6.4 Flashcards
What are clones?
Genetically identical organisms or cells
Advantages of natural cloning
- cloning is relatively rapid so population can increase fairly quickly
- reproduction can be carried out even if there is only one parent, where sexual reproduction can’t happen
Disadvantages of natural cloning
- offspring may become overcrowded
- There will be no genetic diversity (apart from that caused by mutations in DNA replication)
- the population shows little variation
- an environmental change means the whole population is affected
What is vegetative propagation
plant clones being created from vegetative parts of a plant
what are 4 kinds of stems plants can produce clones
- Runners
- Stolons
- rhizomes
- suckers
what are runners and stolons
horizontal stems that grow on the surface of the ground that will produce a clone
What are rhizomes
horizontal stems the grow beneath the ground
what are suckers
new stems that grow from the
what are bulbs
fleshy underground stem from which grow leaves and they also have an apical bud that allows flowers to grow in spring
What are corms
similar to bulb but solid not fleshy
What plant reproduces asexually from its leaves
the kalanchoe
when does cloning happen in animals
when the zygote splits to become two separate cells resulting in twins
what are 3 ways of artificially cloning plants
cuttings
tissue culture
micropropagation
how do clone a plant through cuttings
to make a cutting, a stem is cut between two leafy joints (nodes) and may be dipped in rooting hormone and then is put in moist soil.
May also be useful to remove the bark from the end of the stem so pant produces a callus.
what other parts of the plant can cuttings be made
- root cuttings, where a section of the root is buried below the soil surface and so it produces new shoots
- scion cuttings, which are dormant woody twigs
- leaf cuttings, where a leaf is placed in the soil and it produces new stems
what is tissue culture
is a series of techniques used to grow plants from samples in a nutrient medium on sterile conditions
what is micropropagation
growing large numbers of new plants from meristem tissue taken from a sample plant
what are the steps of microporopagation
- meristem tissue taken, these are called explants
- explants are steralised using alcohol
- explants placed on sterile growth medium contains hormones
- a callus forms and it is divided into a large number of small clumps of undifferentitated cells
- small clumps of cells moved to different growth medium and small plantlets are formed
advantages of artificial cloning
- cloning is faster than growing from seeds
- cloning can happen where sexual reproduction can’t
- means plants are genetical identical so show desirable charictaristics
- all plants grown are uniform so easier to harvest
- using meristem as an explant ensures new plants are free from viruses
disadvantages of artificial cloning
- tissue culture is labour intensive
- expensive
- no genetic variation
what are totipotent cells
the can differentitate into any cells
what is embryo twinning/ splitting
splitting an embryo to create two genetically identical embryos
steps of embryo twinning/ splitting
- a zygote is created in IVF
- zygote is allowed to divide by mitosis to form a small ball of cells
- cells are seperated and allowed to continue dividing
- each small mass of cells is placed into the uterus of a surrogate mother
steps of somatic nuclear cell transfer
- an egg cell is obtained and its nucleus is removed
- a body cell of the adult to be cloned is obtained(called somatic cell)
- the somatic cell is fused with the egg cell by an electric shock
- electric shock also causes cell to start developing as if it had been fertilised
- cell undergoes mitosis
- embryo is placed in surragote mother
what is therapeutic cloning
new tissue and organs that can be grown as replacement parts for people who are not well
arguments for artificial cloning
- can produce a whole herd of animals with high yeild
- testing medical drugs on cloned cells and tissues avoids using them on animals or people for testing
- individuals form an endangered species can be cloned to increase numbers
arguments against artificial cloning
-cloned animals may be less healthy
-very expensive for a low success rate
advantages of using microorganisms in biotechnology
- cheap
- easy to grow
- reproduce quickly
- can be fed by-products from other food industires
- production can take place anywhere as not dependent on climate
- fewer ethical issues
how is biotechnology used in production of yogurt
fermented milk
bacteria convert lactose to lactic acid
the acidity denatures proteins causing coagulation
how is biotechnology used in the production of cheese
- bacteria converts lactose to lactic acid
- acidified milk is mixed with rennin
- rennin coagulates casein in presence of calcium ions
- curd forms that is pressed into moulds
how is biotechnology used in baking
- ingredients are mixed together to form dough
- the yeast in the dough respires anaerobically producing carbon dioxide bubbles causing dough to rise
- the dough is baked and any alcohol evaporates
how is biotechnology used in the production of alcoholic bevrages
wine
-yeast on surface of grapes respires anaerobically using sugar in crushed grapes
beer
-malting grains convert starch to maltose which is respired by yeast.
