6.4 cloning and biotechnology Flashcards
define clones
genetically identicl organisms or cells
define vegetative propagation
reproduction from vegetative parts of plants usually from an over-winering organ
Give some examples of natural cloning
mitosis
yeast in budding
bacteria in binary fission
what are the advantages of natural cloning
cloning is relatively rapid
reproduction can be carried out even if there is only one parent
if conditions of growth are good for parent it will be good for offspring
What are some disadvantages of natural clones
offspring may be overcrowded
no genetic diversity
population shows little variation
selection is not possible
population is susceptible to changes
Why might natural cloning be used in horticulture
to increase the number of plants
What are runners or stolens
Horizontal stems above ground that can form roots at certain points
What are rhizomes
horizontal stems below ground that are able to form roots at certain points
What are suckers
new stems that grow from the roots of plants
What are bulbs
over-wintering mechanism
they consist of an underground stem from which grow a series of fleshy leaf bases there is also an apical bud which will grow into a new plant
What are corms
Underground stem with scaly leaves and buds
they remain in the ground over winter and produce one or more new plants in spring
How do bulbs and corms differ
Corms are solid rather than fleshy like bulbs
how can leaves propogate
kalanchoe plants reproduce asexually as clones grow on the leaf margins and immature plants drop off and take root
What are tubers
another type of underground stem
potatoes are tubers and one potato will grow into one or more plants each new plant can produce many new tubers
Give examples of natural cloning in animals
Mammals clone when twins are forms - the zygote divides as normal but the two daughter cells split into two separate cells
water flea
green fly
Why is asexual reproduction quicker
no need for finding a mate going through courtship meiosis and fertilisation
why are plants more likely to reproduce asexually
the cells do not differentiate as completely
there are areas of meristem in the plant
why is it an advantage for small mobile animals to be able to reproduces asexually
able to take advantage of favourable environment quickly so there is no need to find a mate
if conditions ideal fro parent the will be ideal for the offspring
why is it likely a plant such as kalanchoe will become overcrowded
the offspring will not be dispersed well and grow close to the parent plant
suggest why many plants will grow suckers after the main stem has been damaged
The main stem releases plant hormones or growth substances. If production is changed (by cutting the stem) the roots are stimulated to grow suckers. Changing conditions, such as less shade after stem has been cut, may also stimulate roots to grow suckers.
the new stem will grow as a separate individual
Describe how to make a cutting
stem is cut between two leaf joints(nodes) and the cut end is placed in moist soil
new roots will grow from the tissues in the stem
How can we help stimulate root growth in cuttings
Dipping them in rooting hormones
Why are cutting used
can be used to produce large numbers of plants quickly
What other parts of the plant can cuttings be made from
root
scion- dormant woody twigs
leaf
Why are cuttings not used for large-scale cloning
time-consuming and require a lot of space and some plants do not respond well to cuttings
Define tissue culture
growing new tissues organs or plants from certain tissues cut from a sample plant
Under what conditions iws tissue culture carried out
sterile
Define micropropagation
growing large numbers of new plants from meristem tissue taken from a sample plant
What are explants
plant material selected and cut into pieces
Why are explants usually meristem
always free from virus infection
what is a callus
a mass of undifferentiated totipotent cells
Describe the steps involved in micropropagation
explant is collected
explant is sterilised using alcohol or dilute bleach to kill any bacteria or fungi
explants are placed on a sterile growth medium such as agar gel containing suitable nutrients such as glucose and high concentrations of auxin and cytokinin which stimulates cells of explant to divide by mitosis to form a callus
callus is divided to form a larger number of small clumps of undifferentiated cells
small callus clumps are then stimulated to grow divide and differentiate to plant tissues by moving them to different growth media
once plantlets are formed they are transferred to a greenhouse and compost
describe the different ratios of the growth media that the callus clumps are transferred to during micropropagation
100:1 auxin:cytokinin - stimulates root formation
4:1 auxin:cytokinin - stimulates shoot formation
What are the advantages of artificial plant cloning
relatively rapid
can be carried out where sexual reproduction is not possible
plants are all genetically identical
uniform in phenotypes
ensures plants are virus free
What are some disadvantages of artificial cloning of plants
labour intensive
expensive
can fail due to microbial contamination
cloned offspring will be susceptible to the same pathogens
no genetic variation
why do the new roots usually grow from the node
The node contains a meristem (this may be a dormant bud). This is a group of cells that can divide and
differentiate into different cell types. The side branch would normally grow from this meristem, but if the cutting is planted in moist soil, roots will grow.
