Q6 - PTEN Knockdown and Neutrophil Differentiation

Theoretical 2 Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license

HL-60 cells differentiate to neutrophils after eight days of incubation in the presence of All Trans retinoic acid (ATRA). siRNAs are synthetic molecules used to suppress expression of genes. In the experiment whose results are presented below, an siRNA against the PTEN gene was used. Annexin V is a marker used to show apoptosis, and CD11b is a neutrophil surface marker. Percentage of apoptotic and differentiated cells as well as combination of both are shown in panels A, B and C. In panels A and B, stars indicate statistical significant. (C) Horizontal line within each box reflects threshold value for apoptosis. Vertical line within each box reflects threshold value for neutrophil differentiation.

Figure 1. Figure 1.

Using the information and data, determine which of the statements are true or which are false.

A. The level of differentiation to neutrophils in the presence of PTEN siRNA is less than in the absence of PTEN siRNA at a statistically significant level.

B. Panels a and b show that reduction of apoptosis causes an increase in the number of live neutrophil cells at all time points.

C. Panel c shows an inverse correlation between apoptosis and the number of differentiated neutrophil cells at at least two time points.

D. PTEN siRNA applications causes larger reduction of apoptosis in differentiated cells as compared to undifferentiated cells after 7 days of incubation with ATRA.

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Question reproduced from IBO 2018, Theoretical Paper 2, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)