6.2.1 - Cloning and Biotechnology Flashcards
1
Q
What is a clone?
A
a genetically identical organism
-produced by asexual reproduction
2
Q
What is vegetative propogation?
A
asexual reproduction in plants where a structure (eg. stem, root, leaf, bud) which can differentiate into a fully grown plant
-produces a clone
3
Q
Name some examples of natural vegetative propagation
A
- using rhizomes (eg. bamboo, raspberries, nettles, etc)
- using runners (eg. strawberries, spider plants, etc)
- using suckers (eg. elm trees)
- using tubers (eg. potatoes)
- using bulbs (eg. daffodils, tulips, etc)
4
Q
How do plants undergo vegetative propagation using rhizomes?
A
a rhizome is a stem-like structure that grow horizontally underground from the plant, which produces nodes that shoots and roots can develop from
eg. bamboo, raspberries, nettles
5
Q
How do plants undergo vegetative propagation using runners?
A
runners are stem-like structures that grow horizontally above ground from the plant, which produces nodes that shoots and roots can develop from when the nodes are in contact with the ground
eg. strawberries, spider plants, etc
6
Q
How do plants undergo vegetative propagation using suckers?
A
suckers are shoots that grow from sucker bulbs (undeveloped shoots)
eg. elm trees
7
Q
How do plants undergo vegetative propagation using tubers?
A
tubers are swollen underground food stores attached to plant’s stem which has eyes that new plants can sprout from
eg. potatoes
8
Q
How do plants undergo vegetative propagation using bulbs?
A
bulbs are swollen leaf bases that acts as food stores
new bulbs can develop from a bulb and grow to form new plants
eg. daffodils, tulips, etc
9
Q
How can plant cuttings be used to clone plants?
A
- a section of stem is cut from the plant
- cutting is placed in rooting powder (containing plant hormones like auxins and cytokines which stimulate root growth)
- cutting is planted into a pot containing compost/growth medium
- when the cutting has developed roots, it can be planted into soil
10
Q
What is grafting?
A
when a plant shoot is placed into a slit in the base of another plant (a graft) so that their tissues grow together to produce a plant with both plants characteristics
- base is chosen for its characteristics (eg. tall/short plant) which are required for the shoot
eg. used with fruit plants
11
Q
What is micropropagation?
A
the process of making large numbers of cloned (genetically identical) plants from a single parent plant using tissue culture
12
Q
What happens in tissue culture?
A
- tissue samples (containing many cells) are taken from the plant
- tissue samples are transferred to a sterile agar plate
- plant hormones are added to the agar plates (to stimulate cells to divide)
- each group of cells divides to form a callus
- each callus is separated into a number of groups of cells so more clone plants can be produced
- plantlets are produced and transferred to pots containing soil and are grown around 20°C for maximum growth
- lots of clone plants are produced
13
Q
When is tissue cultured/micropropagation used?
A
- to clone endangered/rare plants (conservation)
- to grow genetically engineered plants
- to grow plants that don’t readily reproduce
- to grow pathogen-free plants (eg. strawberries, bananas, potatoes)
- to produce plants which produce medicines
- for agriculture and horticulture
- for commercial uses (to produce orchids, grapes, sugar cane, potatoes, bananas, strawberries, etc)
14
Q
What are the arguments for artificial plant cloning?
A
- lots of plants are produced quickly (quicker than growing from seed)
- desired characteristics are always passed on
- tissue culture allows plants to be reproduced in any season (environment is controlled)
- less space required for tissue culture
- infertile plants can be grown
- plants producing seedless fruits can be grown
- disease-free plants can be grown
15
Q
What are the arguments against artificial plant cloning?
A
- plants produced are all genetically identical so are susceptible to disease and climate change
- expensive (high energy use)
- requires skilled workers
- explants are susceptible to contamination (need sterile conditions)
- large numbers can be lost in the process
16
Q
How are clones produced naturally in animals?
A
embryo splits to produce identical twins
17
Q
Excluding twins, how can animals naturally produce clones of themselves?
A
- by fragmentation -in star fish
- by binary fission -in flatworms
- by budding -in hydra
these are all invertebrates so not too complex to clone
18
Q
How can animal clones be artificially produced?
A
- artificial embryo twinning
- somatic cell nuclear transfer (SCNT)
19
Q
How are clones produced artificially using artificial embryo twinning?