define enucleation
removal of a cell nucleus
define embryo twinning
splitting an embryo to create two genetically identical embryos
Define somatic cell nuclear transfer
technique that involves transferring the nucleus from a somatic cell to an egg cell
What kind of cells does successful artificial cloning in animals begin with
totipotent cells - very early embryo cells
Why may animal cloning be useful
produce elite farm animals
genetically modified animals such as goats which produce spider silk in their milk
Describe the process of embryo splitting
a zygote is created in IVF and allowed to divide by mitosis to form a small ball
the cells are separated and allowed to continue dividing
each small mass is placed in the uterus of the surrogate mother
produced offspring are all clones
Why might embryo splitting be used
2 high value cows may be bred together to produce many high value calfs
What is a setback of of embryo splitting
the precise genotype and phenotype of offspring depend on sperm and egg used so precise phenotypes will not be known till offspring are born
What are some examples of reproductive cloning
embryo splitting
somatic cell nuclear transfer
Describe the process of somatic cell nuclear transfer
an egg cell is obtained and enucleated
a somatic cell is isolated and has the nucleus removed
the somatic cell and empty egg cell are fused by applying an electric shock this causes the egg cell to start developing as though it had just been fertilised
the cell undergoes mitosis to form a small ball of cells and is then planted in a surrogate mother
Why might SMCT have an advantage over embryo winning
the phenotype of the offspring are already known
what are some examples of non-reproductive cloning
therapeutic and cloning for scientific research
what are some examples of therapeutic cloning
skin cells grown in vitro for grafts on burn victims
potential to grow whole organs to replace diseased organs
What are some examples of cloning for scientific research
to test drugs
research into action of genes that control development and differentiation
What are some arguments for artificial cloning in animals
can produce a herd of animals with a high yield showing desirable or unusual characteristics - spider goats
genetically identical high value animals
allows drug testing without using animals
endangered individuals can be cloned to increase numbers
less chance of rejection when used for transplants or repairing damage
What are some arguments against artificial cloning in animals
lack of genetic variation
success rate of adult cell cloning is poor
ethical issues associated with length of embryo survival
doesn’t help increase genetic diversity
Define biotechnology
The use of living organisms or parts of living organisms in industrial processes
Give some examples of biotechnology in food
ethanol in beer and wine - yeast
CO2 to make bread rise - yeast
lactic acid to make yoghurt and cheese - lactobacillus bacteria
Give some examples of biotechnology in pharmaceuticals
penicillin - penicillium fungus
insulin and other therapeutic human proteins - genetically modified bacteria
Give some examples of enzymes in biotechnology
protease and lipase used in washing powders - bacteria
lactase to make lactose free milk - A.niger A.oryzae
protease used to tenderise meat - Aspergillus spp
Give some examples of biotechnology in other products
biogas - anaerobic bacteria
bioremediation - cleaning waste water - variety of bacteria and fungus
What are the advantages of using microorganisms in biotechnology
Relatively cheap and easy to grow
production takes place at low temperatures and normal pressure
production is not dependant on climate
can be fed by products from other industries
reproduce quickly
fewer ethical consideration
can be easily genetically modified
How are other organisms used in biotechnology
Genetic modification if mammals such as goats which produce spiders silk in their milk and cows which produce human antibodies
Give other forms of biotechnology other than industrial processes
gene technology
selective breeding
immunology
cloning
gene modification and gene therapy
How is yoghurt produced
milk undergoes fermentation and the bacteria convert lactose into lactic acid and the acidity denatures the milk protein causing it to coagulate
what are probiotics
bacteria which may benefit human health by improving digestion, stimulating the immune system or aiding gastrointestinal function
How is cheese produced
acidified milk is mixed with rennet which contains the enzyme rennin which coagulates the milk protein in the presence of calcium ions and the curd is then pressed into molds
what are the three steps in bread making
mixing
proving
cooking
Describe why the steps in baking are important
proving produces carbon dioxide and and causes the dough to rise
cooking evaporates alcohol out of the dough
describe how alcoholic beverages are produced
yeast uses sugars in fruit to produce carbon dioxide and alcohol
malting - as grain germinates it converts stored starch to maltose which is respired by the yeast
What are single cell proteins
manufacture of protein that is directly used as food for example Quorn
these microorganisms can produce a protein with a similar amino acid to animal and plant protein and can grow on almost any organic substrate including waste such as whey
What are some advantages of SCP
production is faster
biomass has very high protein content
production can be increased according to demand
no animal welfare issues
no animal fat or cholesterol
what are some disadvantages of SCP
does not have a taste or texture
conditions needed are also ideal for pathogens
some people do not want to eat fungal protein or food grown on waste
protein has to be purified to ensure it is uncontaminated
What are the 10 components of a fermenter
pressure vent
air inlet
mixing blades
water jacket
outlet tap
air outlet
electronic probes
water jacket outlet
inlet for nutrients
motor
What are the different types of culture
batch and continuous
what type of metabolites are associated with batch cultures
secondary
What type of metabolites are associated with continuous culture
primary
define primary metabolite
products are continuously released and can be extracted continuously from the fermenting broth usually in log phase-insulin
define continuous culture
some of the broth is removed regularly and there is a constant nutrient supply
define secondary metabolite
