Given are certain facts which define ‘specification’ of a developing embryo.

 A. At the specification stage, commitment to cell identity is labile.

 B. At the specification stage, cell is capable of differentiating autonomously.

 C. The cell “knows” very early what it is to become without interacting with other cells.

 D. A phase where inductive signals trigger cell to determines their fate.

 Which of the above statements best define specification?

#Question id: 3839

#Unit 3. Fundamental Processes

Use the figure to answer the following question. In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" (radioactive) nitrogen (15N) and then transferred them to a medium containing 14N (nonradioactive). Which of the results in the figure would be expected after one round of DNA replication in the presence of 14N?

#Question id: 3840

#Unit 3. Fundamental Processes

The mechanism of DNA replication is studied in an E. coli replication fork. When will this fork stop replicating DNA?

#Question id: 3841

#Unit 3. Fundamental Processes

The DNA replication occurs in a semi-conservative manner which means

#Question id: 3842

#Unit 3. Fundamental Processes

Which of the following statements correctly describes the difference between the leading strand and the lagging strand in DNA replication?

#Question id: 3843

#Unit 3. Fundamental Processes

In DNA replication in E. coli, the enzyme primase is used to attach a 5 to 10 base ribonucleotide strand complementary to the parental DNA strand. The RNA strand serves as a starting point for the DNA polymerase that replicates the DNA. If a mutation occurred in the primase gene, which of the following results would you expect?

#Question id: 3844

#Unit 3. Fundamental Processes

The lagging strand is characterized by a series of short segments of DNA (Okazaki fragments) that will be joined together to form a finished lagging strand. The experiments that led to the discovery of Okazaki fragments gave evidence for which of the following ideas?