A
- embryo is produced by IVF (egg cell is extracted from a female and fertilised in a petri dish and left to divide to form an embryo) or artificial insemination (animal is given hormones to super ovulate and sperm is added so that egg is fertilised, which is then removed from the uterus)
- embryo cells are separated (around day 6) and then grown to produce multiple embryos
- embryos are implanted into surrogate mothers
- embryos develop in surrogate mothers and clones are born
20
Q
Why are embryos implanted into different surrogate mothers during artificial cloning?
A
single pregnancies have fewer risks
21
Q
What does SCNT stand for?
A
somatic cell nuclear transfer
22
Q
How are clones produced artificially using somatic cell nuclear transfer (SCNT)?
A
- a nucleus is separated from a somatic cell of the donor
- an egg cell is taken from another animal and its nucleus is removed (the cell is enucleated)
- the nucleus from the donor is fused with the enucleated egg cell using an electric shock
- the fused cell divides and forms an embryo
- the embryo is transferred to a surrogate mother and develops and a clone is born
23
Q
Why is somatic cell nuclear transfer classed as asexual reprouction?
A
there is no fertilisation involved
24
Q
Why are different breeds of sheep used for the egg cell in somatic cell nuclear transfer?
A
to prove cloning was successful and that the clone has genetic material of the other sheep
25
Why does the cloned animal produced by somatic cell nuclear transfer not have the exact same genetic material as the donor?
the cloned animal's mitochondrial DNA comes from the egg cell
26
What are the arguments for artificial animal cloning?
- desired characteristics are always passed on
- infertile animals can be reproduced
- SCNT can be used to clone specific animals, such as rare/endangered animals, pets, high value animals, etc
- artificial twinning enables production of many high yielding animals
- in SCNT, genetically modified animals can be cloned
27
What are the arguments against artificial animal cloning?
- SCNT is an inefficient process (rare to produce a viable clone + many embryos fail to survive)
- no genetic diversity so are susceptible to disease and climate change
- clones might not live as long as natural offspring
- people disagree with genetically modified animals, particularly as food sources
28
What is biotechnology?
the industrial use of living organisms (or parts of living organisms) to produce food, drugs or other products for human use
-usually using microorganisms
29
Why are microorganisms used in biotechnological processes?
- short life cycle (grow rapidly)
- easy to create their ideal growth conditions (nutrients, temp, pH, moisture levels, etc)
- economical to use because they can be grown on a range of cheap materials
- can be grown at any time of year
30
Name some examples of biotechnological processes which use microorganisms
- brewing
- baking
- cheese making
- yogurt production
- penicillin production
- insulin production
- bioremediation
31
What microorganism is involved in brewing?
yeast
32
What are the steps in brewing?
- malting: barley germinates, which produces enzymes that break starch into sugars and malt is produced
- mashing: malt is mixed with hot water and enzymes break malt into wort (which is sterilised and cooled)
- fermentation: yeast uses wort for anaerobic respiration and produces ethanol
33
What microorganism is involved in baking?
yeast
34
What are the steps in baking?
- active yeast is added to ingredients and is mixed and left in a warm environment to rise (yeast produces CO2, which causes the bread to rise)
- dough is kneaded
- dough is cooked in hot oven (more CO2 produced causes it to rise more)
35
What microorganism is involved in cheese making?
```
bacteria
chymosin enzyme (in rennet)
```
36
What are the steps in cheese making?
- milk is pasteurised (heated to kill bacteria) and homogenised (mixed so fat is evenly distributed)
- bacteria cultures and rennet (containing chymosin enzyme) are added to milk
- milk separates into curd and whey
- for most cheeses, whey is strained and curds are cut, pressed, etc into cheese
37
What microorganism is involved in yogurt production?
bacteria
38
What are the steps in yogurt production?
- milk is pasteurised and homogenised
- bacteria (such as Lactobacillus bulgaricus and Streptococcus) are added and incubated
- bacteria produce lactic acid (lactate fermentation), which decreases the pH so that the proteins in the milk coagulate/thicken
39
What microorganism is involved in penicillin production?
fungus (Penicillium chrysogenum)
40
What are the steps in penicillin production?
- fungus is grown in a fermenter
| - fungus produces penicillin, which is then extracted
41
What microorganism is involved in insulin production?
genetically modified bacteria (eg. E.coli)
42
What are the steps in insulin production?
