The diagram shows the formation of Okazaki fragments in the replication of DNA in prokaryotes.
Why is the formation of Okazaki fragments necessary during replication?
Important Questions on Practice Exam Papers
The diagram shows two stems, one untreated and the other placed in ink for a day.
What causes the difference in these stems?
Scientists investigated the pollination of four species of plants. Each of the species was treated in three ways: some plants had their flowers covered to exclude pollinators, other plants were not manipulated, allowing birds to pollinate them, and a third group was pollinated by hand using a paintbrush. The percentage of the total flowers that developed into fruit was recorded.
Which species of plant is most efficiently pollinated by birds?
Transgenic plants are plants in which one or more genes from another species have been introduced into the genome, using genetic engineering. Some have been modified to resist pests. Bt corn is a variant of maize that expresses cry protein from the bacterium bacillus thuringiensis. This protein is poisonous to certain insects.
Outline how the gene for the cry protein is added to the Bt corn. The levels of uptake by the plant, transcription and translation of the gene for the cry protein were measured. In order to do so, the amounts of DNA, mRNA and protein were detected. The darkness and thickness of the band is an indicator of amounts present. The results for leaves of three different plants (, and ) are shown next to the respective ladders.
