Biotest 11-13

A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain?

Why is it difficult to observe individual chromosomes with a light microscope during interphase?

Which of the following is true of kinetochores? They interdigitate at the cell's equator and then move apart, causing the cell to elongate. They attach to the ring of actin along the cytoplasmic surface of the plasma membrane, causing the actin to contract to form the cleavage furrow. They are located at the center of the centrosome; their function is to organize tubulin into elongated bundles called spindle fibers. They are the primary centromere structures that maintain the attachment of the sister chromatids prior to mitosis. They are sites at which microtubules attach to chromosomes.

Which of the following correctly matches a phase of the cell cycle with its description? M: duplication of DNA G2: cell division G1: follows cell division S: immediately precedes cell division All of the above are correctly matched

In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this?

Which of the following is found in binary fission but not in mitosis? Replicated strands of DNA separate. Following the process, a membrane separates the 2 copies. Replication of DNA begins at an origin. Duplicated chromosomes attach to the plasma membrane. The result produces 2 nuclei.

Cytochalasin B is a chemical that disrupts microfilament formation. How would this interfere with cell division?

Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle?

Which of the following is true of benign tumors, but not malignant tumors? They migrate from the initial site of transformation to other organs or tissues. They can divide indefinitely if an adequate supply of nutrients is available. They are the result of the transformation of normal cells. They remain confined to their original site They have an unusual number of chromosomes.