- genetically modified bacteria are grown in a fermenter
| - they produce pure human insulin
43
What microorganism is involved in bioremediation?
natural or genetically modified organisms (depends on what is being broken down)
44
What is bioremediation?
when microorganisms break down organic matter (eg. pollutants and contaminants in soil or water)
45
Why is milk pasteurised for cheese and yogurt production?
- to kill bacteria
- prevents contamination
- reduces competition
46
What are the advantages of using microorganisms to make food for human consumption?
- microorganisms grow and reproduce quickly
- low production costs (as microorganisms have simple growth requirements)
- microorganisms can be grown on waste products
- microorganisms don't take up a lot of room)
- microorganisms can be cultured anywhere and is not dependant on weather, breeding cycles, etc
- no welfare issues
47
What are the disadvantages of using microorganisms to make food for human consumption?
- sterile conditions need to be maintained (to avoid contamination)
- some microorganisms could produce toxins if optimum conditions aren't maintained
- some people have concerns about eating food produced by genetically modified organisms
- some people don't like the idea that the food has been grown using waste products
48
What are aseptic techniques?
techniques used to culture microorganisms in sterile conditions
-prevents contamination from unwanted microorganisms
49
How do you culture microorganisms in the lab?
- microorganisms are transferred from a sample to an agar plate (petri dish containing agar jelly) using a sterile implement (like a wire loop or pipette and spreader)
- nutrients can be added (to improve growing conditions)
- plates are incubated
50
What aseptic techniques could you use to culture microorganisms in the lab?
- disinfect work surfaces
- work near a Bunsen burner
- sterilise equipment before and after use
- just as any bottles are opened or when they are about to be closed, the neck of the bottle should be briefly passed through the Bunsen burner flame
- minimise time agar plate is open by putting lid back on as soon as possible
51
What are the two types of fermenters?
- batch fermenter
| - continuous fermenter
52
What is batch fermentation?
when microorganisms are grown in individual batches in a fermenter
- the process is stopped before death phase and products are harvested
- fermenter is cleaned and sterilised before the next batch is added
53
What is coninuous fermentation?
when microorganisms are continuously grown in a fermenter without stopping
-nutrient medium is continuously put in and waste products are continuously taken out
54
What are the advantages of batch fermentation?
- fermenter is smaller/simpler (so less space required)
- less susceptible to contamination
- if contaminated, only one batch is lost
- fermenter is more versatile
- reactions can go to completion
55
What are the disadvantages of batch fermentation?
- need to sterilise after each batch
- harder to monitor/maintain conditions
- less consistent quality of product
56
What are the advantages of continuous fermentation?
- more productive
- longer time intervals between sterilisations
- more consistent quality of product
57
What are the disadvantages of continuous fermentation?
- fermenters are larger and more complex (more space required)
- fermenters are less versatile
- more susceptible to contamination
- if contaminated, losses are high
58
What factors are regulated to maximise yield in a fermenter?
- pH
- temperature
- nutrient concentration
- volume of oxygen
59
How is pH regulated in a fermenter?
- monitoring using a pH probe
| - kept at optimum pH so any enzymes work efficiently
60
How is temperature regulated in a fermenter?
- monitoring using a temperature probe
| - fermenter is surrounded by a water jacket to keep temp constant for enzymes
61
How is the concentration of nutrients available regulated in a fermenter?
-paddle continuously circulates/mixes nutrient medium
62
How is the volume of air available regulated in a fermenter?
-sterile air is pumped into the vessel so microorganisms always have oxygen available for respiration
63
What are the phases in a standard growth curve for microorganisms in a closed culture?
- lag phase
- log phase
- stationary phase
- death phase
64
What happens during the lag phase of a standard growth curve for microorganisms in a closed culture?
- initial population remains constant
- bacteria are adapting/acclimatising to the environment
- bacteria are synthesising the enzymes they need
- bacteria are growing by absorbing water
- population begins to increase slowly (there is only a small population to asexually reproduce)
65
What happens during the log phase of a standard growth curve for microorganisms in a closed culture?
- bacteria population increases exponentially
- rate of reproduction increases (and is greater than death rate)
- there are optimum conditions (enough space, minerals, oxygen, water, amino acids, glucose, etc)
66
What happens during the stationary phase of a standard growth curve for microorganisms in a closed culture?
