is sweeter than sucrose)
- penicillin acylase (formation of semi-synthetic penicillins like amoxicillin)
- lactase (converts lactose to glucose and galactose by hydrolysis to make lactose free milk)
- aminoacylase (used to produce pure samples of L amino acids by removing the acyl group from the nitrogen of an N acyl amino acid
- glucoamylase (converts dextrins to glucose, used in fermentation)
