Why do some species employ both mitosis and meiosis, whereas other species use only mitosis?
They need both if they are producing animal gametes.
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?
They have uncoiled to form long, thin strands.
Which of the following is true of kinetochores?
They are sites at which microtubules attach to chromosomes.
Which of the following correctly matches a phase of the cell cycle with its description?
G1: follows cell division
In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this?
large cells containing many nuclei
Which of the following is found in binary fission but not in mitosis?
Duplicated chromosomes attach to the plasma membrane.
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 remain confined to their original site
Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely
a plant cell in the process of cytokinesis.
Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of micro-tubules, its effectiveness must be related to
disruption of mitotic spindle formation.
One difference between cancer cells and normal cells is that cancer cells
continue to divide even when they are tightly packed together.
The decline of MPF activity at the end of mitosis is due to
the degradation of cyclin.
In the cells of some organisms, mitosis occurs without cytoki-nesis. This will result in
cells with more than one nucleus.
Which of the following does not occur during mitosis?
replication of the DNA
What is true of all cancers?
What is true of all cancers?
How do cancer cells differ from normal cells?
Cancer cells may be immortal.
The cell cycle control systems of cancer cells differ from those of normal cells. Select the best explanation for this fact.
Genetic changes alter the function of the cancer cell’s protein products.
If a eukaryotic cell is in the G1 phase of the cell cycle, which statement about the cell’s chromosomes must be correct?
Each chromosome is made of a complex of DNA and associated proteins.
Which statement provides the best description of the interphase portion of the cell cycle?
During interphase, a cell is metabolically active.
A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in
The drug cytochalasin B blocks the function of actin. Which of the following aspects of the animal cell cycle would be most disrupted by cytochalasin B?
cleavage furrow formation and cytokinesis