Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

The image shows the results of Griffith’s experiment with S and R strains of Streptococcus pneumoniae in mice (Mus musculus).

What is an explanation for the results?

A.  Mice vary in their resistance to bacteria.

B.  The R strain and S strain mated.

C.  R strain bacteria are more heat-stable than S strain.

D.  DNA was transferred from heat-killed S cells to R cells.

A nucleus was removed from a cell of sheep P and fused with a denucleated egg cell of sheep Q. This was transplanted into the uterus of sheep R, which gave birth to Dolly.

[Source: Photo courtesy of The Roslin Institute, The University of Edinburgh, Roslin, Scotland, UK, n.d. Dolly the Sheep
in a field at The Roslin Institute. [image online] Available at: https://www.livescience.com/57961-dolly-the-sheepannouncement-
20-year-anniversary.html [Accessed 23 March 2020].]

Which describes Dolly?

A. A clone of sheep P, because Dolly was formed from the nucleus of its udder cell

B. A clone of sheep Q, because Dolly was formed from one of its egg cells

C. A clone of sheep R, because Dolly developed in its uterus

D. Not a proper clone, as more than one sheep was involved in the development

Ampicillin (Amp) is an antibiotic. A plasmid carrying a gene for Amp resistance was used to transform bacteria in a tube of broth. A control tube without plasmid was also produced. The results were plated as shown. Which plate has only colonies of transformed bacteria?

Two restriction endonucleases (EcoRI and BamHI) were used to cut a DNA sample into smaller fragments. These were then subjected to gel electrophoresis and the results are shown. The lengths of the DNA fragments are measured in kilobases (kb). One kilobase is 1000 DNA bases.

[Source: © International Baccalaureate Organization 2019]

Which statement is supported by the data?

A. The DNA sample is approximately 16 kb in size.

B. Each endonuclease produces a 2 kb fragment.

C. Both endonucleases produce the same number of fragments.

D. The fragments produced using both endonucleases are all different from those produced by the individual endonucleases.

Describe how DNA profiling can be used to establish paternity.

Suggest possible benefits and risks of using genetic modification to develop varieties of crop plant with traits such as drought resistance.

In DNA profiling, short tandem repeats (STRs) of DNA are used, as these vary a great deal between individuals. Some skin cells were retrieved from a crime scene. Three STR sections of the DNA from these cells, from the victim and from a suspect, were analysed and the results are shown in the table.

What can be concluded from the gel electrophoresis data?

A. The suspect was at the crime scene.

B. The victim has the band moving the least distance.

C. The suspect and the victim have bands moving the same distance.

D. The skin cells have the band moving the greatest distance.

Explain the process of genetically modifying bacteria.

A cloning method used for livestock involves in vitro fertilization (IVF) with selected male and female gametes. The diagram shows the steps followed after in vitro fertilization.

[Source: Aldona Griskeviciene / Shutterstock.com.]

What does X represent?

A. A group of eggs

B. An embryo

C. A follicle

D. A group of zygotes

Explain benefits and risks of using genetically modified crops for the environment and also for human health.

Discuss the process, including potential risks and benefits, of using bacteria to genetically modify plant crop species.

Genetically modified maize, called Bt maize, is thought to be affecting the monarch butterfly (Danaus plexippus) in the USA. What is the reason for this?

A. The monarch butterfly feeds on maize nectar, which contains Bt toxin.

B. The monarch caterpillar feeds on maize leaves, which contain Bt toxin.

C. Bt toxin kills the plants that the monarch caterpillar usually eats.

D. Bt toxin is in maize pollen, which blows on to plants that the monarch caterpillar eats.

Each gene is activated by one or more of the treatments. From the gel electrophoresis data, discuss the impact of the herbivorous mite infestation on gene activation compared to treatment with C1 and C2.

Outline the process of DNA profiling.