Chapter 12 MasteringBiology
What is the difference between a benign tumor and a malignant tumor?
Cells of benign tumors do not metastasize; those of malignant tumors do.
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called __________.
Chromatin
Cytokinesis refers to __________.
Division of the cytoplasm
Chromatids are ___________.
Identical copies of each other if they are a part of the same chromosome.
The spread of cancer cells to other locations in the body is known as __________.
Metastasis
Checkpoints in the cell cycle control system __________.
Regulate the cell through a variety of stop and go signals
What event does not occur during interphase of the cell cycle?
Separation of sister chromatids
What is an example of what doesn't occur in the interphase of a cell cycle?
Separation of the sister chromatids
Which of the following events occurs during anaphase of mitosis?
Sister chromatids are pulled apart toward the opposite sides of the cell
Which of the following phases of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope?
Telophase
A cell biologist examined the DNA content of a cell from a fruit fly larva during the G1 phase and determined that it had 150 units of DNA. After measuring the DNA content of the same type of cell after the G2 phase, it was discovered that the cell had 300 units of DNA. How is this possible?
The DNA was replicated during the S phase of interphase, which occurs between the two G phases.
DNA replication occurs in __________.
The S-phase of interphase in both somatic and reproductive cells
Which of the following structures is/are part of the mitotic spindle?
The aster Nonkinetochore microtubules Kinetochore microtubules Centrosome
Which of the following events occurs during metaphase of mitosis?
The chromosomes align along the metaphase plate of the cell.
Which of the following events does not occur during prophase of mitosis?
The mitotic spindle breaks down.
Which of the following events occurs during prometaphase of mitosis?
The nuclear envelope fragments
How does the process of mitosis differ between most eukaryotes and other eukaryotes such as diatoms and dinoflagellates?
The nuclear envelope fragments in most eukaryotes but remains intact in diatoms and dinoflagellates.
During binary fission in a bacterium ______________.
The origins of replication move apart.
What event occurs during telophase of mitosis?
Two distinct daughter nuclei form in the cell.
The region of a chromosome holding the two double strands of replicated DNA together is called __________.
a centromere
In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?
cytokinesis
During interphase, the genetic material of a typical eukaryotic cell is __________.
dispersed in the nucleus as long strands of chromatin
Observations of cancer cells in culture support the hypothesis that cancer cells __________.
do not exhibit density-dependent inhibition
You would know a dividing cell was a plant cell rather than an animal cell if you saw that __________.
it had formed a cell plate
What event (or events) occur during anaphase?
1) the centromeres divide 2) the centrioles are at opposite poles 3) a spindle made of microtubules is present 4) identical chromatids move to opposite poles
A cell contains 40 chromatids at the beginning of mitosis. How many chromosomes will it contain at the completion of cytokinesis?
20
How many chromatids does a human somatic cell contain after interphase and just prior to mitosis?
92
One event occurring during prophase is __________.
Beginning of the formation of the spindle apparatus
Which of the following statements correctly describes the difference(s) between mitosis and binary fission?
Binary fission involves the replication and division of a single chromosome, whereas mitosis involves the division of multiple, replicated chromosomes.
