Cloning and Biotechnology

Question 1

Clones

Answer 1

-genetically identified organisms or cells
- produced by asexual reproduction so mitosis occurs

Question 2

Vegetative propagation

Answer 2

= Vegetative parts (figure 1) include roots, stems, shoot buds and leaves. They are not directly involved in sexual reproduction. Vegetative parts often are used in asexual forms of reproduction.
E.g. natural vegetative propagation
- tubers= such a potatoes
- bulbs = onions
-runners= strawberries ( above ground whiles the others are underground)

Question 3

Cuttings (type of vegetative propagation)

Answer 3

-cut is taken using a scalpel
- dip cutting into hormones to induce growth
- place in soil and allow to grow

Question 4

Micropropagation and tissue culture

Answer 4

• tissue culture= technique to grow cells, tissues and organs from a small sample
• Microprogation= type of tissue culture: growing large number of new plants from meristems tissues taken from sample plant.

Method:
- explant is taken from the plant usually meristems as they differentiate into any cell
- explant is sterilised
- explant is placed in a growth medium( usually agar jelly) which also contains high concentrations of growth hormones such as auxins and cytokinin to stimulate division by mitosis to form callus
- The callus is placed in a second growth medium with growth hormones
- once a tiny plantlets have been formed they are transferred to a greenhouse to be grown.

Question 5

Evaluation of artificial cloning

Answer 5

For:
- desirable characteristics will always be passed in to the clone
- plants can be reproduced in any season because environment is controlled
- produces lots of plants quickly
Against
- no genetic variability= increased vulnerability to disease
- tissue culture has high costs due to high energy used and training is skilled working
- may fail does to microbial contamination

Question 6

Natural clones in animals

Answer 6

• identical twins

Question 7

Embryo splitting

Answer 7

• artificial cloning in mammals, animal clone is not produced and phenotype is unknown
  1) a zygote ( fertilised egg) is created using IVF.
  2) zygote dived by mitosis to form a small ball of cells
  3) the cells are separated and allowed to continue divide
  4) each small mass of cell is placed in the uterus of surrogate mother

Question 8

Somatic cell nuclear transfer (SCNT)

Answer 8

• artificial clone in animals, adult clone is produced and phenotype is known before cloning is started
  -1) enucleation= removing of nucleus from a somatic cell ( body cell that isn’t a gamete)
  2) the nucleus is fused with an empty egg cell by an electric shock (electrofusion)
  3) the shock triggers the egg cell to develop as of it’s been fertiliser
  4) undergoes mitosis to form a small ball of cells
  5) the cells are placed in the uterus of surrogate mother

Question 9

Uses of cloning

Answer 9

-scientific research = test new drugs as the clones are genetically identical so there no differences
- save endangered animals from extinction
- increase the number of animals with desirable characteristics

Question 10

Evaluate animal cloning

Answer 10

For:
- desirable characteristics always passed on
- increasing endangered species= preserves biodiversity
- animals can be cloned at any time
-testing medicinal drugs on animal clones avoids using animals or people for testing

Against:
- success rate is poor. Cloned species tend to live a shorter life
- expensive and time consuming
- no genetic variability = more suspectile to diseases

Question 11

Uses of biotechnology

Answer 11

• food: ethanol in beer and wine + mycoprotein
• drugs: penicillin
• enzymes= lactase to make lactose- free milk

Question 12

Why are microorganisms used in biotechnology

Answer 12

• relatively cheap and easy to grow
• short life cycle so reproduce rapidly
  -ideal geothermal conditions can by easily created

Question 13

brewing

Answer 13

-to make beer yeast is added to a type of grain such as barley. the yeast respires anaerobically using glucose from the grain and produces ethanol and carbon dioxide. (fermentation)= ethanol produces by anaerobic respiration

Question 14

baking

Answer 14

-yeast produces carbon dioxide by fermentation of sugars in the dough which makes the bread rise
-ethanol is evaporated during the cooking process

Question 15

cheese making

Answer 15

-milk is pre-treated with culture of bacteria to produce latic acid which gives the cheese a sour taste. once acidified it is mixed with rennet which contains the enzyme rennin (chymosin) which coagulates the milk.

Question 16

yogurt production

Answer 16

-use of latic acid bacteria to coagulate the milk to thicken it. flavours are added in later

Question 17

penicillin production

Answer 17

-grow during batch fermentation under stressful conditions.
-when stressed fungi from the penicillium genus produces antibiotic penicillin to stop bacteria from growing and competing with resources.

