Identify the stage of mitosis labelled X in the image, giving a reason.
Outline what is indicated by the mitotic index of tissue taken from a tumour. [20 marks]
Explain how mitochondria could have been formed from free-living prokaryotes.
Explain how mitochondria could have been formed from free-living prokaryotes. [20 marks]
The electron micrographs show a typical prokaryote and a mitochondrion.
Compare and contrast the structure of a typical prokaryotic cell with that of a mitochondrion. [40 marks]
The chi-squared value was calculated as shown. Deduce, with reasons, whether the observed
ratio differed significantly from the expected Mendelian ratio.
The chi-squared value was calculated as shown. Deduce, with reasons, whether the observed ratio differed significantly from the expected Mendelian ratio.
The diagram shows one of Thomas Hunt Morgan’s crosses of Drosophila in the early 20th century.
State the type of inheritance shown.
Using the food web, identify a detritivore.
3b. Using the food web, identify a saprotroph.
To account for the observed phenotypic and metabolic differences, researchers analysed mRNA transcript data.
They found certain transcripts over-represented in Arabidopsis plants grown inlong days (dark grey) compared with the amount expected due to chance.Other types of transcripts were over-represented in Arabidopsis plants grown in short days (light grey).
Leaves were removed from Arabidopsis plants that had been grown in long day and short day conditions and the concentration of starch within them was measured.
This was done both at the end of the day (D) and at the end of the night (N) in each of the four stages of development (S1, S2, S3, S4).