Among mammals, the reticulocyte cells in the bone marrow lose their nuclei in th

ID: 53887 • Letter: A

Question

Among mammals, the reticulocyte cells in the bone marrow lose their nuclei in the process of differentiation into red blood cells. Yet the reticulocytes and red blood cells continue to synthesize hemoglobin. suggest a mechanism by which hemoglobin synthesis can continue for a long period of time in the absence of the hemoglobin genes. For each E.coli genotype below, indicate whether high levels of beta-galactosidase (LacZ) activity will be produced when grown in lactose or glycerol. crp represents the gene for cyclic AMP receptor protein. Assume all other alleles are wildtype.

Explanation / Answer

Answer for 9.5

Beta-gal activity

Lactose

Glycerol

Genotype

lacl+ O+ Z+

crp- Lacl- O+ Z+

Lacl- O+ Z+

lacls O+ Z+

F' lacl+ O+ Z+/lacl+ O+Z+

F' lacl+ O+ Z-/lacl+ O+Z+

F' lacl+ O+ Z+/lacl+ OcZ+

F' lacl+ O+ Z+/lacl+ OcZ-