Option B - Biotechnology and bioinformatics
Question 1
SLPaper 3A study was carried out in Brazil on the transfer of pollen (cross-pollination) from transgenic strains to non-transgenic strains of soybean (Glycine max). The transgenic crop was resistant to the herbicide glyphosate. The graph below shows the percentage of cross-pollination between transgenic and non-transgenic crops in fields separated by different distances.
Suggest one undesirable consequence of cross-pollination involving glyphosate resistant crop plants with other plants.
Using the data, suggest one recommendation to farmers who plant transgenic soybeans.
Agrobacterium tumefaciens stains pink or red with the Gram stain. Deduce from this result what type of bacterium _
Outline how _
Question 2
SLPaper 3Starch from different sources contains differing proportions of amylose and amylopectin. Potatoes (Solanum tuberosum) have been genetically modified to produce high-amylopectin starch (Amflora potatoes). Heat induces starch to form a gel in excess water. The graph shows gel formation temperature at different amylose concentrations.
Discuss the hypothesis that the temperature at which starches form a gel depends on the degree of cross-linking of amylopectin.
State one advantage of potatoes with a high amylopectin content.
The Amflora potato was approved for industrial applications in the European Union (EU) in 2010 and was withdrawn in January 2012 due to opposition. Discuss reasons for people supporting or opposing the introduction of the Amflora potato in the EU.
Question 3
SLPaper 3Explain the use of two named bacteria in response to pollution incidents.
Question 4
HLPaper 3Corn (Zea mays) is by far the most widely used biopharming plant, followed by soybeans, tobacco and rice. Around the world approximately 400 biopharming products are in open-air field trials.
State one possible application of biopharming.
Explain the use of a viral vector in gene therapy.
Outline the main principles of the Enzyme-Linked Immunosorbent Assays (ELISA) test.
Question 5
SLPaper 3Rice straw waste can be used to produce biogas, but it contains cellulose that is difficult to digest. Bacteria capable of digesting cellulose are found in the cow’s digestive system. Rice straw waste was pre-treated in a batch fermenter with liquid cow manure. A control was kept under the same conditions without the liquid cow manure.
The resultant products of each culture were placed in two separate continuous biogas fermentation tanks with anaerobic bacteria for 30 days under the same conditions. The graph shows the differences in biogas production and amount of methane produced.
Suggest reasons for the use of a batch culture for the first fermentation and a continuous fermenter for the second fermentation.
Using the graph, explain the trend in biogas production over time in the fermenter without pre-treatment.
Suggest one reason for the higher methane content in biogas in pre-treated rice straw waste.
Question 6
HLPaper 3Caenorhabditis elegans, a nematode, was the first multicellular organism whose genome was completely sequenced.
Outline the benefits of using model organisms for studying gene function.
Describe how BLAST can be used to establish phylogenetic relationships between several organisms.
Question 7
HLPaper 3Golden rice (Oryza sativa, GR) is the generic name given to genetically modified rice that produces beta-carotene (provitamin A). Golden rice was created by transforming rice with the gene coding for the PSY protein (phytoene synthase) from daffodil (Narcissus pseudonarcissus) or from corn (Zea mays).
The picture shows variations of rice.
A White wild-type rice
B Yellow Golden rice expressing the gene coding for PSY from daffodil
C Orange Golden rice expressing the gene coding for PSY from corn
[Reprinted from TRENDS in Plant Science, 10(12), S. Al-Babili and P. Beyer, 'Golden Rice – five years on the road – five years to go?',
pp. 565--573, Copyright (2005), with permission from Elsevier.https://www.sciencedirect.com/journal/trends-in-plant-science\]
Outline how scientists would determine whether the gene coding for PSY from daffodils has been taken up successfully by rice DN
Discuss whether production of Golden rice is an example of biopharming.
Agrobacterium tumefaciens was used in the production of Golden rice varieties. Explain how this bacterium is used to produce genetically modified crop plants.
A bioinformatics analysis was performed on the protein PSY transcribed from the gene from corn and from daffodil to obtain the sequence alignment.
On the alignment, identify the longest part of the sequence where the consecutive amino acids are the same.
BLASTp was used to obtain the alignment of the genes coding for PSY. Outline reasons for BLASTn not being suitable for obtaining this alignment.
In the alignment there are dashes (–) in some positions. Deduce what is indicated by these dashes.
Question 8
HLPaper 3Citric acid is produced on an industrial scale and global production is over 1.4 million tons
per year with a rising trend in demand.
State one industrial use of citric acid.
State the scientific name (binomial) of the microorganism usually used in this process.
Question 9
SLPaper 3A sequence of DNA is translated in a continuous reading frame without spaces. Each triplet of nucleotides corresponds to successive amino acids in a polypeptide. The sequence given shows part of one strand of a DNA molecule.
Identify the first triplets of each possible reading frame for this piece of DN
Define what is meant by an open reading frame.
Question 10
SLPaper 3The diagram shows an aerated fermenter commonly used in biotechnology.
Outline a reason for inserting steam into the fermenter before fermentation.
Describe how optimal temperature is maintained inside the fermenter.
Explain how penicillin can be produced in a fermenter.