- bacteria population plateaus
- total growth rate is 0 as the reproduction rate is equal to the death rate
- reproduction/growth rate has slowed due to minerals, oxygen, water, amino acids or glucose becoming a limiting factor
67
What happens during the death phase of a standard growth curve for microorganisms in a closed culture?
- bacteria population decreases rapidly
- death rate is greater than reproduction rate
- bacteria have run out of space, minerals, oxygen, water, amino acids or glucose
68
What are primary metabolites?
substances produced as part of normal growth
- as biomass of organism increases, the production of primary metabolites increases
eg. enzymes, nucleic acids, proteins, etc
69
What are secondary metabolites?
substances not produced as a normal part of growth (produced after the main growth phase)
eg. antibiotics, pigments, toxic chemicals, etc
70
What are immobilised enzymes?
isolated enzymes attached to an inert, insoluble material
71
What are the methods of enzyme immobilisation?
- surface immobilisation by adsorption to inorganic carriers
- surface immobilisation by covalent or ionic bonding to inorganic carriers
- entrapment in a matrix
- membrane entrapment
72
How are enzymes immobilised by surface adsorption to an inorganic carrier?
enzyme adheres to the surface of an inorganic carrier (such as cellulose, silica, carbon monoxide, carbon nanotube, etc) using hydrophilic/hydrophobic interactions, London forces of hydrogen bonding
73
What are the advantages of immobilising enzymes by surface adsorption to an inorganic carrier?
- simple
- cheap
- enzymes are accessible
- enzyme activity is unchanged
74
What are the disadvantages of immobilising enzymes by surface adsorption to an inorganic carrier?
- enzymes can be lost relatively easily
| - enzymes could adsorb the wrong way round (blocking active site)
75
How are enzymes immobilised by surface adsorption by covalent or ionic bonding to an inorganic carrier?
enzyme forms covalent or ionic bonds to an inorganic carrier (eg. covalent bonds with carriers containing amino, hydroxy or carboxy groups or ionic bonds with carriers such as polysaccharides like cellulose and synthetic polymers)
76
What are the advantages of immobilising enzymes by surface adsorption by covalent or ionic bonding to an inorganic carrier?
- enzymes are strongly bound so less likely to be lost
- enzymes are very accessible to substrate
- enzymes are more stable so can work at more extreme temperatures and pHs
77
What are the disadvantages of immobilising enzymes by surface adsorption by covalent or ionic bonding to an inorganic carrier?
- active site could be modified in process, making it less effective
- bonds could form in positions blocking active site
78
How are enzymes immobilised by entrapment in a matrix?
enzyme is enclosed in a biomolecule in a small space (aka matrix, eg. polysaccharides, gelatine, agar)
-uses an inert membrane to provide contact between matrix and enzyme
79
What are the advantages of immobilising enzymes by entrapment in a matrix?
-is widely applicable to different processes
80
What are the disadvantages of immobilising enzymes by entrapment in a matrix?
- expensive
- can be difficult to entrap enzymes
- enzymes are easily lost
- entrapment can effect enzyme activity
81
How are enzymes immobilised by membrane entrapment?
enzyme is entrapped inside a microcapsule (eg. polymer-based semi-permeable membrane) or behind a semi-permeable membrane
82
What are the advantages of immobilising enzymes by entrapment in a membrane?
- enzymes are protected so temp is less of a worry
- simple
- relatively small effect on enzyme activity
- widely applicable to different processes
83
What are the disadvantages of immobilising enzymes by entrapment in a membrane?
-only works with smaller substrates which can get in and out of membrane
84
Name some examples of the use of immobilised enzymes in biotechnology
- converting glucose to fructose (to be used in slimming foods as it is sweeter)
- formation of semi-synthetic penicillins (which some organisms are not resistant to)
- converting lactose to glucose and galactose (for lactose free milk for lactose intolerant people)
- producing pure samples of L-amino acids (for use in cosmetics, food and pharmaceuticals)
- converting dextrins to glucose (in food industry)
85
What enzyme is immobilised to convert glucose to fructose?
glucose isomerase
86
What enzyme is immobilised to from semi-synthetic penicillins?
penicillin acylase
87
What enzyme is immobilised to convert lactose to glucose and galactose?
lactase
88
What enzyme is immobilised to produce pure samples of L-amino acids?
aminoacylase
89
What enzyme is immobilised to convert dextrins to glucose?
glucoamylase
