In the mating Hfr met- his+ leu+ trp+ × F- met+ his- leu- trp-.  The met marker is known to be transferred very late. After a short time, the mating cells are interrupted and the cell suspensions plated on four different growth media. The amino acids in the growth media and the number of colonies observed on each are as follows:

histidine + tryptophan  250 colonies

histidine + leucine         50 colonies 

leucine + tryptophan    500 colonies

histidine                       10 colonies

What is the order of transfer of the genes

#Question id: 33274

#Unit 2. Cellular Organization

#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: 1928

#Unit 4. Cell Communication and Cell Signaling

Which of the following is a type of tumor that is NOT derived from hematopoietic cells?

#Question id: 876

#Unit 1. Molecules and their Interaction Relevant to Biology

Prion protein is a normal constituent of brain tissue in all mammals which of the following statements are correct regarding prion protein

a) Strains of mice lacking the gene for PrP suffer no obvious ill effect

b) Illness occurs only when the normal cellular PRP or prpc occurs in an altered confirmation called PrPsc

c) The interaction of prpsc with the prpc converts the letter to prpsc initiating a Domino effect in which more and more the brain proteins converted to the disease causing form

d) the structure of prpsc is very different with much of the structure converted to amyloid like Alpha sheet.

#Question id: 33148

#Unit 2. Cellular Organization