6.4: Cloning, biotechnology Flashcards
State one advantage and one disadvantage of using clones to test a treatment for a disease. f215 june 14 q1ci
advantages:
(genetically identical so) all react the same
or genetic variable controlled; [‘no genetic diversity to affect results’]
disadvantages:
expensive (to produce) or don’t see varied response to drug like in real populations (of mice) or idea that
clones (of mice) may have unknown health issue
(which would affect responses); [‘rare allergies / adverse reactions, won’t be seen’]
Adult cell cloning can be used to investigate the development and treatment of disease.
Outline two other potential applications of adult cell cloning.f215 june 14 q1cii
1 idea to produce, elite/ best, animals; [example/ desirable characteristics]
2 idea to save/ preserve, endangered animals; [recreating extinct animals]
3 grow/ produce (spare) , stem cells/ tissues/ organs; [ref to named example of, tissue/ organ;
4 pet cloning/ cloning GM animals/ animals for xenotransplantation
A batch fermenter is used during the production of beer. Fig. 5.1(a) and Fig. 5.1(b) show some changes that take place in the fermenter over the first 6 days.
(a) (i) Describe the pattern of growth of the yeast population in this fermenter. (4mks)
[f215 june 14 q5ai]
1 lag phase / slow increase (in , population / number / percentage) , at start / initially / day 0 - 1 / during day 1 ;
2 log phase / exponential increase / rapid increase , day 1 - 3 ;
3 rate of increase , slows / less steep , days 3 - 4 / during day 3 ;
4 stationary phase / population levels off / population stays at 100% , at end / finally / remaining days / days 4 - 6 ;
5 comparative figures quoted with 2 x-y readings
Fig. 5.1(a) shows that as the sugar concentration decreases the ethanol concentration increases. Explain this relationship. (3mks) [f215 june 2014 q5aii]
1 sugar converted to ethanol ;
2 in anaerobic respiration ;
3 sugar , undergoes glycolysis / converted to pyruvate ;
4 pyruvate , loses carbon dioxide / decarboxylated / forms ethanal ;
5 reduced NAD giving hydrogen to ethanal ;
6 idea of NAD being , regenerated / recycled , (so) glycolysis continues ;
7 correct ref to, pyruvate decarboxylase / ethanol dehydrogenase
Using the information from Fig. 5.1(a), explain why ethanol is considered to be a primary metabolite of yeast. [f215 june 2014 q5aiii]
ethanol is produced in , all yeast growth phases / all of the time [‘produced during normal growth’] or production of ethanol increases as yeast population increases [follows growth curve for yeast] or
idea that ethanol is a normal (metabolic waste) product (of yeast)
Using only the information from Fig. 5.1(a) and Fig. 5.1(b), outline how two factors may limit the maximum size of the yeast population. [f215 june 2014 q5aiv]
1 sugar concentration falls too low ; [very low sugar concentration / sugar concentration decreases as used up]
2 pH falls too low / conditions become too acidic / decrease in pH causes enzymes to denature ; [very low pH / very acidic]
3 high ethanol concentration , damages / poisons / inhibits , yeast; [high ethanol concentration kills yeast]
A mixture of three sugars is added to the batch fermenter at the beginning of the process:
• the monosaccharide glucose, which the yeast uses up first, during days 0 to 2
• the disaccharide maltose, which is used during days 1 to 5
• the trisaccharide maltotriose, which is used during days 4 to 6.
Suggest why the yeast uses the sugars in this order. (3mks) [f215 june 2014 q5b]
1 glucose can , be used / enters glycolysis , directly / without being broken down (first) ;
2 maltose, must , be hydrolysed / have glycosidic bonds broken ;
3 enzyme / maltase , only made when , needed / maltose present / glucose running out ;
4 enzyme induced / gene(s) switched on ;
5 transcription and translation / protein synthesis , takes time ;
6 maltotriose requires, more (2) hydrolysis (reactions) / breaking of more (2) glycosidic bonds or enzyme to break down maltotriose made last;
One large-scale process to produce ethanol uses biotechnology, with yeast acting on sugar in
a fermenter.
Another large-scale process uses a chemical method instead of microorganisms. This method
needs:
• ethene (obtained from oil)
• a high temperature of 300 °C
• high pressure steam.
Discuss the advantages and disadvantages of using yeast to make ethanol rather than using
the chemical method. (6mks) [f215 june 2014 q5c]
advantages of using yeast:
A1 less energy required ;
A2 does not need , high temperature / 300oC / high pressure ; [works well at low , temperatures / pressures]
A3 can use waste material (as a substrate) ; [e.g. sugar cane waste]
A4 substrate is , sustainable / grown each year ;
A5 process does not use up , oil reserves / fossil fuels ;
A6 product is carbon neutral / no carbon footprint ;
A7 [e.g. yeast is readily available / easily accessible / yeast is in plentiful supply / yeast has simple growth requirements / process is less hazardous]
disadvantages of using yeast:
D1 time consuming / takes several days ; [slower rate of reaction]
D2 needs , downstream processing / purification of product ; [need to separate ethanol from yeast]
D3 is, killed/ inhibited, by product ;
D4 can (only) use batch method ; [more likely to become contaminated]
D5 aseptic / sterile , conditions required ;
D6 [e.g. concentration of ethanol produced is limited]
Enzyme immobilisation is an important technique in biotechnology.
Figs 1.1 and 1.2 show two stages in making a bioreactor to remove lactose sugar from milk.
In Fig. 1.1 the enzyme lactase is immobilised in alginate beads.
In Fig. 1.2 milk flows over the beads and the lactose sugar is hydrolysed to two other
sugars.
(a) Suggest and explain how you might use the method shown in Fig. 1.2 to obtain milk that was
lactose-free. (2mks)
[f215 june13 q1]
reduce / slow, flow rate ; [close tap for a time period]
repeat process / run milk through again ;
test for (named) sugars in milk; [glucose, galactose, lactose, Benedict’s test]
(b) (i) Fig. 1.1 and Fig. 1.2 show that alginate beads can be used to immobilise an enzyme.
Outline two other methods of immobilising enzymes.
[IGNORE cross-linking agents]
1 hydrophobic / ionic bond, to (named), solid / support ; [‘insoluble material for solid. Suitable solids = clay, carbon, resin, glass, gold, ceramic beads; adsorption (but not absorption) carrier bound]
2 covalent bond / cross-link to, (named) substance; [cross-link them together. Suitable substances = other enzymes, collagen, cellulose]
3 membrane separation ; [microcapsules]
4 (en)trap / encapsulate / suspend, in (named), matrix ; [Suitable matrix materials = collagen, cellulose, silica gel, hydrogel, but DO NOT CREDIT entangled / alginate]
Enzyme immobilisation is used in the biotechnology industry for the large-scale production of materials.
Discuss the benefits of using immobilised enzymes for large-scale production. (4mks)
1 (enzyme) can be re-used so reduces cost ;
2 product, pure(r) / uncontaminated ; [product not mixed with enzyme]
3 reduced downstream processing costs ; [save money on purifying product]
4 (immobilised enzyme) works at high(er) temperature ; [enzymes not denaturing at increased temperature/ immobilised enzymes thermostable]
5 (immobilised enzyme) works in changed pH ; [enzymes not denaturing in changed pHs]
6 reaction, can be faster / have higher yield, because can be done at higher temperature ; [mp 4 and mp 6 (unless mp 4 already awarded).]