produced when cells are placed under stress such as high population density or limited nutrients and often occurs during stationary phase-penicillin
define batch culture
culture is set up with a limited quantity and allowed to ferment for a specific time and after the fermenter is empties
Define asepsis
ensuring sterile conditions are maintined
what do unwanted microorganisms do to a culture
compete with cultured microorganisms for space and nutrients
reduce yield of useful product
spoil the product
destroy the cultured microorganism may produce toxic chemicals
define bioremediation
the use of microorganism to clean soil and underground water on polluted sites by converting toxic pollutants to less harmful substances
What conditions does bioremediation require and what happens if these arent reached
available water
suitable temperature
suitable pH
they may be modified by the addition of suitable substances e.g. additional nutrients may be added to ensure microorganisms can grow effectively or oxygen may be pumped
what are the advantages of bioremediation
uses natural systems
less labour and equipment required
treatment in situ
few waste products
less exposure risk to clean up crew
What are the disadvantages of bioremediation
only suitable for certain products and heavy metals such as cadmium and lead cannot be treated
Define aseptic technique
developed to reduce the likelihood of contaminating medium with unwanted bacteria or fungin
What are the three main steps for growing microorganisms on agar plates
sterilisation, inoculation, incubation
describe sterilisation
medium is sterilised by heating an an autoclave at 121 for 15mins and from that point onwards equipment is sterilised by heating
describe inoculation
streaking
spreading
seeding
moist cotton swab
describe incubation
labelled petri dish has bottom and top taped with 2 strips of adhesive but not fully as to prevent anaerobic bacteria formation,
placed in a warm environment of the suitable temperature
placed upside down so condensation doesn’t fall on the agar
What is a serial dilution
sequence of dilutions used to reduce the concentration of a solution or suspension
What is the purpose of a serial dilution in culturing
reduces the population density of the microorganism as too many colonies may merge making it impossible to count
What are the phases in the bacteria growth curve
lag
log
stationary
death
Describe the lag phase in bacteria
population is small and adjusting to the new environments this may involve
water uptake
cell growth
switching on certain genes
synthesising specific proteins
Describe the log phase in bacteria
each have the enzymes needed to survive and each individual has sufficient nutrients to grow rapidly and frequently
Describe the stationary phase in bacteria
the rate of population growth declines and the number of individuals dying increases until reproduction rate is equal to growth rate
Describe the decline phase in bacteria
nutrients run out and concentration of waste products may become lethal
define immobilised enzymes
enzyme that is held in place and not free to diffuse through the solution
what are the advantages of immobilised enzymes
extraction costs are lower
enzymes can be easily reused
continuous process is made easier as there are no cells requiring nutrients or producing waste products
immobilising matrix protects them from extreme conditions
What are the disadvantages of immobilised enzymes
usually less active than free enzymes making the process slower
What are the methods used to immobilise enzymes
adsorption
covalent bonding
entrapment
membrane separation
Describe how enzymes are immobilised using adsorption
enzyme molecules are bound to a supporting surface by a combination of hydrophobic interaction and ionic links
suitable surfaces include clay, resin and glass beads
What are the drawbacks of using adsorption to immobilise enzymes
active sight may be slightly distorted and additional interactions may affect enzyme activity
enzymes can also get detached and leak into the reaction mixture
describe how enzymes are immobilised using covalent bonding
enzyme molecules are bonded to a supporting surface such as clay using strong covalent bonds and cross-linking agents which may also link them in a chain
less likely to become detached
what are the drawbacks of using covalent bonds to immobilised enzymes
expensive and can distort the active site
Describe how enzymes are immobilised using entrapment
they are trapped in a matrix that does not allow free movement
What are the advantages of entrapment
enzyme molecules are unaffected and remain fully active
What are the disadvantages of entrapment
molecules must diffuse into the matrix and product molecules must be able to diffuse out the method is therefore only suitable for processes where the substrate and product molecules are very small
Describe how enzymes can be immobilised using membrane separation
enzyme molecules are separated from the reaction mixture by a partially permeable membrane and similarly to entrapment the substrate and product must be small enough to diffuse through the partially permeable membrane and this may limit the enzyme reaction rate
What are some of the examples of immobilised enzymes used in industry
glucose isomerase
penicillin acylase
lactase
aminoacyclase
glucoamylase
nitrile hydratase
Describe the industrial uses of glucose isomerase
converts glucose to fructose
used to produce high-fructose corn syrups that is often used in diet foods
Describe the industrial uses of penicillin acylase
formation of semi-synthetic penicillin’s such as amoxicillin
Describe the industrial uses of aminoacyclase
used to produce pure samples of L-amino acids which are the building blocks for synthesis of a number of pharmaceutical and agrochemical compounds
Describe the industrial uses of lactase
converts lactose to glucose and galactose by hydrolysis used to produce lactose-free milk
Describe the industrial uses of glucoamylase
converts dextrin to glucose and the enzyme is used in a wide variety of fermentation processes including conversion of starch pulp to alcohol to gasohol used in motor vehicles
dextrin produced by hydrolysis of starch
Describe the industrial uses of nitrile hydratase
converts nitriles to amides
including acrylonitrile to acrylamide which can be converted to polyacrylamide which is a plastic used as a thickener -
helps stick contaminants in water together so that they are precipitaed and easy to filter out of water
