Precision will be reduced, but yield will be increased

Optimisation of a PCR reaction is often a compromise between the competing demands for precision, efficiency and yield. Although the specific effects may vary, generally, increasing the annealing temperature will increase non-specific primer binding and reduce precision. Increasing the length of the elongation phase will reduce the proportion of incomplete newly-synthesised strands and therefore increase yield. In this case, the potential effect on efficiency is unclear. Increasing the elongation phase would increase the reaction time, but the time taken to ramp down to a lower annealing temperature would be reduced.

Which of the following will provide least specific amplification in qPCR?

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#Question id: 12483

#Unit 2. Cellular Organization

ATM and ATR are protein kinases that become activated following specific types of DNA damage. 

A. ATM becomes activated in response to double‐strand breaks, which are detected by the MRN protein complex. 

B. ATR becomes activated by protein‐coated ssDNA that forms when replication forks become stalled or the DNA is being repaired after various types of damage.

C. ATR phosphorylates and activates the checkpoint kinase Chk2, which phosphorylates p53. D. ATM phosphorylates and activates the checkpoint kinase Chk1, which phosphorylates and inactivates the phosphatase Cdc25.

Which of the following combination is incorrect?

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#Question id: 12484

#Unit 2. Cellular Organization

Match the following.

Column I	Column II
A. APC/CCdc20	i . responsible for ubiquitinating proteins, such as mitotic cyclins
B. APC/CCdh1	ii. responsible for destroying proteins, such as securin
	iii. promotes the metaphase–anaphase transition
	iv. Promotes exit from mitosis

Which of the following is correct?

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#Question id: 12485

#Unit 2. Cellular Organization

Following statements are regarding to the centrosome cycle of an animal cell.

A. During G1, the daughter procentrioles continue to elongate.

B. During S phase, daughter procentrioles form adjacent to maternal centrioles so that two pairs of centrioles become visible within the centrosome. 

C. During G2 phase, the centrosome contains a single pair of centrioles.

D. At the beginning of mitosis, the centrosome splits, with each pair of centrioles becoming part of its own centrosome. As they separate, the centrosomes organize the microtubule fibres that make up the mitotic spindle.

Which of the following option is correct? 

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#Question id: 12486

#Unit 2. Cellular Organization

Which of the following process occur in prometaphase?

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#Question id: 12487

#Unit 8. Inheritance Biology

Neurofibromatosis type 1 is one of the most common autosomal dominant disorders. A woman with neurofibromatosis type 1 has an unaffected partner. Which of the following is correct regarding their children?

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#Question id: 12488

#Unit 8. Inheritance Biology

Retinoblastoma usually occurs as a sporadic event but in around 10% of cases there is a positive family history due to autosomal dominant inheritance. In these families the penetrance is approximately 80% (= 0.8). A woman with retinoblastoma, whose father and grandfather were also affected, has an unaffected partner with no relevant family history. Which of the following is correct regarding their children?