Question 18

insulin production

Answer 18

-made by genetically modified bacteria, which have had the gene for human insulin inserted into their DNA, these bacteria are grown using continuous fermentation. insulin is collected and purified

Question 19

biomediation

Answer 19

• used to clean soil and underground water on polluted sites by removing toxic waste.
  -naturally occurring pollutant-removing bacteria are provided with extra nutrients and enhanced growing conditions to allow them to multiple and thrive. breaks down pollutants into less harmful products. e,g. cleaning up oil spillages at sea

Question 20

evaluation of using microorganisms in food production

Answer 20

• can be grown quickly,easily and cheaply as they have simple growth requirements so can be grown and less land is required
  -can be cultured anywhere. can prevent malnutrition in developing countries
  -single-cell protein is considered a healthier alternative to animal protein

disadvantages
- people may not like the idea of eating food that has been grown using waste products
-if single-cell protein consumed at high quantities can cause health problems due to the uric acid produced when the amino acids are broken down
-protein must be

Question 21

fermentator

Answer 21

-pressure vent at the top to prevent any gas build up
-air inlet=sterile air provides oxygen in aerobic fermenters
-mixing blades which rotate using the motor
-water jacket inlent at the bottom to allow circulation of water to regulate temperature
-outlet tap= bottom for draining product
-inlet for addition of nutrients
-water jacket outlet
-electric probe to measure temperature,PH and oxygen levels
-air outlet

Question 22

batch fermentation

Answer 22

-microorganisms grown in individual batches.when one culture ends it is removed and another is added (closed system)
-makes secondary metabolites in the stationary phase
-no new materials is added

Question 23

continuous fermentation

Answer 23

-microorganisms are continuously grown in fermentation without stopping the vessel, nutrients are put in and waste products taken out at a constant rate. (open system)
-makes primary metabolites in the log phase

Question 24

the standard growth curve of a microorganism in a closed culture

Answer 24

• lag phase= population size increases slowly because the microorganisms are adjusting to their environment.
  -log phase= population size increases quickly because culture conditions are most favourable for reproduction e.g. enzymes need + sufficient nutrients
• number of cells in culture doubles at regular intervals so formula =N=N0 x two n (check CGP)
  -stationary phase= the population stays level because the death rate of microorganisms equals their reproductive rate as organisms use up their waste products
  -death phase= the population size begins to fall because the death rate is greater than the reproductive rate. food is scarce and waste products are at a toxic level

Question 25

aseptic techniques

Answer 25

-prevent the growth of unwanted microorganisms that may affect the growth of the microorganisms being cultured

-sterilisation = medium is steralised by heating
-inoculation= inoculating loop and neck of the bottle is sterallised using bunsen burner
methods: streaking = loop is used to transfer a drop on the agar surfaces which is then spread out by dragging the loop acroos
-seeding= sterile pipette used to transfer a small drop of liquid medium to the surface of the agar
-spreading= a sterile glass spreader is used to spread the inoculating loop drop on the surface of the agar
-incubation = petri dish labelled,taped
-places upside down to prevent drops of condensation falling onto the surface of agar
-left to grow in suitable condition

Question 26

serial dilutions

Answer 26

• used to reduce the population density to obtain visible colonies of the agar plate
  -method described in text book
• once have a visible colonies multiple the number counted by the dilution factor and the volume added

Question 27

immbolised enzymes

Answer 27

methods to immoboilise enzymes
- adsorption: enzyme molecule is bound to supporting surfaces by a combination of hydrophobic interactions and ionic links such as clay. active sites are exposed and so accessible to the substrate.however, may be slightly distorted by the additional interactions affecting the enzyme activity, bonding forces are not as strong so become detached and leak into the reaction mixture

• Covalent bonding; enzymes are bonded to a supporting surface such as clay and bonded to other enzymes using cross-linking agent. covalent bonding is stronger so enzymes are less likely to become detached
• entrapment: enzyme molecules are trapped in a matrix . enzyme molecule unaffected by the substrate molecule must be able to diffuse in and the product molecules able to diffuse out. so only suitable for small molecules. calcium alginate beads are often used to immobilize enzymes or cellulose mesh

Question 28

evaluation of immobilised enzymes

Answer 28

advantages
-enzymes can be reused so it reduces the costs
-no money spent separating the enzymes from the product
- can be used at a high temperatures or extreme PH’s as they denature less easily
disadvantages
-extra equipment needed
-more expensive to buy so not always economical for used in small-scale
-can lead to reduction in enzyme production

Question 29

glucose isomerases

Answer 29

-used to convert glucose into fructose which is sweeter than glucose so can be used in diet foods as less need to be added to obtain the same sweetness

Question 30

penicillin acylase

Answer 30

• used in the formation of semi-synthetic antibiotics which are not resistant

Question 31

lactase

Answer 31

• used in the hydrolyses of lactose to glucose and galacatose to produce lactose-free mik

Question 32

aminoacylase

Answer 32

• used in the production of pure samples of L-amino acids which can be used in the production of human and animal food

Question 33

glucoamylase

Answer 33

-breaks down dextrins (form of starch) into glucose