9 In your study of a new bacterial species you have identified a transducing phage that you call Px. In addition you have worked out methods to make random transposon insertions into the bacterial genome. You have generated two different transposon insertion collections one with 105 random Tn5 (Kanr) insertions and the other with 105 random Tn10 (Tetr) insertions. You grow Px phage on the mixed collection of Tn5 insertions and use the resulting phage lysate to infect the mixed collection of Tn10 insertions. You select 10,000 Kanr  transductants and find that 80 of them are Tets. Use this information to estimate the total size of the bacterial genome assuming that both Tn5 and Tn10 insert randomly and that the average size of a fragment recombined into the recipient genome during Px transduction is 55 kbp. (Tn5 is about 5 kbp and Tn10 is 10 kbp.)

#Question id: 2983

#SCPH06 I Botany

Cell cycle is regulated by master regulators (cyclin and CDKs). In vertebrates, G1 CDK activity rises during G1 and is stimulated by the presence of growth factors. When signaling from growth factors is sustained, the resulting cyclin D–CDK4/6 complexes begin phosphorylating Rb, releasing some E2F, which stimulates transcription of the genes encoding cyclin E, CDK2, and E2F itself. In a particular cell type there is a mutation in Rb such that it cannot be phosphorylated. What will be the correct expression pattern of cyclin E in these cells after mitotic stimulation?

#Question id: 2984

#I Life Science/ Life Sciences Group – I-V

Certain unicellular eukaryotes, including diatoms and some yeasts, have mechanisms of nuclear division that may resemble intermediate steps in the evolution of mitosis. Which of the following is a characteristic feature of nuclear division in these organisms?

#Question id: 2984

#SCPH06 I Botany

Certain unicellular eukaryotes, including diatoms and some yeasts, have mechanisms of nuclear division that may resemble intermediate steps in the evolution of mitosis. Which of the following is a characteristic feature of nuclear division in these organisms?

#Question id: 2985

#I Life Science/ Life Sciences Group – I-V

Use the figure to answer the question below. The unlettered circle at the top of the figure shows a diploid nucleus with four chromosomes that have not yet replicated. There are two pairs of homologous chromosomes, one long and the other short. One haploid set is black, and the other is gray. The circles labeled A to E show various combinations of these chromosomes. What is the correct chromosomal condition for one daughter nucleus at telophase of mitosis? 

#Question id: 2985

#SCPH06 I Botany

Use the figure to answer the question below. The unlettered circle at the top of the figure shows a diploid nucleus with four chromosomes that have not yet replicated. There are two pairs of homologous chromosomes, one long and the other short. One haploid set is black, and the other is gray. The circles labeled A to E show various combinations of these chromosomes. What is the correct chromosomal condition for one daughter nucleus at telophase of mitosis? 

#Question id: 2986

#I Life Science/ Life Sciences Group – I-V

During ubiquitin-mediated protein degradation in various events of cell cycle, ubiquitin-protein ligases ubiquitinylate substrate proteins, marking them for degradation by proteasomes. Cyclins are degraded through the action of two different ubiquitin-protein ligases, SCF and the anaphase-promoting complex or cyclosome. Following statements are regarding to SCF and APC/C.

A. SCF controls the G1–S phase transition by degrading G1/S phase cyclins and, CDK inhibitory proteins.

B. APC/C degrades S phase and mitotic cyclins, thereby promoting the exit from mitosis.

C. SCF and APC/C are multi-subunit ubiquitin-protein ligases that belong to the RING finger family of ubiquitin protein ligases.

D. SCF and APC/C belong to the different ubiquitin-protein ligase family, their regulation is same.

E. SCF recognizes its substrates only when they are phosphorylated.

F. SCF and APC/C both recognizes its substrates only when they are phosphorylated.

Which of the following is incorrect?