disadvantages of using microorganisms
- some people may not want to eat food grown on waste
- protein does not have the same taste texture as traditional protein
- risk of infection of proteins
- proteins have to be purified
how do you scale up the production of drugs
fermenters
what conditions need to be controlled to produce the greatest yield of drugs
- temperature
- nutrients available
- oxygen availability
- pH
- concentration of product
what are primary metabolites
products that are produced when microorganisms are growing and metabolising normally
how often can primary metabolites be collected
can be collected continuously from brroth
what is continuous culture
removing some of the broth regularly to remove the product and cells otherwise population becomes to dense
what are secondary metabolites
products that are produce when the cells are placed under high stress levels like having limited nutrient availability
what is batch culture
when the cells are set up with limited variables and time in the feremnter and it is emptied to collect the secondary metabolites
what is asepsis
ensuring sterile conditions are maintained
why is asepsis essential
the nutreint medium the cells grow on can support unwanted growth of other microorganisms
what can these unwanted microorganisms do in the fermenter
reduce the yeild of product
spoil the product
produce toxic chemiclas
compete with the culture
where is penicillin mass produced
fermenter
what type of metabolite is penicillin
secondary metabolite so manufactured through batch culture
how is penicillin produced
- fermenter is left to run for 8 days then culture if filtered to remove cells
- antibiotic is precipitated as crystals by addition of potassium compounds
-antibiotic is mixed with inert substances
and prepared as tablets or syrups
what is bioremediation
the use of microorganisms to clean the soil on polluted sited by converting the toxic pollutants to less harmful substances
what does bioremediation involve
- stimulating the growth of microorganisms that use contaminants as a source of food.
- need water, suitable temperature, suitable pH
advantages of bioremedation
- uses natural systems
- less labour needed
- treatment in situ
- few waste product
- less risk of exposure to clean-up personal of toxic chemicals
disadvantage of bioremedation
heavy metals can not be treated
what are they 2 types of common growth mediums microorganisms are grown on
- broth (soup like liquid)
- agar which is melted into petri dishes
what are 6 aspectic techniques that reduce the likelihood of contaminating medium with unwanted microorganisms
- wash hands
- disinfect working area
- have a Bunsen burner to heat air around work space to prevent air-borne microorganisms settling and make sterile air
- as you open a bottle pass its neck over the flame to prevent microorganisms in air from entering
- don not lift lid of petri dish completly
- any metal/glass equipment should also be passed through flame before being allowed to come into contact with desired microorganisms
what are the 3 steps of growing microorganisms on agar plates
- sterilisation
- inoculation
- incubation
how to sterilise agar
agar medium is heated in an autoclave at 121 degrees for 15 minutes which kills any living microorganisms and then it is poured into petri dishes once cooled and then lid is placed
what is inoculation
inoculation is the introduction of microorganisms to the sterile medium
what are 4 ways of inoculation
- streaking, a wire loop transfers a small amount of liquid onto agar and it is spread out
- seeding, a sterile pipette can be used to transfer a small amount of the liquid onto agar
-spreading, a glass spreader can be used
to spread the liquid drop across the agar
- a cotton bud can collect microorganisms from one surface and transfer them to another
how are petri dishes incubated
petri dish is placed upside down in an incubator to prevent condensation drops falling on agar and it drying out to quick, dish should not be sealed completely as this could result in potentially pathogenic anaerobic microorganisms
what is a closed culture
a population in which all conditions are set at the start and there is no exchange with the external environment
what are immobilised enezymes
an enzyme that held in place and not free to diffuse through the solution
advantages of immobilising enzymes
- enzymes do not mix with product so extraction is cheaper
- enzyme can be easily reused
- continuous processes are made easier
- enzymes protected from extreme conditions as they are surrounded by immobilising matrix
disadvantages of immobilising enzymes
- expensive
- immobilised enzymes are less active so rate of reaction is slower
what are 4 methods used to immobilise enzymes
- adsorption
- covalent bonding
- entrapment
- membrane seperation
how does adsorption work
enzymes are bounded to a surface like clay, porous carbon, resins or glass beads
by hydrophobic and ionic bonds
advantages of adsorption
cheap
disadvantages of adsorption
- hydrophobic and ionic bonds are weaker so there is a chance of them breaking and enzyme falling into mixture
- bonds may chnage shape of enzyme site resulting in lower activity
how does covalent bonding work for immobilising enzymes
enzymes are bounded to a surface like clay, porous carbon, resins or glass beads by covalent bonds
advantages of using covalent bonds
- stronger so less likely for enzymes to break off
- enzymes can attach to each pother via covalent bonds
disadvantages of using covalent bonds
- expensive
- -bonds may chnage shape of enzyme site resulting in lower activity
how does entrapment work
enzymes are trapped in a cellulose matrix that does not allow movement of enzymes but they remain active
advantage of entrapment
enzymes remain fully active so reaction rate does not change
disadvantage of entrapment
molecules need to be small
how does membrane separation work
-are separated form the reaction mixture via a partially permeable membrane
advantage of membrane sepeation
enzyme remains fully active so no change in reaction rate
disadvantage of membrane serperation
molecules must be small
what does glucose ismoerase do
- coverts glucose to fructose
- used to produce high fructose corn syrup which is very sweet makes low calorie foods
what does penicillin acylase do
creates synthetic penicillin
what does lactase do
coverts lactose to glucose and galactose
what does amino acylase do
produces pure samples of L-amino acids
what does glucoamylase do
converts dextrins to glucose
what does nitrile hydrase do
converts nitriles to aimides
